Hello /diy/. I need help troubleshooting this guitar pedal.

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Insides I

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Insides II

Does it get power? As in, are the components on the PCB really powered?
If yes, check your soldering next. In desperation you might want to add some flux and re-heat all the joints.

>>1021704
Yeah, it gets power (I guess, since the LED turns on when I activate the effect)

How can I check what you're telling me?

Did you use a power supply with the wrong polarity at some point?

>>1021725
No I haven't. The pedal had been in a friend's house, and I retrieved it some time later but not working. But he claims he hasn't ever used it.

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>>1021706
Visually and by wiggling components (joints shouldn't move).

>>1021730
Wouldn't be a surprise if he burned it by using a wrong power supply.

>>1021737
The thing is that this pedal has always worked fine; but somehow it does not function no more. Shall I check the soldier joints even by knowing this? Does soldering iron "get spoiled"?

I wiggled the components and looks like they are stable.

What if he used a wrong adaptor? does this have a solution or may I have my PCB bassicaly burned down?

>>1021737
>Wouldn't be a surprise if he burned it by using a wrong power supply.
this. There isn't anything on the board that is likely to go out without being visible besides the ICs. Blown caps and resistors will be obvious by visual inspection. If all the solder joints check out, I would suspect the two ICs, which are most likely op amps. You can try replacing them if you trust yourself with a soldering iron. Try asking the people you bought the pedal from.

>>1021739
It is perfectly possible to make bad joints which work initially, but stop working when they eventually oxidize or when you drop the pedal or whatever.

It's bit difficult (tedious) to say what wrong polarity or overvoltage does to your pedal, but since there are no visible burn marks, the worst case is that all the semiconductors and electrolytic capacitors are shot. Damage to that extent is unlikely, though.

>>1021730
Grill your friend. It's likely that he busted it.

>>1021750
This seems likely to me. If it was fall damage, it will be hard to repair on your own.

If it's oxidization, try Deoxit:
http://store.caig.com/s.nl/it.A/id.2946/.f

If you own any musical instruments or sound reinforcement gear, it will come in handy.

Did you check continuity across the switch? Itself? If the switch wore out it might not be making a connection inside to the pole that directs the signal to the board.

>>1021942
Yeah I made continuity tests in the switch but as I said, I'm not electronics expert. The True Bypass wiring functions properly; but how should I check that the effect-in and effect-out are working properly?

I posted pictures in >>1021698 and >>1021701

OP, you fucking stoner! You had the input (guitar) and output (to amp) mixed up. That's why it worked in bypass mode. Put it back together and try again.

>>1022530
Whaaat? I'm pretty sure I'm plugging it correctly, lol

OP Here. Update: I made continuity tests across the integrated circuits (it has a classic LM741CN opamp and a RC4558P). They have no continuity whatsoever. How should I check that they are working properly?

And thank you all very much for your kind advices!

>>1022567

these continuity checks can only get you so far. your next course of action is to check the voltages across the op-amps. the 741 has power across pins 4 and 7, with 7 being positive. so measure between those 2 pins. repeat for the 4558. pin 8 is plus, 4 is minus. how do you know which is pin 8? google it. look for the notch.

if you have power on both chips, next you gotta trace the path of the signal. use an audio amp, like a powered computer speaker, and probe the path from input thru to the output of each op-amp: on the 4558 that's pins 1 and 7, on the 741 it's pin 6.

>>1021942
>continuity across the switch

Also check the pots. Make sure there is a fixed resistance between the two outside terminals and that the center terminal to one side or the other varies smoothly. Sometimes these things can get oxidized and loose contact internally.

OP UPDATE: Sorry for not posting here so often. I have made continuity tests across the ICs and there isn't continuity between Vcc and Vee; what's more, there isn't any kind of continuity. Sometimes the multimeter makes a little continuity whistle but less than a second. So I'm guessing that the ICs are fried and I think i'm going to replace them on a desperate move and see what happens. What do you think?

Shameless self bump, just in case