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Befaco Rampage build
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Author Befaco Rampage build
revel8or
Hey all. I've ordered the PCB and the panel from Modular Addict. It looks like everything is pretty easy to source - except for the 6 gang pots and the slider(s) and switches. I know that Befaco has them in stock, but I was wondering if anyone has found them in the states.

I think that I've found the appropriate dual gang pots and slide potentiometers at Mouser. The Mouser p/n's are:

Dual gang potentiometer: 652-PTV112-4420AB103 (the Bourns PTV112-4 has a "6 in a row" connection, but I'm not sure if it is the correct physical size)

100k linear slide: 652-PTA3432010CIB104

Has anyone tried these instead of the parts from Befaco?

Also: the BOM calls for a two position switch for the cycle, and a three position switch for the range. Is the three position switch an "on-on-on" switch, or is it "on-off-on?" Again, has anyone found a stateside option for the range switch?

I've downloaded the BOMs that have been created by nevetsokyeron, et al., and it would be great to source these here in the US to add to that list.

Thanks a lot!
fuzzbass
revel8or wrote:
Hey all. I've ordered the PCB and the panel from Modular Addict. It looks like everything is pretty easy to source - except for the 6 gang pots and the slider(s) and switches. I know that Befaco has them in stock, but I was wondering if anyone has found them in the states.

I think that I've found the appropriate dual gang pots and slide potentiometers at Mouser. The Mouser p/n's are:

Dual gang potentiometer: 652-PTV112-4420AB103 (the Bourns PTV112-4 has a "6 in a row" connection, but I'm not sure if it is the correct physical size)

100k linear slide: 652-PTA3432010CIB104

Has anyone tried these instead of the parts from Befaco?

Also: the BOM calls for a two position switch for the cycle, and a three position switch for the range. Is the three position switch an "on-on-on" switch, or is it "on-off-on?" Again, has anyone found a stateside option for the range switch?

I've downloaded the BOMs that have been created by nevetsokyeron, et al., and it would be great to source these here in the US to add to that list.

Thanks a lot!


Befaco modules I built (BF22 and Rampage) involved enough non-stock parts that I went ahead and ordered full kits. Deal breakers for me are usually sliders, colored knobs and 1/8 watt resistors. Sorry, I know this helps you not a bit.
Sin_Phi
The range switch is an on-off-on. That is the right dual gang pot. See this thread https://www.muffwiggler.com/forum/viewtopic.php?t=165307 (oh looks like you might have already)
LSuveg1
Apologies in advance if I'm hijacking this thread inappropriately; I'm new here. I successfully built some of a Befaco Rampage. That is, the "output a" doesn't seem to work, despite its LED lighting sporadically. I've reflowed a lot of solder joints, verified that the ICs are seated in the correct orientation, but I'm at a loss as to how I should proceed. I've emailed Befaco but haven't heard back in a week (and I understand that they're a small company).

So, I guess my question is -- how would you proceed if you encountered this issue? I've got a multimeter to check the voltages, and a scope to calibrate the waveforms (which are as expected on channel "B"). The only obvious damage to the board is the solder pad where the large right lug of the "cross fade" pot attaches (i burned it while removing a damaged pot).

Thanks to anybody who can point me in the right direction! This is my third build after a synthrotek/MST output module, Turing Machine MKII and Volts Expander, all of which work normally without issues.

[video]https://youtu.be/LocQIimE85I[/video]
PWM
Can you post a picture of the damaged board?
LSuveg1
Yep -- I need to post again before I can upload them, but will get to that quickly...
LSuveg1






I'm attempting to show the burned solder pad/possibly bad connection near "C101" on the PCB in that last picture.

And I should note: I originally had a short (the crossfader pot sparked when I turned it), which is why I removed the original pot, and damaged the original polyester caps (which have since been removed). Rampage channel "B" seemingly works normally. I'm wondering if the sparks damaged any of the ICs near/beneath the pots, but am not sure how to check them.

Thanks!
PWM
Is the pad that's right above the C101 printing still making contact with the part it should make contact with?
LSuveg1
I'm not sure that it is; I think the pad got damaged during my initial removal attempt, because it was really difficult to solder the lug back into position after I replaced the pot. I can't tell where the lug (at the pad above C101) attaches. I suppose I could solder a jumper from the lug to its intended point of connection, but... I'm not sure where that is (i.e., still trying to learn how to read schematics, and I must be overlooking it when I checked both sides of the PCB). The other lug on the pot has a really obvious trace leading to it, but I can't tell with the one above "C101."
GryphonP3
Befaco does warn that their dual gang pots are pretty specific. The sliders look a little more standard to me, but still, if you get sliders with pin placement a few MM off, you're out of luck, and mouser sliders aint cheap. I build enough befaco modules that I usually spend $50 every now and then on their pots, sliders, and switches direct from them, and they last me for a good 5-7 modules. Their switches are quite high quality too and compatible with a good amount of pcb-mount footprints, so it doesn't hurt to have extras on hand. All the other parts are standard. Use 1/4W resistors stacked vwrtically on the opposite side of the silkscreen and the pcbs will still sandwich easily. I've done this for 5 rampages.
PWM
C101 seems to be connected as should becouse it is part of the second slope generator's range switch circuitry, not the first.

You said the LED lights up sporadically, this is in a random manor?
I think the best way to proceed is to track the signal with a scope. This way you can see where it stops.
LSuveg1
As far as the sporadic nature, I realized it's actually ONLY upon power up of the system; if I turn a knob or move a slider, the LED stops and won't activate again.

And thanks, PWM -- i appreciate the guidance -- Befaco's support advised that I check the Eagle file and follow the circuit, and since I have one working channel I can compare the two. So... off to go educate myself on schematics and Eagle, I suppose!
Southfork
LSuveg1 wrote:
As far as the sporadic nature, I realized it's actually ONLY upon power up of the system; if I turn a knob or move a slider, the LED stops and won't activate again.

And thanks, PWM -- i appreciate the guidance -- Befaco's support advised that I check the Eagle file and follow the circuit, and since I have one working channel I can compare the two. So... off to go educate myself on schematics and Eagle, I suppose!


I pretty. I have have the same problem with channel A. Cycles fine until I move the shape knob or sliders then it goes dead. Channel 2 is fine. Not got all the time in the world for diy at the moment so let me know how you get on thumbs up
smithknows
Modular Addict.com has Befaco components.
LSuveg1
Southfork wrote:
LSuveg1 wrote:
As far as the sporadic nature, I realized it's actually ONLY upon power up of the system; if I turn a knob or move a slider, the LED stops and won't activate again.

And thanks, PWM -- i appreciate the guidance -- Befaco's support advised that I check the Eagle file and follow the circuit, and since I have one working channel I can compare the two. So... off to go educate myself on schematics and Eagle, I suppose!


I pretty. I have have the same problem with channel A. Cycles fine until I move the shape knob or sliders then it goes dead. Channel 2 is fine. Not got all the time in the world for diy at the moment so let me know how you get on thumbs up


Shelving the project for a bit, but will definitely update if i figure something out!
tassie tiger
Hiya,

Just preparing my order listing from the Befaco BOM.
Does anyone know whether the solder pins of generic toggle switches fit through the Befaco PCB, or do I definitely need Befaco/Mouser ones with thin solder pins?

Tayda https://www.taydaelectronics.com/electromechanical/switches-key-pad/to ggle-switch/mini-toggle-switch-spdt-on-on.html
versus
Mouser http://au.mouser.com/ProductDetail/Carling-Technologies/2M1-SP1-T1-B1- M2QE/?qs=%2fha2pyFadugPXJRZa%2fcy4ExkGBhcv9%2fjPdQUTLWvJ8Vm9IIGUwwAl7R BBNTVKjPr

Thanks for any advice
rithma
Looks to me like the tayda ones have the solder-lug looking rings, which will not fit your rampage panel unfortunately.
If at all possible, you might have a look around some other (local?) shops before spending Mouser money... I get mine at a shop here in LA for a buck or two:
http://www.allelectronics.com/item/mts-5pc/spdt-on-off-on-mini-toggle- switch-pc-terminals/1.html

AllElectronics does do mail order but not sure if they ship all the way down there.

/E
tassie tiger
Thanks for yr input

Quote:
..have a look around some other (local?) shops before spending Mouser money..


Big cities like LA have lots of people hence lots of choice. I choose to live on small island with hardly any people, and therefore have to accept that choice is much more limited or, if it is available, costs silly money.

Thanks for the link to Allelectronics - as you suspected they only ship within North America.

I'll keep on searching for on-line stores like Tayda that have choice and can deliver to the bottom of the world for reasonable charges.


thumbs up
parliament_119
Hello!

I'm having some problems with my DIY Rampage :(

I can turn it on and the Balance Output, Min, Max & B>A Output seem to respond and work.


The Problem is that once i trigger A or B they each stay at Rise and seem to be stuck at it. The Out-LEDS do not show anything, the Sliders seem to have no Effect and i think i'm getting a constant Voltage out from A and B, but definitely not the way it's supposed to work. (Same for Cycle Mode)


I did the mistake of soldering the Transistor T103 on the Control Board the wrong way around the first time. Could it have damaged anything?
Also I'm not sure about the Polarity of the electrolytic capacitor C29 on the Main Board?

MAIN BOARD Front
https://picload.org/view/dggoadlw/img_20170907_154342_hdr.jpg.html

MAIN BOARD Back
https://picload.org/view/dggoadcr/img_20170907_142429_hdr.jpg.html

CONTROL BOARD Front
https://picload.org/view/dggoadcl/img_20170907_142523_hdr.jpg.html

CONTROL BOARD Back
https://picload.org/view/dggoadca/img_20170907_142507_hdr.jpg.html


I hope anyone can help me smile

Thank you!

EDIT:
So i'm trying to narrow the problem down. When i put something in IN A or IN B they slew my input or filter it. I can also control the Rise and Fall and its CV on both sides. The Exp. CV also works but seems to be inverted: the rise and fall time get longer when i apply negative CV and vice versa. (Or is it supposed to be like that?)
The only thing that does not work is when the rampage is supposed to generate Envelopes on its own. As soon as i trigger it or put it in cycle mode an trigger it, it gets stuck. The Rise LED is bright and thats it. The Out LEDs do not light up.

EDIT 2:
I wanted to check if the two OUT LEDs have the right polarity with a multimeter. They both did not lit up either way. So i assume they are both broken or their is a problem in the circuit which would be blocking the current??? (I don't have any real electronics knowledge, just an idea)
revel8or
Parliament, so, I looked at you photos, and there are a couple of concerns.

Please bear in mind that I am not being personal, I just want to offer some suggestions on your build, and I think I see a problem or two.

I don’t have your unit in front of me, so I can’t power it up with the Toaster and run the oscilloscope and grab the multimeter, so I’m really eyeballing it, here.

The pattern of the solder in the back of the board, as well as how it looks in several spaces on the front leads to a conclusion that the soldering iron isn’t heating the component and the trace simultaneously. The solder is balled up on the back side, and it doesn’t come all the way through the hole on the component side. This build required me to break out the itty-bitty tip, as the pads are *so* small that getting it hot as the component wire heated was a bit of a trick.

As the pad and component are heated with the iron, place the solder on the opposite side of the iron. Allow the temp of the component and trace melt the solder. When the junction is hot enough, the flux will flow in to the hole (assuming that rosin core solder is used) and the solder will follow it through to the component side.

When using this method, I use the “discomfort alarm” built in me brain - if it seems like it is taking too long to melt the solder, it is. I clean the tip immediately and re-tin it. This is a very important step to assure that heat is not being insulated by a layer of oxidation that happens to the soldering iron by just being heated up.

The next thing is trimming the components. There are a lot of places where the leads are pretty high. They should be as close to the board as possible, especially with this build as things are sandwiched together.

There appears to be one component lead touching “Fall A CV” slider. This will not account for every issue, however.

Look in to getting a soldering iron with a tiny tip. I use the Solrep 2000 - 18 bucks on Amaz0n, and I change the tips with some degree of regularity. Also, look for some *tiny* snippers to get the leads clipped as close to the board as possible. When working with stuff this small, trimmers used to trim romex don’t offer the degree of precision needed.

Also, this is a sandwich build. Great for space, bad for faults. If there are components shorting when everything is put together...so it is super important to lay everything flat as possible on the PCB.

The points where the solder is balled up - you might be able to reflow by adding some flux. Also, there seemed to be a burned pad? Not sure - it could be darkened flux...

Not trying to be mean, just trying to help.

parliament_119
Hey Revelo80r,

Thanks for taking your time.

I can't test your instruction, because i sent my Rampage to Befaco for the Happy Ending Kit. Unfortunately my parcel got lost.

I did built another one in one of the workshops and it worked there. Once i got home i had the exact same problem as with the one before.
Turns out i used to less Voltage on my Power Supply.

So my first Unit was propably ok.

Noob Mistake i guess grin

Regards
revel8or
I’m glad that it worked out well for you. I’m sorry that your package was lost. I tend to think of board population (as with any DIY, for that matter) as an investment in time and energy, which IMHO, worth more than what I would be spending on a completed unit.

I *still* haven’t gotten mine up and running - again, time...although what I’m working on might be of interest to the modular community... smile

We’ll see...

- rev

And I can’t help but think of Parliment, now. Time to break out some LPs hihi
mikeholzheu
Hi,

i built a befaco rampage last week.
Everything works fine but the rise slider on the right side has no effect
- doesnt work. i controlled all solder points near the region of the slider and soldered them again...no effect.
Does anyone have an idea?

thanks a lot

best regards Mike
revel8or
Howdy, Mike

I'm looking at the schematic, so slap me if I get the component numbers incorrect.

Can you test the slider in place using a multimeter, just to make sure that it's OK?

After that, check connections and ground points for:

R113
R33
IC3B - ground point
R33
R35
R41

and is D11 reversed?

https://www.befaco.org/img/Modulos/Rampage/Rampage_1_3.pdf

Symmetry B works, right?

Oh, and if I remember correctly, there isn't a lot of space between the bottom of the sliders and the solder points underneath them. I used a piece of electrical tape as a shield between the two...that's a long shot, but worth looking at.

Edit: it wasn't the Rampage that I used the tape with. Sorry! I had a momentary brain issue - it was the Turing Machine MY ASS IS BLEEDING
mikeholzheu
Hi,

the sliders are both ok.
i changed every resistor you named.
D11 is in the right direction.
i m only a loosy diy beginner.
where can i found the icb3 ground point
and how to measure a groundpoint?

thanks a lot and best regards Mike
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