Tommy III no sound but light works any advice helps.

[yerblues]

Hello everyone! I'm in the process of building three Tommy III pedals but so far the first two haven't worked. the light lights up but there is no sound coming through when effect is engaged, true bypass works as intended and passes a signal though. I checked resistor values as I was installing them, and during my troubleshooting I reflowed all solder joints, I checked grounds and continuity between points and everything seemed to look good, and I also checked that the diodes are all working. Could it be possible I got a bad batch of electrolytic capacitors? I got all my components from Tayda.
Here are some photos. the Installed op amp isn't the one recommended in the sheet, it's a mod but I tried the recommended value as well and had the same no sound results. Sorry about the solder side pics, they came out blurry but I did reflow and check them. Hopefully someone can see something I missed.

 

[AceHyzer]

Hey! I’m not seeing anything immediately obvious but there are maybe a few places that are suspect, it’s just hard to tell with the pictures. I can’t tell for sure, but it looks like there may be some places where there are joints with very little solder? You don’t want a ton but you want enough for a solid joint.

If that isn’t an issue and it’s just the pics, you might look at using an audio probe to trace the audio path of the circuit. That way you can trace the signal through the path it should be following to find out where it’s not making it through. This is probably the best way to track down the culprit.

 

[CheapSuitG]

Is the red wire touching the in joint?

 

[Erik S]

Check R5 and R8

Color bands are tricky in photos sometimes, but it kinda looks like you've got a 1.8k in R5 and 8.2R in R8.

 

[yerblues]

Check R5 and R8

Color bands are tricky in photos sometimes, but it kinda looks like you've got a 1.8k in R5 and 8.2R in R8.

View attachment 94045

Thanks so much! R8 might be the culprit! I'll post an update when I fix it.

 

[yerblues]

Check R5 and R8

Color bands are tricky in photos sometimes, but it kinda looks like you've got a 1.8k in R5 and 8.2R in R8.

View attachment 94045

Thanks Erik! the wrong value at R8 was it. I changed it to the correct value and they both work now. Thanks so much for your help I really appreciate it!

also do you know if it's normal that the pedals from Pedal PCB have somewhat of a pop when engaged? So far all of the ones I've made from Pedal PCB have a small pop when engaged.

 

[Erik S]

Thanks Erik! the wrong value at R8 was it. I changed it to the correct value and they both work now. Thanks so much for your help I really appreciate it!

also do you know if it's normal that the pedals from Pedal PCB have somewhat of a pop when engaged? So far all of the ones I've made from Pedal PCB have a small pop when engaged.

Nice! I’m glad you got it going.

Do some searching in the forum for pop or switch pop and you’ll get some results including some attempted remedies.

I don’t really understand why it happens, but I was very concerned with pop on some early builds, then found that it went away after using the pedal for a while.

If your Tommy is good to go, mark this one solved so anyone reading through from the beginning isn’t looking for the solution.