MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

Broken Seismic Industries VC ADSR - Help
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Broken Seismic Industries VC ADSR - Help
nmason10
So I've been a wally and put the power cable on this module the wrong way round, after having a rack shuffle.

When plugged the wrong way round the module's gate LED comes on but no function. When plugged the correct way, no function at all.

It's all SMD components, so I messaged the company about repairs, but he's charging around £60 an hour plus shipping to and from Switzerland. I bought the module second hand for £35, so this makes no sense for me.

Just wondering if anyone here could guide me in what may need repairing, or would be willing to take on the job for a more cost-effective price for me.

Or of course, it could just go in the bin...


Cheers
nmason10
Forgot to say, I'm in Nottingham, UK.
das_Produkt
Can you tell us the type of ICs that are used on your module?

Most of the time these are the first components that die.
seismic
sry - i unfortunately can't work for free...

it's:
3x tl074 TSSOP-14
1x cd4052 SO-16
1x lmc555 SO-8

good luck
djs
pictures of both sides of the circuit board?
acgenerator
FUUUCCKKKK!!! FUUUCCKKKK!!! FUUUCCKKKK!!! FUUUCCKKKK!!!
a "i flipped the cable" break normally results in one of a handful of cases:

Case 1: the module had reverse power protection and it's a fried fuse, low value resistor or diode. Generally this part would be placed immediately after the power header. You can check for burn marks/ destroyed components.

Case 2: module is NOT reverse power protected. More often than not it'll be c chip that goes out as most have expected voltages at certain input and you send very wrong voltages down the circuit. Look for a crack on the chip casing or burn marks underneath. Digital chips are the most sensitive to this.

In your case I'd check the TL074s first (op amps) first. Too bad they are tssop rather than a socketed chip cause you could have used known good chips from another module to test.

The good news is the op amps, the 555 (timing clock), cd4052 (4000 series switch) are all common / cheap parts. The bad news is surface mount is a pain to desolder.

Case 3: you'd have to test the whole circuit. even if it was clear which area was damaged, you'd have to have a really good understanding of the signal flow to know what to fix.

Based on your initial post, it sounds like you'd be comfortable enough with a Case 1 or maybe Case 2 fix if someone could point you in the right direction.

if it's case 3...For this module, I'd offer it as a "for parts" get a little bit for it and let someone with serious skill / interest or at least a working version waste their time on it. If it was something else it may be worth more time investment. Not sure you'd get any takers because the value may not justify the time and effort for someone capable of fixing it.


if you post some pics we *might* be able to help determine which case it is. A picture of both side of the boards and close ups on the chips and the vicinity of the the power header on the component side would be the best shots to take. If it's not marked on the board. let us know which side of the header is which is -12v.
nmason10
Believe me, I expect nobody to work for free and for nobody to undercut their Labour, being a trade unionist and all.

I just can't justify nearly twice the amount I paid for the module to get it shipped to you and repaired, especially just after Christmas when I'm very down on funds, so looking for advice to do it myself or for someone closer to home.

seismic wrote:
sry - i unfortunately can't work for free...

it's:
3x tl074 TSSOP-14
1x cd4052 SO-16
1x lmc555 SO-8

good luck
nmason10
I've attached some pictures, but my phone's camera is not the clearest close up.

I can't identify any clearly blown components from sight, although being SMD, which I'm admittedly less familiar with, it is harder to see








acgenerator
you will need much clearer photos for anyone to assist remotely.
fuzzbass
Are you kitted up to work with SMD? You need specialized heating tools and materials. If you attempt to remove a chip using a soldering iron, you will very likely fail and lift pads from the board.

If you are not equipped, my advice is to let this one go and get another ADSR. If this was something special or rare like a Rungler or complex oscillator, I might counsel otherwise. But it's just an ADSR.
nmason10
Yes I'm now of that impression, just hate to see things chucked away.

I was more interested in seeing if anyone would be willing to take the job on more cost effectively than having to ship it to Switzerland and back...

fuzzbass wrote:
Are you kitted up to work with SMD? You need specialized heating tools and materials. If you attempt to remove a chip using a soldering iron, you will very likely fail and lift pads from the board.

If you are not equipped, my advice is to let this one go and get another ADSR. If this was something special or rare like a Rungler or complex oscillator, I might counsel otherwise. But it's just an ADSR.
seismic
a cheez

i hate things getting thrown away as well. seriously, i just don't get it

not that using that kinda logistics between UK and switzerland would be to economic either but at least i won't be trashed right away.

so, i'll repair your board for free if nobody near you is gonna do it.
you just need to cover the postage costs. (like 15 or 20 CHF tracked to UK)

best
r
Jarno
It seems to have something between the connector and those electrolytics, are they ferrites or power diodes? (the two grayish blocks).

In general though, I think boxed headers solve at least part of the issue. In a commercial design, I would expect some mitigation for the risk of plugging in a power connector backwards. If it is buried in the innards of a piece of equipment, only to be touched by capable personnel, you can expect them to RTFM (although as I experienced recently, quite often they do not either). But in a modular synth, the power connector is handled by the user, so some robustness is needed or you'll end up with returns.

Nice website btw, I really like that flat skiff, and the idea to make all signals available on pinheaders underneath the panel (although if you have too much going on, it could turn out to be a bit of a head scratcher smile ).
seismic
Jarno wrote:
It seems to have something between the connector and those electrolytics, are they ferrites or power diodes? (the two grayish blocks).


neither. its inductors, they form an LC filter at the input of the board.

the design only allows you to plug in the connector on the module in one way. if you try it bottoms-up there will be the connectors nozzle in the way of the pcb.

and on the other end of the cable there can be any kind of busboard..

it can happen to the best of us imho.
nmason10
If you would be prepared to do that, that would be amazing...

Let's give it a couple of days to see if anyone close by is prepared to take the job on first? I really don't want to put you out...

Cheers

seismic wrote:
a cheez

i hate things getting thrown away as well. seriously, i just don't get it

not that using that kinda logistics between UK and switzerland would be to economic either but at least i won't be trashed right away.

so, i'll repair your board for free if nobody near you is gonna do it.
you just need to cover the postage costs. (like 15 or 20 CHF tracked to UK)

best
r
MUFF WIGGLER Forum Index -> Music Tech DIY  
Page 1 of 1
Powered by phpBB © phpBB Group