Muff's Modules & More

[Tim Stinchcombe]

Well I agonized over several of the details as to how to do the mod for a couple of reasons: the original method requires the removal of two surface mount (0805-sized) resistors, and for those that have never done this before (I'm guessing this is likely a fairly high percentage of those that will want to do this...!?), there is a significant risk in damaging the board/pads/traces in doing so; secondly, whilst there is an easier way to achieve the same effect, this was going to make Sandy's modules behave ever-so-slightly differently (which if they were mine, would have bugged the hell out of me!). Thankfully the tactic of not rushing into things, and mulling everything over for a few evenings revealed there was a staring-me-in-the-face obvious solution to the 'compatability' problem between the two methods, so here is my slightly (I think) easier way of doing the mod. It requires two fewer resistors and not removing anything, though there is still (unavoidably) some tricky soldering required to hook directly-up to SMT components.

Bits needed are:
- an ultra-miniature two-pole changeover switch. I used the code FH99H one of these - click the 'specification' tab for the size
- a 10k and 24k resistor (though a 27k would do equally as well rather than 24)
- thin hook-up wire (I used Kynar, as used already for the factory-fitted mod)

Here is the circuit detail of the mod itself - the switch and everything to the left of it is new, the rest is existing:



First thing to do is remove the wire running between the 'aux out' socket and the 'ext rate' socket (damn - forgot to get a picture of this!). Also cut the track running between the 555 and the TL074 chips:


Then drill the hole for the switch - I drilled slightly down from center, so as to match Sandy's other modified module, and also so that the switch won't obscure the writing:


An unfortunate downside of this is that it leaves less space for the switch between the sockets, which have to be angled out to make the space. I cut and removed the ground wire running through the tabs on the sockets, the bottom pair can then be rotated to make enough space for the switch, then re-thread some new wire and re-soldered everything (note the last snap in this sequence is taken from the top!):


Solder a 24k resistor between the ground wire and the left-lower tab on the switch:


The 10k resistor goes between the right-lower switch tab and the 'ext rate' socket - I bent the unused 'switching contact' tab out of the way, and with careful bending of the resistor legs I reckon the whole lot is sufficiently placed (and rigid) so as not to cause any possible shorting hazards, but use insulating sleeving as you think fit:


Then cut and strip three suitable lengths of wire, and tag one each in turn, to: the two 100k resistors making the potential divider:


...the 1k resistor just above the 555 chip:


...and pin 9 of the TL074 chip (if you don't have an empty socket in the 'EXP' 16-pin DIL footprint in the middle of the board, this one can go to pin 10 there, if you like - beep it out with a continuity tester and you'll see it is the same place!):


Then attach the other ends of the wires to the switch, as shown:


That's it! Here is snap of the whole, though I have yet to add a gob of goop to tag the wires in place:


When the switch is down, it runs off the internal clock; when up, the clock supplied through the 'ext rate' socket drives it.

With the 24k resistor, the level at which the external signal clocks the module is approx 2.4V, which is close to that of the original modification; if you were to use a 27k instead, it creeps up a little to about 2.6V (i.e. not a big deal).

Hopefully I haven't forgotten anything, though perhaps it goes without saying you need a soldering iron with a very fine tip (mine is 0.4mm I think, and the shaft is narrow enough to manoeuvre between everything), and also a steady hand!

If you want higher res (though unannotated) photos, PM me; I also made up a gif of the original mod, so if anyone wants to see the difference I can post it...

Tim

[Edit record:
edit 1: the 'EXP' header is 16-pin, not 20! Don't know what happened to my counting there!]

[sandyb]

thank you so much Tim

i hope this will be useful for all the other frac noisering owners who want to modify their modules.

[rezzn8r]

You are awsome, Tim. Thank-you very much for your time and brainpower.

[solitaryzen]

Thanks so much Tim - fellow member Cleaninglady is going to perform this mod for me

I notice the mod was done on the 8 jack version - mine is the 6 jack version, but hopefully the above notes will still apply....?

[otoskope]

Wow! Thanks heaps. Will try to do this to my three bananafied noiserings. Shouldn't be too man changes because of the bananas, I guess?

/palle

[Tim Stinchcombe]

[Tim Stinchcombe]

[solitaryzen]

[jenamu6]

Thanks Tim.....Now I have to find the guts to actually perform this mod.

[Tim Stinchcombe]

[sandyb]

i'm going to sticky this thread for the benefit of any future wigglers who wish to perform the mod.

thanks once again to Tim for his time and skill

i'm looking forward to my noiserings returning!

[marketingslime]

Awesome Tim! Thanks so much...very helpful.

[marketingslime]

[quote="Tim Stinchcombe"]

[Tim Stinchcombe]

[cleaninglady]

I just finished this mod for solitaryzen.
Much more nerve racking doing it on someone else's module i must say...

Didn't have any solder smaller than 0.7 and my Soldering Iron tip is 1.4mm but i managed.

You need a really steady hand.

I ended up using the 10th pin of the Empty Socket at 'EXP' as i was a little wary of soldering the TL074 pin 9 with such a large Solder tip. (Thanks Tim for the advice).

Just soldered the wire straight to the socket conductor.

I used a hole punch to get the drill starting point for the hole in the panel and drilled it with 3mm then a 5mm bit.

Be very careful when soldering wires to the SMD components and gentle when soldering the switch. They are delicate and you can easily kill the switch by melting the housing around the conductors causing them to shift and the switch to malfunction or just not work at all.

I don't really recommend the size of solder tip i used but i'm just showing it has been done with regular gear.

Be brave and give it a go.

[solitaryzen]

Looking forward to getting it back and finally being able to sync up the clock

Thanks!!

[jonat8han]

I'm working on this mod right now, but I've been unable to find a switch of the proper size from an US dealer - anyone have a mouser or allied part# for one that's suitable? Everything I've found has been too large ...

thanks!

[jonat8han]

I found a switch at a local electronics place (no part# that I can see on it, sorry) but I've managed to do the mod successfully! Felt a bit of a shame to drill a hole in my nice blue NR panel, but it works & I'm very happy - thanks for all the info in this thread. I feel like looking at the measurements, that this Calrad switch would work, but I wasn't able to get my hands on one - http://www.calradstore.com/40-609.html

[dogoftears]

i am about to score a frac noisering and i'm wondering if a fellow sf bay area wiggler would like to help me perform this mod... i will buy you 2 beers and smoke you out with 3 spliffs. but after.