SHO Debug

[Dulouz]

Hi Guys!

So I finished wiring up my SHO (compact) build and I've got nothing. I get sound when it's "off", but once I engage the effect I have no sound. No LED light either.

As far as I can tell I don't have any cold joints, but I could be wrong. I've checked out the layout and it looks good to me. Here are a few photos that I hope will help.







Any ideas on what I've done wrong would be greatly appreciated!

[GoranP]

OK, just to get things rolling here...

I don't seem to see any knife marks and that lower left corner of the first picture seems fishy (either a solder bridge or a picture artifact so I gotta ask... did you knife your gaps? Also, on the first picture the "upper" leg of the 100n seems like it could use some reflowing, hard to see because it's out of focus.

Second, not that there's anything wrong with your way but you can save yourself the hassle of wiring two little wires for the ground on the footswitch (second picture, top right corner) by taking a resistor lead, bending it 90 degrees and threading it through the lugs.

On the third picture, again, nothing wrong with it but you can wire the gain pot with only two wires instead of three. Just strip off a bit more for the "gain 1&2" at the pot side and use it to bridge lugs 1 and 2.
EDIT: see here. Not the most stellar soldering job but you can see what I'm saying


On the fourth picture, I have three comments. Firstly, it appears that you didn't socket your transistor. That could be your problem right there, thermal damage to it due to soldering. Try replacing the transistor but first solder in a socket for it. Secondly, it is early morning here and I didn't have my coffee yet but I can't really figure out what do you need three jacks for? Input, output and....?
Thirdly, I really cannot see what's going on with your dc jack. Perhaps it's shorted or a cold joint? Also, it's kinda hard to see but it kinda looks like your led polarity is wrong? The cathode should be on the footswitch side and to me it seems like it's on the resistor side?

Also, consider building an audioprobe. Helps immensly when you are just starting out and you aren't yet versed in audiovisual troubleshooting. I've posted details yesterday in one of the threads.

[Madferret]

Can I ask if you tested the board before wiring up the footswitch and LED? I learnt early on that it helps to have a little 'test rig' breadboard to test my builds before I start the off board wiring.  This helps you identify where the problem lies, there's no point going through the long process of fault finding on the board if the problem is the switch or the soldering on one of the sockets. I just wired up a couple of 1/4" mono sockets and a DC socket and pluged them into a small breadboard I've got, then I can just drop in whatever circuit I've just built and check that it fires up, it doesn't have to be via a breadboard, you could just attach crocodile clips to the sockets instead.

So my advice would be check that the board fires up without the switch and LED etc, if it does you know the problem is with the wiring or possibly a faulty stomp switch.  If the board still doesn't fire up, I'd take Goran's suggestion of reflowing the solder at any dodgy spots then use a sharp knife to cut between the tracks. If it still doesn't work I'd probably switch out the mosfet and check the orientation of the diode and the electrolytic caps.  After that all that's left is to check that all the components are in the right places, but I'm kind of assuming you've already done that.  Good luck!

[Dulouz]

Thanks for all the help and suggestions guys!

I knifed in between the strips, reflowed one of the joints and switched the DC jack wiring. Now I have a working SHO clone that sounds amazing!

It's not pretty, but it works.

[GoranP]

Glad you got it straightened out!

Can't help wondering, yet again... what's the third jack for?

And also... your enclosure seems like it is partly painted on the inside but you may still look into isolating the board and the components from the enclosure, putting it right next to bare metal is just asking for grounding and shorting issues.

[JaviCAP]

Goran: The original SHO has a double jack output, so you can connect the pedal to two different devices.

BR

[GoranP]

Thanks Javi, I didn't know that... it's just wired in parallel like that?

[JaviCAP]

Yes, two outputs in parallel, no big secret :P (and not sure if big use :P)

[Dulouz]

That's right. The original SHO has two parallel outputs. I don't know how often I'll use it, but I had the extra jack and wanted to keep it somewhat true to the original.

Thanks again for all the help!