General Tso Troubleshooting

[pastachilli]

Hi all,

I am new to the world of DIY electronics and I thought I would try to throw together a pedal from this website. I bought all the parts from digikey and whatnot and soldered it all together, but I am running into issues. First, this green light stays on permanently which I don't think is correct based on other videos people have posted. Second, I am getting unbearable amounts of noise coming out of the pedal, and I am not sure what to do. Here are some pictures of my soldering, and the light staying on when the pedal turns on and off. Also the pots and switch don't seem to have any effect on the noise or sound coming out of the pedal.

here is a video of the light staying on:

New video · Saturday, Jun 7 🎬

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photos.app.goo.gl

 

[z2amiller]

I don't see a slam dunk problem, but:

• See if you can clean up the backside of the board with an old toothbrush and some isopropyl alcohol. There's a lot of flux residue on there which makes it hard to see the actual soldering work in your second picture.
• Some of the soldering of the wires onto the board looks dodgy, like you might have some solder bridges/shorts. (Specifically in picture number 3 it looks like out/sw might be bridged)
• Check your transistor orientation if you made any substitutes - BC54XX have a reverse pinout from most 2NXXXX transistors.
• Insulate the backs of your potentiometers. They sell potentiometer condoms, or you can just line the back with several layers of electrical tape (but electrical tape isn't that great since the sharp leads of components can pierce it)

The 'LED always on' and 'knobs do nothing' symptoms point to there almost certainly being a short somewhere, so checking for bridges and insulating the potentiometer that touches the back of the board are the places I'd start. You can also put a multimeter in continuity testing (BEEEEEP) mode and try to find places where there is continuity between things that shouldn't have continuity.

 

[pastachilli]

I accidentally used the wrong transistors, changed them and it seems to be working better now!! Those darn things look exactly the same.

I looked back at the schematic and saw that the only thing between the always on LED and ground was that transistor which helped me discover my problem

It is still super noisy, however I'm guessing that's either due to 1: the fact that its not in an enclosure and 2: the photoresistors aren't in a super dark environment. I'll get the enclosures in the mail soon and hopefully that will fix my problems.

 

[sunking73]

hi, i am also really strugglng with this one. It's my 2nd attempt and it is still not working. I am not an experienced builder at all but i have already built a dozen of Fuzz/OD with success.
I have +9v at the input of my board, but the green leds are not lit. The Red led is ok. When i try to probe i go IN - C1 - R4 ok but nothing in R6 is this normal ?
I measured DC at the opamp.
Pin1 1.26 / Pin2 2.40 / Pin3 3.85 / Pin 4 to 7 = 0 / Pin8 1.26

 

[sunking73]

another question, if i want to test the board without the switch, is it ok to leave MUTE unconnected, Connect SW to OUT and BUFFER to GND ?

 

[Feral Feline]

hi, i am also really strugglng with this one. It's my 2nd attempt and it is still not working. I am not an experienced builder at all but i have already built a dozen of Fuzz/OD with success.
I have +9v at the input of my board, but the green leds are not lit. The Red led is ok. When i try to probe i go IN - C1 - R4 ok but nothing in R6 is this normal ?
I measured DC at the opamp.
Pin1 1.26 / Pin2 2.40 / Pin3 3.85 / Pin 4 to 7 = 0 / Pin8 1.26

You should start your own thread.

You can reference this thread in your own trouble-shooting thread.


Having your own thread helps you, by helping people to help you, ie nobody gets confused with which pedal is being referred to — for example when I saw this:

another question, if i want to test the board without the switch, is it ok to leave MUTE unconnected, Connect SW to OUT and BUFFER to GND ?

... I quickly checked the OP to see what the original problem was and then noticed the OP is not you, and that the OP resolved OP-pedal's main problem.

People are more likely to see your fresh new thread, as well, and not skip over it if they've seen or read this thread already.






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@pastachilli — note when cleaning a board with isopropyl (or any cleanser), don't let any of the solvent or flux residue contaminate the pots!

 

[comradehoser]

Mark as solved?