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ARP Axxe Repair Thread (was Cleaning Vintage (Arp) Sliders)
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Author ARP Axxe Repair Thread (was Cleaning Vintage (Arp) Sliders)
valis
Greetings, I'm sorry if this subject has been talked about to death on various sites. I've been doing some research into how to best clean some sliders on an Arp Axxe and there's a million different methods so I'd love some advice, preferably from people who have experience with this sort of thing thumbs up

Anyway, like I said, I have an old Arp Axxe that is in need of a cleaning. At the moment I'm going for improvement, not necessarily a new feeling synth.

It seems like the best method, and the one endorsed by the legendary Kevin Lightner is to use pressurized soft water and then air dry the board. This is not really an option for me. I don't have the resources to do this so I'd prefer not to try. I know I could unsolder the sliders and wash them by hand but again, I'd like to try to avoid this..

I suppose I could get some bottled water and wash the entire board in a big pan and dry it with either compressed air or gently with a blow dryer. Thoughts on that? I do have some concern about not completely drying the board and something rusting (or worse)..

Buying replacement sliders is out of the question right now as I'd like to try to DIY it. And Yes, I've worked on synths before..

Anyway, moving on..

There's the Isopropyl Alcohol method. I have 91% Isoprophyl Alcohol and could clean the sliders with a q-tip or even a syringe. I am concerned with residue not evaporating and being left in the slider shaft though. Still, people seemed to of successfully used this method to clean there Oddys (see AH).

I don't want to do the Deoxit thing after reading some horror stories (and since it really won't clean out the sliders very well but just moved the gunk around).

Also..

After I'm done I assume that I'll need some fader lube. What are peoples' opinions of GC Luberex, Caig Fader Grease, or Caig Fader Lube?

Thanks for Reading!
dude
i am in the exact same boat and would love input as well. my axxe and little brother need a good slider cleaning/lube. anybody?
valis
Damn, two Oregonians with some dirty Axxes..
Luka
i heard the only way to really refurb them is to desolder, dissasemble, clean (scrub), relube, reassemble, re-solder

and it sounds like a PITA


im not sure if squirting any kind of liquid into them is going to help
dude
Luka wrote:
i heard the only way to really refurb them is to desolder, dissasemble, clean (scrub), relube, reassemble, re-solder

and it sounds like a PITA


im not sure if squirting any kind of liquid into them is going to help


i SO don't want that to be true, but i have heard the same. very frustrating
Luka
i was going to do this for a friend until i learnt the process :(
(which i heard from our local synth tech guru)
valis
Here's KL cleaning an Odyssey with water. It looks like a great method but I'm not sure how I'd get the water pressure (or if there's anywhere in town that has softened pressurized water)..



I really don't want to take those sliders apart, or at least not without some practice..
valis
Are the faders on an Axxe "carbon compound faders?"
dude
hmmm. that looks scary.
JohnLRice
FWIW . . .

You could try Caig FaderLube:
http://store.caig.com/s.nl/sc.2/category.293/.f

This page has a link to a PDF that gives some usage instructions:
http://store.caig.com/s.nl/it.I/id.52/.f?sc=17&category=-117
dude
oh john thanks for that. i hope that it will do the trick. i am talking to my local techs about their thoughts.
valis
Let me know what your tech say. I'm going with some fader lube and some Isoprophyl Alcohol, as recommended by Tim Servo..

http://old.nabble.com/Anyone-find-a-good-lube-for-arp-odyssey-style-sl iders--td8878179.html#a8895795

I'd be all about the water method if I had pressurized soft water and a thorough way of quickly drying the board (Oregon in November isn't really a good place for anything to dry)..

JohnLRice wrote:
FWIW . . .

You could try Caig FaderLube:
http://store.caig.com/s.nl/sc.2/category.293/.f

This page has a link to a PDF that gives some usage instructions:
http://store.caig.com/s.nl/it.I/id.52/.f?sc=17&category=-117


Anybody have any experience with Caig FaderLube? There seems to of be some horror stories over at AH regarding using Deoxit..
Reptil
when the fader is clean the lub e is excellent.
I got some spare faders this weekend, but I'm interested in cleaning
+1 that Odyssee in the shower looks scary eek! help
emdot_ambient
valis wrote:
Damn, two Oregonians with some dirty Axxes..

I've got 'em beat...I'm one Marylander with two dirty Axxes..

If anyone gives this a go, let me know how it works out. I'm going to spring for new keyboard bushings soon for both of them and my (broken) Minimoog. I was thinking of just going ahead at some point and getting new sliders altogether...but that would be about $229 + shipping from the UK, or $319 + shipping if I got enough to do my ARP Sequencer, too. Still, that's not a bad price considering it's only about $4.90 per slider for the AXXE with 23 sliders total (this is based on the kits from http://www.synthrestore.co.uk/products.htm which are out of stock until Dec '09).

Add about $46 for keyboard bushings per AXXE and $50 for the Minimoog...about $500 total to refurbish 2 AXXE, 1 Minimoog (not including its malfunctioning PSU or any other needed replacement parts) and 1 Sequencer.
valis
I just gave the Axxe a shower yesterday and *knock on wood* everything appears to be good. The sliders feel a lot better but I'm waiting for some Fader Lube to come in the mail before I reassemble to unit and give it a full test..
dude
valis wrote:
I just gave the Axxe a shower yesterday and *knock on wood* everything appears to be good. The sliders feel a lot better but I'm waiting for some Fader Lube to come in the mail before I reassemble to unit and give it a full test..


cheers,

uz gotz ballz.

respek!
valis
dude wrote:


uz gotz ballz.




Lol, that much is true!



I've been detailing my adventures with the Axxe and some of my other synths on my pretty lame blog:

http://obsolete-synthesis.blogspot.com/

I haven't updated it to reflect the bath since I'm waiting for the FaderLube to come in the mail. Still, There's some info on disassembling the case and cleaning the keys, case, etc. I'm certainly no great expert so take everything with a grain of salt if, you're interested enough to look..
scozbor
yes I have a roland sh3a. the filter does not work any more.

more precisely, the resonance does not seem to work. the cutoff acts like a volume knob. The filter still passes audio though.

i'm wondering if it's just the fader....
emdot_ambient
valis wrote:
...http://obsolete-synthesis.blogspot.com/

That email from KL is most reassuring. I'm pretty sure I'll do the same thing...let us know how it goes, though; I"ll still let you be the guinea pig

lol
emdot_ambient
valis wrote:
...http://obsolete-synthesis.blogspot.com/

Oh...As you mention, the AXXE's circutry is very simple. Ever considered modding it? Seems to me it would be fairly easy to make the thing semi-modular. I've seen one online that had that done, have always thought about doing some of that.
valis
emdot_ambient wrote:
valis wrote:
...http://obsolete-synthesis.blogspot.com/

That email from KL is most reassuring. I'm pretty sure I'll do the same thing...let us know how it goes, though; I"ll still let you be the guinea pig

lol



Lol you may as well let me be the guinea pig. I didn't really want to do it but the sliders were and absolute mess. All things considered, I think this method is safer than me unsoldering all the sliders, taking them apart, cleaning the insides, reassembling them, and resoldering them back on the board. There's a lot that can go wrong there. Plus washing the board addresses some other issues.

Truth be told, I didn't fully submerge the circuit board. I filled up a water sprayer with very warm distilled water and blasted the sliders, back of the board, and other components. It was much more of a controlled washing. Then I took some Q-tips and 99% Isoprophyl Alchohol and cleaned out in the sliders. I'll go more into detail later.

Yeah, that email from KL was most encouraging. I thought it was pretty awesome he sent it.

Anyway, I'll post details and pics after my package comes and I put the thing back together. Everybody keep there fingers crossed for me..
valis
emdot_ambient wrote:

Oh...As you mention, the AXXE's circutry is very simple. Ever considered modding it? Seems to me it would be fairly easy to make the thing semi-modular. I've seen one online that had that done, have always thought about doing some of that.


You may be referencing this website that has some very interesting Axxe mods:


http://www.cykong.com/Synths/ARP%20Axxe%20AS%20Modular/ArpAxxeModular( AS).htm
(I cannot get that URL to properly format. If you're interested in seeing it, just copy the whole thing into your browser without any spaces..)


I've considered doing some mods but truthfully it's pretty far down my to-do list. I'm sure they'd be real simple but I already have some old monos I've modded to be semi-modular so this isn't a huge priority. As the machine stands, with it's gate in/out, trigger in/out, CV in/out, and audio to the VCF, it'll adapt really nicely in a modular studio.

I have a buddy who bought an Axxe circuit board on Ebay some time ago. He plans to make his Axxe into a modular machine. I'll let you know how that goes if it ever happens..
emdot_ambient
That's the site. I'd rather run all the jacks out the back...and maybe just do them as 1/4"...I HATE 3.5mm jacks and plugs! Cheap ass things.

Before I go modding mine (assuming they're working), I'll probably do something about the wiring of the Gate/Trigger/CV.

The way they've done, if you run a Gate/Trigger/CV into an AXXE, it disconnects the keyboard, making that AXXE a slave to the input signal.

The keyboard of the slaved unit becomes a big waste of space. What I'd like is to have a Keyboard Gate/Trigger/CV output that's independent. It would be disconnected from the PCB's inputs, but shunted to 3 separate jacks so that it could still be used to control other modules, like transposing a sequencer.
valis
Hey All,

With the acquisition of another 1970s monosynth this week, I'm moving right along with my Axxe project. I thought some of you might be interested in how things are going/went. If anybody is interested in fuller details they can go here:

http://obsolete-synthesis.blogspot.com/2009/11/arp-axxe-restoration-po stings.html

.. But here is the rundown:


Overall Impressions:

Success! After doing this wash, the synth feels, plays, and, sounds worlds better. I'm quite happy that I went through all of the trouble because it really is a fabulous sounding synthesizer. Excellent tone, great filter, an absolute gem. All and all, this method was definitely a success and worth the trouble. It's definitely not factory new but it is much better now.

Original Problems:
Extremely stiff and dirty sliders, sine LFO not working, S&H not working , White Noise not working, Saw Wave oscillator not working, Saw Wave oscillator slider not working, something weird going on with ADSR and oscillator, strange persistent tone that played after every note you played.

Remaining Problems:
I still can't get any White Noise out of the machine and the Sample and Hold still is not working. I'm sure that the two issues are related since the Sample and Hold triggers from the White Noise source. I suppose that I'll have to look at the schematic and see if I can figure out what is going on..

Things left to do:
Fix the White Noise and the Sample & Hold problem, fix bushings, I should probably go through the calibration procedures, replace power cord (slight fraying near chassis).

Method Used for Cleaning:
Heated purified water and a spray bottle for the circuit board and sliders, 99% Isopropyl Alcohol and some Q-tips for the sliders, water and a little dish soap for slider caps and case, a bit of Caig Fader Lube for the sliders, Mr. Clean Magic Eraser for the keys.

Pictures:

ARP Axxe before restoration




A clean Axxe



Note: Both of these previous two "before and after" pictures have been brightened in Photoshop. I've been having problems getting good lighting with the camera that I have. The keys are definitely not that glowing white!



Here's a picture of the Axxe that hasn't been brightened at all. You can see that there's still some yellowing to the keys and some of the bushings are off a little. The slider caps, of course, also haven't been put back on. Still, it looks much better..



Keyboard Before:


Keyboard After:



Sliders Before:


Sliders After:



Caps and Knobs Before:



Caps and Knobs After:


(See previous picture in this forum of the ARP circuit board in the shower)
emdot_ambient
valis wrote:
Method Used for Cleaning:
Heated purified water and a spray bottle for the circuit board and sliders, 99% Isopropyl Alcohol and some Q-tips for the sliders, water and a little dish soap for slider caps and case, a bit of Caig Fader Lube for the sliders...

Sweet! OK, so did you use the spray Faderlube or squeeze bottle or what?

...and how did you dry it?

Also, are you considering replacing the keyboard bushings? If the keys are stiff or clack when you play them, it's 'cause the bushings have dried out and become hard. Replacing them pretty much restores its Pratt-Read keyboard to how it originally felt.

I'm going to give both of my AXXE's a bath and then replace their bushings. See how that goes before I do drastic things like replacing sliders or shelling out for a real tech to look at them.

thumbs up Thanks for the update!
Luka
good job
perhaps i will try on my friend's od.
valis
Luka wrote:
good job


... Thanks Luka!

emdot_ambient wrote:

Sweet! OK, so did you use the spray Faderlube or squeeze bottle or what?


I used the little bottle with the small pin nozzle that you can put a few drops into the slider. It's the Caig F100L I think. I want to be able to control the exact amount of liquid going into my faders so this is the best option for me.

emdot_ambient wrote:

...and how did you dry it?


This is taken from my blog:

The first thing I did was heat up some purified water. I put it in a water sprayer and sprayed the sliders, trimmers, components, and board. I did this for a few minutes and then dried the board with some fans, a hair dryer (which I always kept at least a foot away from the board), and some compressed air (which I also kept a safe distance from the board). I was concerned when I was using compressed air that it might actually freeze the water on the board thus causing it to expand and cause cracks in the board or a component. A blow dryer could also cause problems if it were too close to the board. Therefore, I was very careful.

I dried the board as quick as possible and made sure that there was no remaining water. After this process I could tell the sliders felt a lot better. During the wash I could see pools of dirt flooding out of the sliders.


[I live in Oregon, USA so getting anything dry during this time of year can be difficult. I had numerous fans going prior to me washing the board and during the wash as well. I worked quickly and meticulously. Both the compressed air and blow dryer were very helpful, although like I noted above, needed special care. I was very sure to spray air inside the pots and under all the components that are a little elevated from the board so as to be sure all the water was gone. When I was done with the board, I was 100% sure that it was dry.]


emdot_ambient wrote:

Also, are you considering replacing the keyboard bushings? If the keys are stiff or clack when you play them, it's 'cause the bushings have dried out and become hard. Replacing them pretty much restores its Pratt-Read keyboard to how it originally felt.


That's good info. I actually know very little about keyboard bushings as I've focused most of my energy on synth electronics and not mechanics. At some point I'd definitely like to replace the bushings, but it's not a super huge deal to me right now. Especially if it's going to be a time consuming project. All of the keys trigger well and predictably, although it would be nice to have that better keyboard feel. Right now I'm a lot more interested in getting that S&H working (which wasn't working before the cleaning either)..


emdot_ambient wrote:


I'm going to give both of my AXXE's a bath and then replace their bushings. See how that goes before I do drastic things like replacing sliders or shelling out for a real tech to look at them.

thumbs up Thanks for the update!


I honestly think you can solve most of your problems by blasting the sliders with some water. Kevin Lightner seems to think the same thing (see my previous post with the link to Kevin's how-to posting). I would doubt your Axxes are dirtier than my Axxe was.

Definitely keep me/us updated as to your Axxe project. I'm very interested to see how your bushing replacement goes..

Let me know if you need any help with anything (service manual, pics, etc.)

My three part posting regarding taking apart the Axxe, washing the case, board, components, and sliders is here:

http://obsolete-synthesis.blogspot.com/2009/11/arp-axxe-restoration-po stings.html
emdot_ambient
The bushings don't look very hard to replace. The process is basic enough; pull off the old ones making sure not to leave any old bushing remnants, and then pop on the new ones.

I've seen pics of people doing it without taking off the key caps, but it's probably easier to take them off...the harder way is to take off the key caps AND the springs, AND the metal key carrier. This is harder and you have to make sure you keep the springs segregated as the white and black keys have different springs...but once you do this all the bushings are exposed and easy to remove.

A pretty clear picture of the bushings are here: http://www.flickr.com/photos/hobby_synth/888549570/

Those are from a Minimoog actually, but they use the same Pratt-Read keyboard, only the mini has more keys. The bushings are the white things with the funny looking "ear" protrusions. They can be different colors, usually black or white. New ones are soft and pliable with a lubricant on them. Old ones are dry and somewhat crumbly, no give and may break apart.
valis
That's interesting info. Thanks. I'd still need to do a little more research before replacing the bushings for my own sake but you've sold me on the relative ease of replacement.

If you end up replacing your bushings please take some pics and share!


(edited due to horrible spelling)
emdot_ambient
Will do, but it'll be a little while. No need for me to go through that trouble until I have enough cash for a power supply for my first modular gear.

At that point I'll need a CV/Trigger/Gate source and I plan on using my 2 Axxe as controllers...then I'll need to do the cleaning/bushing thing.
mono-poly
Giving a bath with wather is a perfect solution.

http://www.synthfool.com/arp2500takingbath.jpg

http://www.synthfool.com/fleabath.jpg
Babaluma
that's one of the best before and after synth shots i have ever seen. congratulations on your hard work!
valis
emdot_ambient wrote:


At that point I'll need a CV/Trigger/Gate source and I plan on using my 2 Axxe as controllers...then I'll need to do the cleaning/bushing thing.


Yeah, that was one of my motivations for pushing this project forward so quickly. The ARP seems like it'll make a great controller and companion for a modular. It's cool those real early ARP and Moog systems were, in some ways, designed to interact with their other modular stuff. It seems like Moog and ARP still weren't 100% sure what people would need on a normalized synth in the early 1970s so they kept their systems very open. Very cool era for synths..

mono-poly wrote:
Giving a bath with wather is a perfect solution.

http://www.synthfool.com/arp2500takingbath.jpg

http://www.synthfool.com/fleabath.jpg


Yeah, Kevin Lightner was the inspiration to use this method. I asked some questions and debated some reasoning over at AH and he dropped me (and a few others) a long msg (and a follow up) regarding how he cleans synths. Here's the main msg if you're interested:

http://old.nabble.com/MSG-From-Kevin-Lightner----Fwd%3A-ody-cleaning.. -2-cents-more.-%3A)----ts26453301.html#a26453301
(copy the whole URL. When I tried to embed it as a URL my post went all wonky)

Again, I didn't use the full submersion method. This method is, I'm sure, the most thorough but I still didn't feel comfortable with my ability to get it thoroughly dry so I just blasted the board and components with a spray bottle of water..

Babaluma wrote:
that's one of the best before and after synth shots i have ever seen. congratulations on your hard work!


Thanks for the very kind words. It was by far the dirtiest synth I've ever worked on and it turned out pretty well, especially considering I'm still in my intermediary stages of DIY techdom. This was a really fun project though. Now I really want to get the S&H working on it. Seems like a project for my days off..

Anyway, I'm glad that people got a little benefit out of this posting...

All the best and many thanks,
David
emdot_ambient
FYI, I've ordered the keyboard bushings for one of my AXXEs and have already received the faderlube. I've also purchased a plastic pump up bottle to use as my sprayer, rather than risking using tap water and a shower head. I wasn't convinced the spray bottle like valis used would give me enough pressure or control. I'm going to use distilled water to be on the safe side. I don't know if my tap water is hard or soft.

So probably in a week or so I'll be venturing into this...I'll probably do it on my 2nd hand AXXE first. Clean its sliders, and see how that works. Then if I'm satisfied, clean the AXXE I bought new (it's in a bit better shape than the other one) and replace the bushings on that one.

Theoretically I'll end up with 2 useable synths with one of them feeling more like new as far as its keyboard action goes. I'll get the bushings for the other one some time later.
valis
Awesome. I'm pretty confident that you'll have a pretty high success rate. That's a good call on the plastic pump, the spray bottle is not ideal. Where did you find such a contraption?

Good luck replacing the bushings, you'll have to tell us how that goes. Ever since your posts about bushings, every time I play with the synth I think that I should replace them.

On another note, I'm pretty sure I've found my Sample & Hold/White Noise problem (*knock on wood*). It appears that I have a bad LM301AN (Z2), which fortunately is still available at Mouser.

Good luck on your restoration and don't forget to make sure it's dry under all those components Mr. Green

-David
emdot_ambient
valis wrote:
...That's a good call on the plastic pump, the spray bottle is not ideal. Where did you find such a contraption?...

Actually found it at Home Despot, uh, Depot. I already had one, but I had used it for bug spray and didn't think that would be too good to use.
emdot_ambient
Just got the bushings in the mail. Wow, they're much smaller than I thought they'd be. Quick mailing, though, only took a few days between order and receipt of goods.

I'll do pics when I get around to acutally cleaning and changing the bushings.
valis
Awesome. Good luck on your project..
valis
I replaced Z2 with another LM301AN and I have pink noise now (hooray!) but I don't think the S&H is functioning properly. I assume that it works like any other S&H with a white noise control source (i.e. random triggered notes for infinity). Mine's acting more like a portamento or weird LFO. I'll examine the schematic closer later..

NV
Very nicely done. That Mr. Clean Magic Eraser cleaned up those keys nicely. Strange that they are yellowing in such an ordered fashion - all the A, B, D, and F keys and none of the others save for the high C. Different manufacturers for the specific keys I guess.
valis
NV wrote:
Strange that they are yellowing in such an ordered fashion - all the A, B, D, and F keys and none of the others save for the high C. Different manufacturers for the specific keys I guess.


Hmm Interesting hypothesis..
emdot_ambient
FYI, this ebay auction has keyboard bushings at a better price than I've seen elsewhere. Buy Now only for about $30 plus shipping for 62 bushings.

ARP Axxe's take 37, Minimoogs take 44. I've purchased (haven't received them yet) enough for my AXXE and Minimoog and still have 40 some-odd left over. So I'll probably put some up for sale after I get the keyboards upgraded.

Also, I'm not sure if these have the silicone release agent they're supposed to have (Dow Corning 7 Release Agent). If they don't, I'll be picking up some.
valis
Interesting link. I'm pretty tapped out right now as far as expendable cash goes. Let me know if you decide to sell your extra bushings, I'd rather buy them from you than some random ebay seller..
emdot_ambient
Will do. The bushings arrived today and, unlike the more expensive ones, were not lubricated with the release agent, so I'll have to buy some of that.
emdot_ambient
Almost 9 months later...and I finally gave one of my Axxes a bath.

I used distilled water 'cause I have no idea how good my tap water is and preferred not to leave any mineral deposits, and one of these:
http://www.professionaldetailingproducts.com/shop/images/pump%20spraye r%20lg.jpg

I didn't use that exact sprayer, but something very similar. It gave me a very good, concentrated steady stream with more force than a spritzer type bottle like Valis used.

I also pulled the keyboard completely apart, taking off the springs on the back of each of the keys and then removing the key tops. This allowed me to not only change the keyboard bushings, but to clean the whole chassis and each key, which turned out to be a good thing because some of the old dried out nasty bushings had actually stuck to the under side of some of the keys.

ANYONE pulling an Axxe or Odyssey apart to clean the sliders owes it to themselves to take the extra time and expense to change the bushings.

Seriously, the keyboard's action sounds and feels brand new. No clacking, no sticking, no harshness...smooth, responsive, quiet and gorgeous! I'm so psyched!

I still have to lubricate the sliders and clean the keyboard's CV and Gate contacts, and let the PCB dry before I put it back together and see if it actually works any better than before....and if it does, I suppose I'll spring for a new B key top, as one of mine was broken and epoxy'd back together.

I'll post pics when I've had time to transfer them to my PC and resize them.
valis
That's fantastic! I still haven't replaced the bushings in my Axxe but I should as I've been relying on it more and more as a CV controller. You'll definitely have to let us know how it works once you put it all back together..
emdot_ambient
I'll let you know tomorrow.

After putting the keyboard back together I realized that I had actually put the bushings on upside down. There's a top and bottom side, very similar, but different. It only took maybe 10 minutes to pull all the keys off, rotate the bushings and put the keys back on.

I was surprised with the way the bushings fit. It's different than the pics I've seen from other Pratt-Read keyboards. Not all the Axxe models were the same...in fact my 2 MkIII Orange/Black ones have slightly different cases, so I wouldn't be surprised if not all Axxes were like what I just saw. Anyway, with this style keyboard, you have no choice but to pull the keys off to change the bushings. It's not hard to do, all you need is a pair of needle nose pliers and some eye protection (guaranteed you'll lose your grip on a couple of the springs and they'll go off like little rockets).

But, man, after you see the nightmare of the old bushings, you'll marvel that anyone would NOT change them. They feel like a dream afterward.

Can't wait to get my modular going and both Axxes refurbished. I think they'll make great controllers.

[EDIT] Looking back at your picks, Valis, I see the keys on your Axxe are very different than on mine. Yours has a plastic top that screws on over a metal key. With yours, I'd bet that you just have to remove the plastic top (although it might be well worth pulling the metal keys off, too). The one I just did had no metal key underneath, the plastic part was the whole key. The bushings fit inside a square hole that's part of the underside of the plastic key. So there was no way of getting at them without taking the keys off (remove the spring in the back and then slide the key forward until it clears the bushing and the metal arm the bushing's on, then pop it up to disconnect the nylon tab that connects the key to the J-wires that trigger CV and Gate signals).

I'll have pics.
emdot_ambient
OK, update on status:

Well, it worked pretty much.

I had a temporary scare, though, for when I put the Axxe back together and hooked it up, no matter what I did there was a constant note playing. Playing the keyboard would trigger a new note, but as soon as you let go of a key, it would hop right back to the same tone. AND, the top 5 notes seemed to trigger the envelope, but didn't change the pitch....turns out one of the little plastic caps that attach under the keys, the one the J-wires for triggering CV and Gate are attached to, wasn't actually plugged into the key, so it was in constant contact with the CV/Gate bus. And since the Axxe is low note priority, playing the notes above the key in question would trigger the envelope but the CV was held steady. That was a simple fix.

So after that the keys respond correctly and feel great. The sliders are still a little of a problem. They aren't as sluggish as before but seem to stick a bit when you first move them, making subtle changes very difficult. I've ordered some of that 100L slider lube to see if that helps.

BUT, the biggest problem is very odd. When the Release of the envelope is up, the pitch of the oscillator descends at about the same rate as the envelope decreases, even when the slider for ADSR modulation of the pitch is all the way down. None of the other stages of the ADSR have this effect. If I turn the ADSR pitch modulation slider up, then all the stages work as expected, but when it is turned off, only the Release still modifies the pitch!

d'oh! WTF is that all about? very frustrating

I'm working on resizing my pics now and will post some when they're done.
emdot_ambient
OH, and I need to give my ARP Sequencer a bath, too. It may have some serious problems. I tried using it to control the refurbished AXXE...nothing doing. Was having all kinds of problems with that thing.
emdot_ambient
OK, Pics....

Taking off the PCB is a snap. Just remember to take pics or note where each of the connectors goes, and in what direction.

Here's what mine looked like once it had been removed:


Ugly nasty sliders, but not physically in too bad a shape. I bought this AXXE in the late 1980s for like $250...I see signs that it had been opened and serviced (one slider replaced) at some point:


And here's how the sliders looked cleaned up:
emdot_ambient
Replacing the bushings meant tearing down the keyboard assembly:

First thing you have to do with this model of AXXE is to remove the springs on the back of the keys. The red ones are on the White keys, the blue ones are on the Black:

A pair of needle nose pliers does the trick. Just grab the spring on its bottom hook, pull down and ease the spring off. Wear eye protections 'cause they're pretty decent little missiles when you accidentally let one go. STORE THEM WHERE THEY WON'T GO MISSING! I used a snack sized plastic bag for each color.

Next, just move each key forward and up. A bit of muddling taught me that removing the keys (or putting them back on) was pretty easy if you followed this rule: Remove White keys first, then Black ones. When you're putting the keys back on, do the Black ones first, then the White ones. Their shapes kind of lock them so that trying to go sequentially from one side of the keyboard to the next doesn't really work so well.

It's best to keep the White keys in order. The Black keys are all identical, so it's not so important with them. Fortunately, the White keys give you some help if you mix them up a bit. Keys for Dummies:
emdot_ambient
Now on to the bushings themselves:

Here's a shot from under the keyboard before the keys are removed. The red circle shows where the bushings actually sit on this style of keyboard:


Sorry all this pics suck, I've only got this old point and shoot digital and I can't tell where the damn thing's focused without uploading them to the PC.

Here's the keyboard frame with all the keys off:


And this is the mess left on the table just from taking the keys off...those are old dried out nasty disgusting crumpled bushings:


The keyboard frame with the old bushings on:


Bad close up of the old nasty things:
emdot_ambient
Here are the new bushings...

The front, held right-side up. I don't know if you can see, but one of the Y's on the bushing top/bottom is a bit wider than the other, the wider one is the top one:


Side:


Putting the new bushing on...upside down:
emdot_ambient
And some finished shots...

Reassembled keyboard:


AXXE restored...notice how the keyboard has an equal sized bit of metal case on each side of it. My first AXXE (circa 1977 or 78) has a small sliver of case on the right and a wider bit of case on the left (with a small enameled ARP logo glued on it):


Bonus shots....

Filter Module:


And this was kind of cool. I think this is a late model MkIII, for, just like how the case is a bit different from my older AXXE, this one has something different on the bottom: a plastic cover that can be removed to expose the CV/Bus gate for cleaning. Note the little plastic caps that hold the J-wires in place. You have to make sure each of those is attached to its key or you won't be playing much:
Luka
cool post

my friend has being trying to get me to do his odessey for ages and i've avioding it like the plaque. my friends who do synth repairs said that they desolder, open up and clean out each slider. i guess maybe that isnt the only way to go. this seems somewhat do-able.
emdot_ambient
I wouldn't even know where to begin...opening up sliders, etc. First of all, the sliders on this AXXE have metal mounting posts that are kind of flat blades stuck through the PCB, physically twisted to lock them onto the PCB and THEN soldered. There are soldered electronic connectors, too, of course. Assuming I could get them out without damaging them (it's impossible to find replacements unless you buy another synth for parts), then I'd really have no clue how to open them up.

The guy whose video was posted before is a pro synth repair guy. He does it for a living and works on pro musician's gear. He does the wash routine, not the desolder, open and clean routine. I trust him. I don't trust myself opening up one of these sliders! That would be about a $550 mistake if/when I screwed it up.
jarvis
i recently refurbished a friends axxe - i ended up taking all the sliders off, taking them apart, cleaning the contacts, putting them all back together, and soldering them back in. it's a very time consuming process, but the results were worth it. you have to be patient, but it's nothing you can't do if you have a good pair of pliers to twist the panel locks and a 'sold-a-pult' thing to suck out the solder from the terminals.

for what it's worth, i was able to pillage some slider shafts from an old tapco eq we found on craigslist for $30. the sliders looked like they were from the same series/manufacturer (although they had 'tapco' printed on them) as the arp sliders but not the same values so i couldn't just drop them in as replacements. i was, however, able to replace a number of broken slider shafts with them.
schmidtc
Best of luck sourcing that release/pitch problem. Did you replace all the tantalums? The ARP service manuals are more helpful than any other I can think of.

I've restored several ARP machines with these sliders with good results. I bath the whole boards with simple green, iso and a toothbrush, then dry them with compressed air, then lube them with silicon grease. This gets most of the sliders like new, the remaining few get taken apart. Kevin Lightner posted lots of info about this cleaning method on AH and the Moog forum a while back. I think SDIY has some stuff too.

Be careful of that big yellow cap in the bathtub though. That holds the CV for the portamento and they don't like to get soaked too long.
emdot_ambient
OK, just did a bit more testing. The detuning problem isn't the Release. It can't be. The same sympom occurs when the VCA Gain is up (i.e. when the VCA is held open with no keyboard press)

My hypothesis was that it's something in the Keyboard Control Voltage Memory circuit, which also has the portamento slider in it.

It's the value of C13...I'm pretty sure that's the big honky yellow cap... that's supposed to be sampled and held after a key depression. It was sounding to me like after a key depression the sample/hold function wasn't working and the cap was discharging, making the pitch fo the VCO decrease.

However, after playing around with it again a few minutes ago...well, I still think it's in the Keyboard Control Voltage Memory circuit, but I'm not really sure what the culprit there is.

What I discovered tonight was that the pitch that the VCO finally resolves itself to is roughly the lowest F (F# or G) on the keyboard, no matter what transposition you use....AND, when you play a note LOWER than that pitch, the VCO pitch actually RISES instead of falling. Whether rising or falling, it's not an instantaneos change, but rather a slide over several seconds, faster the closer you are to the final resolution pitch.

hmmm..... I'm sure that symptom is pointing somewhere, but right now I'm not sure where.
emdot_ambient
Oh, I do have a copy of the service manual and I have not replaced any components yet.
valis
I've been offline for a while but what a cool series of posts. That was really really great info, emdot_ambient. I'm definitely going to replace the bushings in my Axxe as well. I've been using mine steadily since my first post. Aside from sounding good, it makes a great controller.

As far as your detuning problem, and assuming that I read your post correctly, I'm curious if this problem changes when the physical S&H switch is turned on. Does the S&H circuit function properly? I had a similar problem on my Axxe where the synth detuned itself when the S&H switch was turned on but the S&H wasn't working at all. Another wiggler suggested that I spray contact cleaner on the switch on turn it on/off repeatedly. I did and it worked. The switch was still gunked up from the initial cleaning and was causing problems. I just had spaced that it was the physical switch causing the problem. It'd be nice if your problem would be that easy as well.

Thanks again for such awesome posts!
emdot_ambient
Hmm. I didn't know you had a detune issue as well. It's definitely a quick and easy fix if that's the issue. I'll try that first.

However, the S&H function itself seems to be functioning properly as far as I've tested it.

Still worth a try. I'll do that tonight and let you know if it works.

...and you'll be truly astounded what a difference the bushing replacement makes. Make sure the bushings you buy come pre-coated with the silicone lubricant. I bought some off ebay that didn't have it and had to buy some (Dow Corning DC 7, not inexpensive).

Actually if you get some bushings for your Axxe that aren't coated, let me know and I'll send you some of the gel in a little plastic Ziploc bag. It only takes maybe a tablespoon of the stuff for all the bushings on an Axxe. Put 'em in the baggy with the gel, squish 'em around, Bob's your uncle.

The same bushings are used on any Pratt-Read keyboard (ARP 2600, Odys, Quadra, Omni; Moog Minimoogs, Micromoog, Polymoog, Multimoog, Sonic-6, Satellite; Sequential Pro-One, Prophet-5, Prophet-10; Oberheim 4-Voice, OB-1, OB-SX, OB-X, OB-XA; Octave Cat, Kitten; EML 100, 101). Check online. Not all ARPS and Moogs use them.
valis
That's excellent info as usual, thanks again. I have so many projects right now that I don't know when I'll actually get around to replacing the bushings, but it seems easy enough and extremely useful si I probably should soon.

I hope your problem is as easy as the S&H switch. I am curious if your portamento works the same way as mine does when the S&H is on (i.e. it doesn't really do anything until the portamento slider is 1/2 up and then it just produces one triggered note).

Good luck, it seems like you're in the home stretch!
emdot_ambient
I think my portamento actually does nothing at all when the S&H is on (but works fine when it's off). I was looking at the schematics last night and it looks to me like it should still work...?
emdot_ambient
So I only had time to fiddle around with the synth for a few minutes last night...now the S&H isn't working at all. I'm really hoping this is the dirty switch issue.
schmidtc
Replacing all the tantalums on each board and the electrolytics in the power supply will probably save you some headaches. I'm recapping an omni II right now and it takes forever, but the other Arp machines go quicker. The S&H uses that holding cap for the keyboard CV so it might be a related problem with the portamento issue. Did you try replacing that big yellow cap?
emdot_ambient
No. I've just had time to bathe the PCB and sliders and replace the bushings. That big thing's kind of scary Mr. Green
emdot_ambient
FYI, here's the schematic for the Axxe's S&H, which they call the Keyboard Control Voltage Memory circuit. I've simplified the inputs by just having "Keyboard CV IN" and "Keyboard Trigger IN". Those inputs are actually coming from the S&H switch. The CV IN would actually come from either the Noise Generator or the Keyboard CV Buss, while the Trigger IN would come from either the LFO or the Gate Generator.
emdot_ambient
schmidtc wrote:
Did you try replacing that big yellow cap?

So the schematics just say that cap (C13) is "0.47 10%". Is that .47uF? And I remember seeing it was a pretty high voltage cap, like 1,000 VDC or something. Does the voltage matter?

I was looking on Mouser trying to find a replacement and was thinking one of these might do it: http://www.mouser.com/Passive-Components/Capacitors/Film-Capacitors/Po lypropylene-Film-Capacitors/_/N-5g7uZscv7?P=1z0wquaZ1z0x6d8Z1z0z819

The service manual doesn't even list C13 in the parts list...or any other caps at all except those in the power supply...? hmmm.....
schmidtc
Yep. Guinness ftw!
valis
Definately try cleaning the switch before you go pulling parts out of the machine. From the sound of things I wouldn't be suprised if it was just the switch. If you look at the schematic you can see how the portamento is associated with the CV memory. Good luck!
emdot_ambient
That's me plan. It's just been a suck-ass week and I haven't had a chance to even bring the synth up to my work desk after trying in the studio last time, let alone pull it apart and all.

I like the simplicity of that circuit, though. I'd consider doing a DIY copy of it if I knew enough to find modern substitutes for its more obsolete parts, the 2N3958 in particular. Haven't looked at that op amp to see if there's a readily available substitute. [EDIT] Cool. Just found the LM1458 for $0.15.
emdot_ambient
UPDATE:

Nope, sorry, the pitch problem is not because of the switch. Frankly, I didn't expect it to be after getting to understand a bit more what's happening in the Keyboard CV Memory/S&H circuit.

I actually re-did the whole bath thing just to be sure. I had forgotten to use warm water last time, so I did that, dried everything, blasted the switch really good with contact cleaner and flipped it 20 or 30 times. Then I used 100% fader lube on the sliders.

The pitch problem is exactly as before. The S&H function, however, seems to work correctly.

Here's the deal, though: I'm almost 100% sure the problem is in the C13 cap, or the transistor/op amp part of the circuit. If you look at the circuit above, you'll notice that the cap gets charged from the incoming CV...but ALSO gets charged from a feedback loop from the op amp's output.

That's the "memory" part as far as I can tell. It should be stopping, or at least mitigating, the pitch CV from drooping by feeding its output back to the cap when no incoming CV is present (no key is being depressed).

But what's happening is that when I depress and hold a key, the pitch remains steady. As soon as I release the key, the pitch rapidly decreases until it's near the bottom of the keyboard's range.

Most likely the problem's the op amp. I've got parts ordered. We'll see.
emdot_ambient
So...speaking of parts...I looked again at C13, that big yellow thing, and it's a .47uF, 10% tolerance, but only 100VDC.

My question is: does size really matter?

If I get a replacement that's .47uF and 10% and the voltage is rated at 100VDC...does it matter if it's 10x smaller than the old one? Some of the ones on the Mouser page I linked to are only like 9mm long, rather than the Axxe's 40mm or 50mm or whatever it is. As long as the leads reach the pins, I'm thinking size don't matter.

As for the voltages, I don't think this cap ever gets more than +3VDC thrown at it, so 100, 250, 400, 600+ volts shouldn't really make any difference, right?
Reptil
inspiring thread - have one refurbed axxe and one very nasty one. the nasty one makes nasty sounds - pretty cool actually.
I don't have the space (tiny appartment) to take the synth apart. but I'm working on that.

yeah the caps- modern ones are a lot smaller and better. I think they put that big one in because they didn't have something else that was good enough.
you should check if it's an electrolythic one though and what kind.. if it's paper in oil, leave it.
valis
.. The cap in question..





You can see that I replaced an LM301, which got my noise circuit functioning properly again..
megaohm
valis wrote:
.. The cap in question..






I'd be saddened if I opened up an Axxe or Odyssey and didn't see the familiar big yellow cap.
cry

That's purely from an aesthetic point of view.

Sound or function wise... hmmm.....

p.
emdot_ambient
Well, I've got the parts ordered. I'm going to try replacing the LM1458 first, then the cap...er...um...maybe the other way around.

I just hope one of those works...not really wanting to try and find a 2N3958, they end up being something like $13 or $14 apiece.
emdot_ambient
Wait a minute...have I misread the schematics? Here's a close up of part of the schematics from the service manual...what's that dotted line symbol that I have circled in red?

I've never seen that before, and the connection from above doesn't seem to connect to C13, but rather to the dotted line thingy.

seriously, i just don't get it
Scott Stites
Not having seen the PCB, I'd venture to say that circle is a guard ring. Page 7 of the LF398 datasheet mentions a similar hookup (output of the SH is connected to the guard ring), which seems to be how this configuration is hooked up as well.

http://www.national.com/ds/LF/LF198.pdf
emdot_ambient
Interesting. Never heard of that. Hmm...lemme look...
emdot_ambient
FIXED!

It was just the capacitor. Finally got around to opening it up and replacing the cap.

Replaced it with this one: http://www.mouser.com/Search/ProductDetail.aspx?R=930C1P47K-Fvirtualke y59850000virtualkey598-930C1P47K-F

Even though it's only like 19mm long and 9 in diameter, compared to the original that was something like 40mm X 20mm.

Works perfectly fine now. thumbs up
emdot_ambient
I still have to wonder if there's any advantage or disadvantage to using a higher volt cap, though. Like would it likely hold its tune longer?

seriously, i just don't get it

I'm actually doing a test now to determine how quickly this "CV memory" actually lasts without pitch degradation.
emdot_ambient
Question...does anyone have wiring diagrams for the CV/Gate/Trigger inputs and outputs on the AXXE?

I'm pretty sure the one I'm working on has had them re-wired. When you plug an input into the CV/Gate/Trig it's supposed to pass the signal to the output so you can chain synths in a Master-Slave1-Slave2-SlaveN fashion.

But this one doesn't do that. With no jack in the CV input, the CV output is the 0-3 volts of the keyboard (does not include the transpose). Which is fine. But plug a CV into the input and nothing at all comes out of the Output.

The service manual doesn't show how the jacks are to be wired and I can't find it anywhere on the internet.

The Pedal input's a bit confusing, too. I'm not sure I understand what kind of jack it is just from looking at it. I'd really like to replace all the jacks. They look and feel rather rough.
valis
I do not but if it comes down to it I can draw you a diagram the next time I open up my axxe..
emdot_ambient
Thanks. I'll check my second Axxe. I bought that one after its first owner had only had it a month or so. I know I had to change some of the jacks on it before...hopefully I didn't screw that up!
valis
Good luck! Remember, I have a different revision Axxe so I'm not sure how different the internal wiring would look..
chromium
emdot_ambient wrote:
I still have to wonder if there's any advantage or disadvantage to using a higher volt cap, though. Like would it likely hold its tune longer?

seriously, i just don't get it

I'm actually doing a test now to determine how quickly this "CV memory" actually lasts without pitch degradation.



For hold-type applications, you might look for caps with low "dielectric absorption" ratings. The various poly varieties are usually good choices. I was experimenting with different cap types in a track and hold circuit, and settled on a polystyrene cap.

Nice chronicle of the keyboard refurb, BTW! I did this on my Multimoog a few months ago. Learned the hard way about lube! eek! (bought those dry bushings from the Ebay guy). Man what a difference, though. No more snaggletooth keys, and it no longer sounds like someone is tap dancing next to me when I play it hihi

One other little tid-bit that was interesting to me (and you mentioned this) was the different tension springs for the black and white keys. I never liked the way the keyboard on my Pro-one felt, and when I dug into that one just recently I saw that the springs were all haphazardly installed! I counted them out, and sure enough there was the right number of each tension for both the black and white keys - so after I did the bushings, I re-installed the springs correctly. Huge improvement - no wonder the action was funky all this time! Strange thing is that it was made ~1983, and I bought it like that used around '86. Wonder if it was just a factory goof? In any case, I'm really happy with it now w00t
kindredlost
This thread is awesome.

I did a refurb on my Axxe which is similar to Valis' (black face with gold graphics and the tune knob).

Not all Axxe internal circuitry is the same of course and this was a major problem at first for me. I bought & downloaded a few manuals from online dealers and internet sources. It takes a close look to determine all the model changes.

I had less success with the key bushing fix. I ordered off eBay and at first they helped quite a bit but after a few weeks the keys began sticking again. I may have to try the lubricant. I was under the impression it was lithium lubricant but that may not be the case.

I had a power supply problem at first. A couple of caps later the thing came up fine, but now it is something else. My guess is it is related to capacitors again somewhere in the circuit. The synth powers up properly but there is no sound all of the sudden.

The board bath idea was nothing new for me. For years I have been a service tech at a CNC machine shop which has large boards that were made in the 60's with pre-CMOS technology for the most part. Lots of TTL logic circuits and 90% discrete circuitry. We regularly bathe our boards in distilled water with a mild non-detergent soap (no oily additives) and a soft brush. I usually use compressed shop air at ~80 p.s.i. then gently heat with the hair dryer to remove the last bit of moisture. My main concern is the edge connectors and dip switches. The distilled water really isn't even enough of a conductor to worry about. It s the contaminents in the water that do the damage. We have a $4,000 water distillery in our shop so I have all the pure distilled water I need on tap.

Some of the boards have the resin protectant and this does little to help, but it makes them look cleaner for any desoldering that needs to be done.

The CMOS and later era of integrated circuit boards are where I get nervous. Especially socket IC's. Lots of places for corrosion and poor connections.

The lube spray works pretty well too, but the slider pots have to be very clean before there is a real improvement.

Those slide toggle switches are notoriously flakey after they get old. Mostly it is due to not enough use. Even though they are semi-enclosed the dirt and grime gets the best of them and the contacts get filthy.

I think the cv and gate inputs may be switched. I'll have to bust open my Axxe when I get home tonight to check.

My Axxe was one I bought new in 1980. I had it for a few years and sold it off in a fit of madness. The friend that ended up with it gave it back to me. When I went to pick it up it was in a garage, buried under a sofa couch with a TV set on top of it! It broke my heart as this was the first synthesizer I ever owned. I cordially thanked the person for being thoughtful enough to return it as a gift. What else could be nicer?

-David
chromium
kindredlost wrote:
...but after a few weeks the keys began sticking again. I may have to try the lubricant. I was under the impression it was lithium lubricant but that may not be the case.


That was my Multimoog experience in a nutshell. Some keys took a second to pop back up. The lubricant will get rid of that problem.

Just make sure whatever lube you use is silicone-based (or maybe even teflon-based) and *not* petroleum-based. The latter will have a degenerative effect on the rubber bushings.
emdot_ambient
I made the offer to Valis and I'll extend it to whoever wants it...I've got a huge tube of the lube that was originally used for these Pratt-Read keyboards. It's EXPENSIVE and you really can't buy just a little.

All it takes for the bushings on an Axxe or Minimoog sized keyboard is a tablespoon or two. I'd be more than happy to send some free to whoever wants it...squeeze a bit in a plastic baggy and mail it off. All you'd need to do is dump the dry bushings into the bag and mush it all around until they're coated.

I don't even need paid for postage as long as postage isn't more than a few bucks. Obviously I won't do this for 100 people, but if someone here needs it and doesn't want to hunt the correct stuff down, PM me.
emdot_ambient
In case you want the dirty details...the proper lubricant for the bushings used on Pratt-Read keyboards is Dow Corning 7 Release Compound.

And when I said "EXPENSIVE" I meant like $11 to $15 for a 5.3 oz tube when all I really needed was like a tablespoon or so. Not hugely expensive, but if you only have a small keyboard to fix up, you end up buying way more than you need.

And for all you chemists/material science geeks:
INGREDIENTS CONTAIN: 63148-82-9 Polydimethylsiloxane. 7631-86-9 Silica, amorphous. 70131-67-8 Dimethyl siloxane, hydroxy-terminated.
hmmm.....
kindredlost
I did some more work on refurb of the Arp Axxe. Em_Dot sent me a bit of the Dow Corning lubricant. It helped immediately, then later I saw the sticky keys again. very frustrating

I think I may have the wrong bushings. seriously, i just don't get it Does anyone have a reliable source for the proper ones?

I forgot to look at the cv/gate jacks to see if they are switched or not. I tried to get the thing powered up again and found the -15 v whacked and putting out +5 v. I replaced all the caps and the supply is putting out +15v and -16.4v. I can't get the negative side any closer to -15v than that so I have a couple of power transistors to replace tonight. If that doesn't get it any closer I may have to look into the regulator chip. I don't think it is the pot for that side, but I'm no EE.

Does anyone have a good idea of a replacement power supply for the Axxe? Just in case.

-David
emdot_ambient
When you replaced the bushings did you take the keys all the way off and clean the chassis, keys, key tops (if any) and all that? It's clear that the older Axxes had a different keyboard build than the newer ones like I have. For starters they have metal keys with plastic key tops, and the newer ones have all plastic keys, no separate top that attaches to metal keys with a screw.

I ask because on Minimoogs it's possible to change the bushings without pulling off the keys. I don't recommend doing that because you may not be able to get rid of all the old bushing gunk. Also, the Minimoog's Pratt-Read keyboard has another part similar to these bushings that could need replaced or at least cleaned and re-lubricated...it's called the bellcrank cap. You can see them in this shot (the yellowish caps on top of those white things: http://www.flickr.com/photos/31603983@N05/3454217306/in/photostream/

I don't know if the older AXXEs used this kind of Pratt-Read keyboard or not...my newer ones don't. If they DO...that's another thing that might cause key sticking.

Here's another site that has some info on Pratt-Read keyboards (though it's talking about ones used for organs, I think it's still valid): http://www.users.cloud9.net/~pastark/sonote56.htm

Quote:
A message on our Web Page reads in part: "The keyboard keys will get very stiff to push after a day or two of inactivity. The longer the stiffer. I run up and down the keyboard a few times and then they are smoother again. More and more are getting clackity..." I also ran into sticky keys, and found it to be the grease in the channels. After many years, in some keyboards, the grease has hardened, sometimes the bellcrank elbow caps (or bushings) are worn. This is a relatively simple problem to correct. Remove the key caps. Remove the key return springs. Then remove the key channels. Be careful not to loose the bellcrank caps, they may stay on the bellcrank, or they may stick in the grease in the channel. Take all the bellcrank caps and clean off the old grease. Clean all the old grease out of the key channels. Now replace the caps and grease them liberally. Replace the key channels, springs and key caps. If a key does not feel right, check to make sure the bellcrank cap did not slip off. Note that the white (natural) keys use a silver colored key return spring, the black (sharp) keys use a blue colored key return spring. I phoned Mr. Woody Comstalk, president of Pratt Read & Co. to ask him if he remembered what grease was used on the keyboards his company manufactured. He did not remember. To the rescue came Ray DeVault of DEVTRONIX, the same man who rescued Schober owners who had not completed the purchase of kits when Schober folded. He gave me the name of an outfit that sells the grease and the bellcrank caps. ORGAN SERVICE CORP. PO Box 372, Marengo, IN 47140-0372, (800) 457-4408. The grease is D-C #7, item 642-002-00, 5.3oz. $15.95, The bellcrank caps (also called bellcrank bushings or key bushings) are item number 72320-264, $.20 each.
emdot_ambient
As for power supply...no clue what the amps are on that thing. Other than that I would think that any +15/-15 VDC linear supply would work if it fits in the case.
Synthbuilder
kindredlost wrote:
... then later I saw the sticky keys again. very frustrating


I replaced the bushings on a MkIII Odyssey a couple of months ago. I did the first octave and put the key tops back but I noticed a stickiness in the key actions that I never normally get. The bushes are pre lubed and come from Rich at Arcsound. They've always been very good so I looked into why they didn't work so well this time around.

I don't think it's the bushes. Well, at least the bushes will work just fine with just about every other P&R keyboard you may have. The thing is on this ARP the tangs that the bushes slide onto had been pressed too flat with a circular punch. A lot of P&R tangs have this flattening of the top but this ARP had wider and flatter tangs than normal. Thus when the bushes went on they were forced to be wider than they should be. This caused the sticking of the keys. Perhaps P&R used thinner bushes in later years and maybe had to flatten tangs accordingly?

Solution: removed the bushes again and filed down all the tangs so that they were of the same thickness from the stem to the ends. With a decent needle file it took me no longer than 30 minutes to do the whole keyboard. Once the bushes went back on the keyboard was perfect.

Tony
Synthbuilder
kindredlost wrote:
Does anyone have a good idea of a replacement power supply for the Axxe?


No need to replace it. It'll be something simple. Try replacing the two 10K resistors, R8 and R12, first.

Also, pull out the output power connector to the PSU and test the voltages with it off load. Do you now get +/-15V? If so, it could be the power device Q5.

I don't need to tell you that the ARP power supply has way too many exposed parts running at high voltage. So do be careful.

Tony
kindredlost
Quote:
Solution: removed the bushes again and filed down all the tangs so that they were of the same thickness from the stem to the ends. With a decent needle file it took me no longer than 30 minutes to do the whole keyboard. Once the bushes went back on the keyboard was perfect.


I'd thought about that but considered it a last solution. I make metal parts for a living and believe me it's much easier to remove steel than replace it. I'll definitly do this. The sticking is while the keys are UP. Some are slugginsh no matter how much lube I give them. Slow action.

The resistors were my next fix. I already replaced the Q5 as a first try. With or without a load there is still a minimum of -16.2 volts off the negative side.

The manual for calibrating the supply says to check positive polarity and set it first, then reverse the leads to ground and -15v to check for +15v again. I think this could be sue to an older method using a VU Meter style voltmeter. Anyway, the resistor idea sounds likely because of the need to reduce the -15v side obviously isn't working. That is what they balance through Q3 (if I read the circuit right).

At a hazard of straining the goodwill here, I do have another general query about the octave rocker switch calibration. According to the manual you can only adjust the upper setting to get it in tune with the middle setting. I can get this fine but then the lower range is sharp by just less than a quarter tone. I can get both high and low ranges the same but I cannot figure out how to make all three ranges closer. Is there another pot to calibrate or am I creeping into the main board repair region? eek!

Thanks emdot_ambient and Synthbuilder for all your help recently. Guinness ftw!

-David
kindredlost
Complete success!

The resistor change made the -15v power side calibrate in nicely. Right in the middle of the pot.

The bushing pegs were 0.14" wide and I filed them down to 0.13" and straightened all of them with a square and straight edge before reassembly. This proved to free up the sluggish key action very nicely.

Once the power supply was right the calibration of octaves went smoothly. The thing plays like new now. I forgot how good the Arp Axxe sounds. It really is a classic sounding synth and the very best of the mono-oscillator synths. Very stable oscillator.

I may go ahead with a midi kit by Synhouse now. Has anyone done this retrofit? It looks pretty easy.

http://www.synhouse.com/axxe1.html

-David
emdot_ambient
I've considered that MIDI retrofit also. Only thing I'm a bit skeptical of is my ability to do the holes in the case without messing up the synth visually.

Now on my issues...

1) I checked the power supplies on both my Axxes and was able to calibrate the one I've refurbished to +/-15V no problem. The one I have yet to work on, however...I got the -15V set but when I checked the +V I found that, though it's reading +14.99V....adjusting the trimmer has NO effect at all. As in, turn the dial as you like up or down and nothing happens. Do they even make a trimmer like that anymore?

2) I've done some measuring on the CV out jack of the one that's been (somewhat) refurbished and I'm not getting the 0V to +3V I'm supposed to off the keyboard. I'm actually getting +0.01 to +2.97V.

I'm wondering if it's something as simple as a resistor in the Keyboard Current Source circuit. That circuit's supposed to feed the keyboard with its High (+3V) and Low (0V) CV, which are then passed through 36 100 Ohm resistors (resistor arrays actually? There's no schematics for the actual keyboard circuit in the servicing manual) to get the correct CV off each note.

Further tests show something that's probably significant, but I'm not sure exactly what it means: High C has a voltage of +2.97V, which is +.03V too low. The next lower C, which should show +2V is actually showing +1.98V...+.02V too low. One C lower, which should be +1V is showing +.99V....+.01 volts too low. Bottom C, however, is +.01V too high.

It's just kind of odd and probably not randome that I'm seeing a voltage error of +.03, +.02, and +.01 on the different octaves.

It's a very simple circuit....?

Actually the resistor value on the left is a bit unclear on the manual's schematics. They're both 1% reistors, too.
emdot_ambient
Yep, got the resistor values correct in that. 39.2K and 33.2K. Looked at the PCB just now and with a magnifying glass I can read it written right on the resistors....

....only thing is, when I check the actual resistance coming off them, one's reading 17.69K and the other's reading 17.59K.

I don't know the math of these things. Why'd they use the 2 resistors like that?

Oh, and the high voltage going TO the keyboard from that circuit is actually 2.97, so the issue's definitely in the circuit.
daverj
If the two resistors are in parallel, then it's odd that you got different values when reading each one. They should read exactly the same value.

A 39.2K and a 33.2K in parallel calculates to 17.976K. (if they're 1% resistors then it could be between 17.798K and 18.155K) When tested in circuit the reading might be a bit different because of other components in the circuit. But both of them should read the same, if they're in parallel to each other.

The reason for them to read different could be:

- bad solder joint or corroded trace between them
- loose lead on the meter
- poor connection between meter lead to component lead when reading them
- old battery in meter, so values change over time

You might replace the battery, and then when doing the reading rub the probes on the component leads to make sure you get through any oxide on the leads. If they still read different then I'd check the circuit to make sure they really are in parallel, and to see if the solder joints look good.

One reason a design might have two resistors in parallel is if the target value needed is not a standard resistor value. Putting two in parallel lets you come up with all sorts of non-standard values. Another reason is to increase the wattage.

The other thing to consider is that 2.97v is only 1% off from 3.00v. Many digital volt meters aren't accurate enough to guarantee that 3.00v will actually read 3.00v
emdot_ambient
Thanks for the info! I hadn't even thought about the reading actually showing the parallel value. Makes a lot more sense, though.

I'll look into the battery thing. I think my meter's a Fluke 73-III. I'm not sure the exact model, but it's rated at something like .01VDC accuracy and was supposedly calibrated in the past year. It consistantly shows 2.97, 1.98, .99 and .01 volts on the octave outputs.

I was hoping to use the Axxe's keyboard CV out for some calibration on DIY VCOs, but the current readings would give me -12 to +36 cents off true note value.
IvanC
Arp Axxe's, and a lot of other synths of their vintage, have a bunch of tantalum capacitors that are time bombs. They tend to short when they go bad. I highly recommend going through and replacing all of these before they short and cause damage.

Ivan
frax
Hi!

I have an Axxe and an Oddy im about to freshen up a little and both of them have quite a few sliders broken of.

What options do I have to fix this?



/frax
dougt
I have some of the slider shafts. You will need to desolder the sliders, carefully open them up and replace the shafts.
frax
dougt wrote:
I have some of the slider shafts. You will need to desolder the sliders, carefully open them up and replace the shafts.


PM!
emdot_ambient
After you desolder the sliders, here's a video that shows how to open them up...I haven't tried it but it looks pretty easy:

http://www.youtube.com/watch?v=LpiB5EBB5wo
jarvis
it's very easy to do the shafts, just make sure you don't bend the metal tabs too much. i think they're iron & they seem like they'd snap after a dozen bends or so (which you shouldn't even get near). I just used a q-tip & deoxit on the swiper/resistor plate to clean off the gunk. Might be a good idea to get some fader lube too, but I didn't have any on hand at the time when I did mine
dude
anybody know of where to find the plastic arp slider caps?
valis
Apparently you can still order them from places like Mouser. Check this out:

http://www.marksmart.net/gearhack/arpomni/slidercaps.html

There is a little additional work needed apparently though..


For archival purposes:
Quote:

PART
NUMBER COLOR
-------------------------
10TB001 RED
10TB002 BLACK
10TB003 WHITE
10TB004 BLUE
10TB005 YELLOW
10TB006 GREEN

sanders
dude wrote:
anybody know of where to find the plastic arp slider caps?


You can buy the original tipped slider caps from Mouser; for a long time they carried all of the same colors except white (?), but now, I think they only have 2 or 3 colors available. They're a very tight fit at first, you have to kind of stretch them out or heat them with a hair dryer.

I'm sorry, I don't recall the part number, but I ordered some myself less than a year ago.
dude
i have some leads on the gummy rubber ones from small bear but i was hoping for the hard plastic molded ones that were used on later models (orange) i think.
emdot_ambient
I wouldn't want the hard plastic ones. Mine started falling off within a year of buying my AXXE back in 1978!
dude
emdot_ambient wrote:
I wouldn't want the hard plastic ones. Mine started falling off within a year of buying my AXXE back in 1978!


well while i DO want the arp ones, i see they are very hard to come by. anybody got any leads for any slider caps other than the soft rubber ones?
dougt
I have a few of the wider, hard plastic ARP slider caps for $10/ea. Not cheap but cheaper than the guy on ebay charging $19/ea.
dude
dougt wrote:
I have a few of the wider, hard plastic ARP slider caps for $10/ea. Not cheap but cheaper than the guy on ebay charging $19/ea.


nah that is ridiculous.

i have given up looking for arp style caps and and am on to looking for any caps that might work.
jarvis
'bout time to bring this thread back to life.

I just had my Axxe shipped back to me from a friend and the power transformer ripped out of the power supply pcb in transit zombie They must have dropped the package from the plane to my doorstep...

So, I need to redo the power supply, but can't get exact specs on the transformer. It appears to be the same transformer as the early Odyssey and the Sequencer. By the schematics, the +15v rail comes out of Z1 which is a U6A7723 vReg rated at 150mA, so I'm assuming that's the max current available to the synth. Please correct me if I'm wrong!

I was looking at this Hammond 186C56 as a replacement – 56vct @ 210mA. Can anyone see anything wrong with this or should I bump up to a higher current transformer?

Another option is to just throw a Power-One HAD15-0.4 linear supply in there since you can get them so cheap on ebay, but it would require mounting the shield sideways to the Axxe chassis since it's too wide (4.25" vs the current power PCB @ 3"), which I would be concerned about bending the chassis over time due to the weight of the HAD15-0.4 (2.2lbs).

Another option all together would be to get a power supply board on ebay (like this one) and an appropriate transformer for that. Since there are techs out there that offer power supply upgrade kits, maybe its not a bad thing to beef up the available current for the synth?

Any tips are much appreciated!
Graham Hinton
jarvis wrote:

I just had my Axxe shipped back to me from a friend and the power transformer ripped out of the power supply pcb in transit zombie They must have dropped the package from the plane to my doorstep...


Sorry to hear that, but that's why mains transformers should not be mounted on a pcb.

Quote:

So, I need to redo the power supply, but can't get exact specs on the transformer. It appears to be the same transformer as the early Odyssey and the Sequencer. By the schematics, the +15v rail comes out of Z1 which is a U6A7723 vReg rated at 150mA, so I'm assuming that's the max current available to the synth. Please correct me if I'm wrong!

I was looking at this Hammond 186C56 as a replacement – 56vct @ 210mA. Can anyone see anything wrong with this or should I bump up to a higher current transformer?


Don't use that, the voltage is far too high.
The ARP PSU wants about 28V on the reservoirs so an 18-0-18Vac will be fine.
You will probably find that a dual secondary is easier to source, just join the secondaries in series observing the phase. Although a 723 is used there is an external pass transistor. The ARP PSUs are current limited to 180mA on +15V and 150mA on -15V so you need at least a 15VA transformer, 30VA would be enough. I would use a toroidal type mounted on the base and a fused IEC inlet so that you don't have any exposed mains on the PSU pcb.
jarvis
Thanks, Graham!

So this Triad transformer should do the trick? 25VA, dual 18v secondaries.

I think the breakaway of the transformer happened on the very last leg of the trip, as there is – thankfully – no other internal damage due to the transformer rattling around. That could have been very, very ugly...
Graham Hinton
jarvis wrote:

So this Triad transformer should do the trick? 25VA, dual 18v secondaries.


Yes. That type is made by many companies internationally so there will be no problem if you ever need to replace it. As this one has stranded leads (some have the windings brought out--avoid those) you can crimp 1/4" fastons on each lead and repurpose the four faston tabs on the pcb, link them to where the secondaries were soldered in.

btw, I have an Axxe pcb cannabalised for parts. If anybody needs the rare Transpose or Keyboard Repeat switches PM me.
sneak-thief
Re. toroids in Arps:

I replaced a burned out transformer on a MkIII Odyssey last month (it was set to 110V and someone gave it 240V - the fuse didn't save it).

Anyhow, the inrush current of a larger toroid spiked above the original spec'd 1/8A fuse and would blow it. You might need a larger fuse or slow-blow to prevent this (as I did).
onewheeltom
Just received an Arp Axxe (first gen) in the mail from a friend. Picture is attached. Have opened it up, but not powered it on. It was in an Anvil road case with this deteriorating blue foam. I've blown out much of the gunk. The sliders do not move.

I'm thinking first, give the PCB and keyboard a bath and dry. Then test the power supply before re connecting it to the PCB. Any other precautions to take before powering it back on? Sounds like I should have some slider lube on hand before I give it a bath.

This thread is awesome. Lots of great info.
schmidtc
nice axxe! moog filter! never understood why there's bad teeth in the keys of these, seems they'd all age the same. prob best to give it all new big and small electros in the power circuits and then bath it. watch out if there's a big paper tho, don't take kindly to water. really really hot water then a bit silicone lube should get the sliders moving.
jarvis
I have the same 2810 model with yellowed keys but I was able to get rid of most of the yellowing. The base plastic is still slightly off-white so they don't all perfectly match, but it's still a hell of a lot nicer to look at!

I just followed the tips from this video:


I don't have a UV lamp and it's been cold/overcast in Chicago so I was not able to set them outside in the sun, however a few days by the window worked just fine. I used a pyrex baking dish, a 90¢ paint brush from Home Depot, a 4oz bottle of the Sally Salon Creme (~$2), and some plastic wrap.

Take the yellowed keys off the Axxe, wash off the grime, set them in the pyrex dish, coat them liberally with Salon Creme using the cheap paint brush, then cover the dish with plastic wrap so that the creme doesn't dry out so fast. Set it by the window and in a few days your keys will be nearly white!
onewheeltom
Disassembled and gave the Arp a bath : first Simple Green, the rinse with warm water. Was not that dirty but cleaned up even better. Tested the power supply, everything good so far.

I started to take the keys off, but wasn't sure how to do this without damaging the springs. The action seems pretty acceptable to me so I will probably leave it alone for now. I noticed that the plastic key covers were held on with screws, so I may take them off to clean.

Ordered the fader lube, should have it next week.

--tom
Silflay Hraka
Pretty good tutorial here, starts dissecting the keyboard at around 4:00 minutes, just substitute Axxe for Prophet 5 (both use Pratt-Read keyboards)



good luck and have fun with the restoration.
emdot_ambient
If the sliders are actually completely stuck, I'd seriously consider rebuilding them rather than just bathing/lubing.

I did the bathe/lube on one (see earlier in thread) and the sliders still don't work like they should. And mine were merely stiff prior to cleaning.

The Real MC
Had a bad 100K lin slidepot in my ProSoloist. The rubbing alcohol did a good job cleaning it, but the carbon on the resistive strip has worn off. It no longer measure 100K, it is an open circuit. The pot is shot.

I tore out the other slidepots and replaced them with rotary pots. That was a bit of a challenge because the pads and traces were lifting. I don't want to dig in there every time one goes bad and I'm tired of hosed slidepots, if one has failed then the rest are not far behind.

Never buying an ARP or any gear with slidepots again. They are a PITA.
el-bee
Back in 2007 I did a full slider clean up & other restoration works for Arp Odyssey. Wrote about the process on my DIY blog, the slider post is accessible through the Odyssey project page.

As I'm currently doing a TTSH build, I'm thinking of comparing how its sliders might fit work mechanically for the Odyssey (= Lumina mod). Dunno, perhaps getting some batch of adapter PCBs could work for that smile
Don T
el-bee wrote:
Back in 2007 I did a full slider clean up & other restoration works for Arp Odyssey. Wrote about the process on my DIY blog, the slider post is accessible through the Odyssey project page.

As I'm currently doing a TTSH build, I'm thinking of comparing how its sliders might fit work mechanically for the Odyssey (= Lumina mod). Dunno, perhaps getting some batch of adapter PCBs could work for that smile


I've got a set of adapter boards drawn up already cool



I'm in the middle of (read: stopped to work on a bazillion other things also) installing a set in my Axxe.
Stewart Pye
Don,

I was thinking about doing the same thing for my Axxe, and putting a little 5V switchmode supply in it to power the LED's.

Please let us know how it all line up when you get it finished...

Regards,
Stewart.
el-bee
Don T wrote:
I've got a set of adapter boards drawn up already cool


Cool, figured someone might be on it already! smile Any plans to make a board kit available for order?
Don T
Stewart Pye wrote:
Don,

I was thinking about doing the same thing for my Axxe, and putting a little 5V switchmode supply in it to power the LED's.

Please let us know how it all line up when you get it finished...

Regards,
Stewart.



el-bee wrote:
Don T wrote:
I've got a set of adapter boards drawn up already cool


Cool, figured someone might be on it already! smile Any plans to make a board kit available for order?


Not sure how long it will take, getting things lined up with the slots in the control panels is tedious. The ARP OMNI filterboard in the pic is never going to be anything other than a module tester, and never will be mounted behind a panel, so of course it was easy.

I'm also working on doing these for another synth at the moment, so going back to the AXXE may not happen this month.

Not sure anyone would be interested in individual adapters?

I've also got these drawn up to replace the sliders in the real ARP 2600, or any other thing that uses those sliders.
el-bee
Don T wrote:
el-bee wrote:
Don T wrote:
I've got a set of adapter boards drawn up already cool


Cool, figured someone might be on it already! smile Any plans to make a board kit available for order?


Not sure anyone would be interested in individual adapters?


One option might be to add the board to OSHPark, then everyone interested could just order their preferred amount of boards.

I have no experience on how much of a hassle it is to add a board to OSH, but judging by how much people use it here at Muff I'd guess it's a breeze smile
MrRoper
Hi guys! Didn't know whether to start a new thread so I just thought I'd tag my questions on the end of this one.

Anyway, I'm just starting up on an ARP axxe restoration. Full re-cap, fader rebuild and keyboard rebuild. One of the faders (ADSR VCA level) has a broken shaft, does anyone in the UK/EU have a source for either a replacement shaft or a replacement pot? I believe it's a 1MA.

I'm also looking for fader caps if anyone has a source? I was thinking to ask Korg for a sample from their mk3 odyssey. Has anyone tried them to any degree of success on the original faders?

Thanks a lot in advance chaps!! thumbs up

Dan


modularrydavid
Really late reply, but I took a CTS slider into a shop with a new MK. III Karp Ody and no, the fader caps don't fit. I don't know if they could be hollowed out further to fit the shafts, OR if somehow the Ody FS will have different caps. Kinda doubt it, I have a feeling the CTS pot shafts are always gonna be slightly different than any of the new pots shafts.

MrRoper wrote:
Hi guys! Didn't know whether to start a new thread so I just thought I'd tag my questions on the end of this one.

Anyway, I'm just starting up on an ARP axxe restoration. Full re-cap, fader rebuild and keyboard rebuild. One of the faders (ADSR VCA level) has a broken shaft, does anyone in the UK/EU have a source for either a replacement shaft or a replacement pot? I believe it's a 1MA.

I'm also looking for fader caps if anyone has a source? I was thinking to ask Korg for a sample from their mk3 odyssey. Has anyone tried them to any degree of success on the original faders?

Thanks a lot in advance chaps!! thumbs up

Dan


MrRoper
Thanks for the reply! I think I'm going to abandon the idea of getting the mark 3 caps because

I'm going to go with those mountain switch caps like the mark 1 has, but get them all in red as it goes quite nice with the black/ orange panel. It's nearly there now just trying to find a source for pratt reed bushings in the uk.


windspirit
Hey folks, fixing up an Axxe mk2 for a client, already getting a lot of value out of this thread!

So I am pretty much in the home stretch for getting this thing 99% working again but I have been foiled by a very frustrating nemesis: no one sells the key return springs for the black keys on mk2s any more! I looked everywhere and I just can't find them. I know that different springs yield different tensions and that can change the feel of the instrument so I would prefer to get the correct springs if possible.

From some searching around it seems that the Sequential Pro One used the same keyboard as the axxe mk2, unfortunately the mk1 used a different keyboard (although from the same manucturer - pratt read, so maybe the same springs) but I also can not find these springs for the Pro One. Does anyone know of another keyboard that used the same springs or at least ones with similar enough tension? Maybe it would work to just get white key springs and stretch them out a bit?

Thank you for your help!
limpmeat
Don T wrote:
el-bee wrote:
Back in 2007 I did a full slider clean up & other restoration works for Arp Odyssey. Wrote about the process on my DIY blog, the slider post is accessible through the Odyssey project page.

As I'm currently doing a TTSH build, I'm thinking of comparing how its sliders might fit work mechanically for the Odyssey (= Lumina mod). Dunno, perhaps getting some batch of adapter PCBs could work for that smile


I've got a set of adapter boards drawn up already cool



I'm in the middle of (read: stopped to work on a bazillion other things also) installing a set in my Axxe.


This is exciting, I have MK2 Odyssey that I'd love to do this retrofit to.
dougt
windspirit wrote:
Hey folks, fixing up an Axxe mk2 for a client, already getting a lot of value out of this thread!

So I am pretty much in the home stretch for getting this thing 99% working again but I have been foiled by a very frustrating nemesis: no one sells the key return springs for the black keys on mk2s any more! I looked everywhere and I just can't find them. I know that different springs yield different tensions and that can change the feel of the instrument so I would prefer to get the correct springs if possible.

From some searching around it seems that the Sequential Pro One used the same keyboard as the axxe mk2, unfortunately the mk1 used a different keyboard (although from the same manucturer - pratt read, so maybe the same springs) but I also can not find these springs for the Pro One. Does anyone know of another keyboard that used the same springs or at least ones with similar enough tension? Maybe it would work to just get white key springs and stretch them out a bit?

Thank you for your help!


How many black key springs do you need? I think I still have some.

By the way I have original CTS slider shafts too.
emdot_ambient
MrRoper wrote:
...now just trying to find a source for pratt reed bushings in the uk.


I got mine from ebay but they didn't have any release agent (aka lubricant) on them. And you really should use the correct release agent (Dow Corning 7 Release Agent is recommended and it's expensive) or they won't work well.

As I offered earlier in this thread, if you get dry bushing (I have seen bushings in the past advertised with the lube already on them) and need some release agent, let me know and I'll put a squeeze of it in a plastic bag and send it to you. Put the bushings in the bag and mush them around, works a treat. As long as shipping's less then a couple USD, I'll even pay shipping 'cause I bought a huge tube of the stuff back when I did my Axxe and still have 99% of it left.
MrRoper
Thanks for the info mate! I actually have a HUUUGE tube of DC 7 that I've been using on Pratt Reeds for the last year or so now. It's just getting the bushings this time (my UK source is showing as sold out atm), I can get some sent from Holland (www.ep-service.nl fwiw) but shipping is sometimes quite steep.

If anyone in the UK/EU needs some of the Dow Corning lube I can send some to you as emdot offered.
windspirit
Hi folks, Im in the home stretch here.

I recalibrated the oscillator 1v/o behavior relative to the keyboard but after testing noticed that a) the octave switch no longer changes the pitch by an octave and b) incoming cv is no longer 1v/o. Is there a separate calibration trimmer for the keyboard rather than CV? Thank you!
Don T
windspirit wrote:
Hi folks, Im in the home stretch here.

I recalibrated the oscillator 1v/o behavior relative to the keyboard but after testing noticed that a) the octave switch no longer changes the pitch by an octave and b) incoming cv is no longer 1v/o. Is there a separate calibration trimmer for the keyboard rather than CV? Thank you!


Oh yes, there are quite a few to check:

R62 - Transpose Calibrate
R198 - CV Offset
R76 - VCO Freq
R74 - VCO V/Oct (Which you have found already)

It wouldn't be a bad idea to check R70 - Pitch Bend Calibrate. If you have a MkII Axxe (Orange graphics and PPC, it doesn't have this trimmer)
windspirit
I have the mk2, so I have actually gone through all of those trimmers in hopes that it would fix my problem. I found the transpose calibrate and got the tuning to go down an octave accurately but not up an octave confused. Still no v/o calibration either. At least the trimmer is accessible from the front panel but I am halfway considering adding a new trimmer just for the keyboard.
Don T
windspirit wrote:
I have the mk2, so I have actually gone through all of those trimmers in hopes that it would fix my problem. I found the transpose calibrate and got the tuning to go down an octave accurately but not up an octave confused. Still no v/o calibration either. At least the trimmer is accessible from the front panel but I am halfway considering adding a new trimmer just for the keyboard.


Just curious, did you calibrate the trimmers in the order described in the service manual, and with the front panel controls set as it suggested?
windspirit
I did the first time but Im at home right now trying to get the calibration right and I don't have my tuner handy.
MrRoper
Finally finished and trimmed my Axxe. It's sounding great and feeling better now the faders actually move and they keys are straight!!

Thanks for all the great info on this thread!



[/img]
Polymooger
Hi folks. I've just given my Odyssey sliders the KL shower treatment and whilst they're freed up a lot they're still crackly, especially filter cutoff. I'd previously and naively used Deoxit on them which per the stories proved to be only a passing fix, and boy did that stuff turn to glue after a few years. Horrible.

Anyway I'm thinking maybe I might replace the sliders. Are the only suppliers still Synthpatchers and Synthchaser in Canada/USA? Anywhere in Europe do them?

What's the consensus on Synthpatcher's version? I've read they aren't brilliant (and are thus faithful to the originals!).

Oh I know about the CMS Lumina kits but they're mental money to me.

Cheers.
Dr. Sketch-n-Etch
(This is in a different thread, but...) I bought an Odyssey that was in pieces for $350 from a guy who found it in a "hoarder house" with a bunch of other garbage (his wife is a realtor) and was hesitant to let it go but realistic that he was probably never going to get it together properly. I gave the innards a bath with warm soapy water in the kitchen sink (we have one of those detachable spray heads, which came in super handy). The whole thing was completely filthy, especially the sliders.

I was also very unhappy that I couldn't separate the power supply from one of the boards because it was wired directly to it, so I de-soldered those wires, drilled a few holes, and installed an MTA connector so I could unplug the power supply from the board. This made things much easier. I also cut and reinstalled the power cord, which was very frayed around the grommet.

Two sliders were broken off at the base, so I replaced those (a very kind Wiggler sent me three replacement white slider doo-hickies gratis). I hit all the sliders with Fader Lube and they feel pretty good now. I would not advocate taking every fader apart, because it is very easy to break the plastic on the ends when removing those metal clips. Just give them a good sluicing out with warm soapy water, Q-tips, whatever, let them dry thoroughly, then lubricate them well. They'll be fine.

Also, the panel had been written on in pencil all over, and had the remains of a big sticker on it. I hit the sticker with alcohol and it came off easily. The rest cleaned up very well with a bit of baking soda in water. The printing was not damaged at all.

Finally, the keyboard was very sticky and somewhat uneven, so I bought a bushings kit from Synthparts ($40) and installed those. Now the keyboard feels like new and is almost perfectly even. This also gave me the opportunity to really clean each key thoroughly with rubbing alcohol, so they are as clean as new (this thing was really filthy, and covered in cigarette smoke).

I took the finished unit over to a buddy's who has owned every synth ever made, and he assured me that it was working and sounding like a factory 2800 white-face. Best $350 I ever spent.

The only problem with the Odyssey is that I could never get the plastic case reinstalled the same way. It is very hard to take it on and off. I bought new screws, and only installed them in about half the holes. I also bought some felt feet for it, because otherwise it was resting on metal screw heads, which would damage any surface it was set down on.

Now all I have to do is replace the broken octave selector switch. I have one on the remains of an old Soloist (that is beyond repair) that I can use. I just haven't done it yet.

Having said all that, the Odyssey is rather a shitty synth, if I don't say so myself. I am tempted to build a new one using all my own circuit designs, with proper duophony. The duophony on the Odyssey is more of an inconvenience than anything, since it doesn't really work the way you'd expect, and the synth could use a lot more modulation options. I'm really envious of the Sparta synth (although I'd want a proper keyboard). That dude did an amazing job.
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