Son Of a Ben no signal

[BJG]

Hey!
I built a Son of a Ben preamp and it won't pass any sound when engaged.
It passes signal in bypass and Q1-3 are biased to 4-5V each.
Any idea where I should check for bad connections? I feel like if I can bias the transistors, the majority of the circuit is good to go, but I'm an amateur, so who knows.
Thanks in advance for any advice!

 

[Erik S]

What’s going on here?

 

[jwin615]

First, thank you for not off board wiring everything.
Secondly, painters tape ain't gonna cut it.
Lastly, make sure the dual pot isn't contacting the pot above it.

 

[jimilee]

What’s going on here?

View attachment 108819

And all the other solder joints that’s look like that. Go ahead and reflow them all. It will only help.

 

[Erik S]

And all the other solder joints that’s look like that. Go ahead and reflow them all. It will only help.

I was just wondering why there’s no capacitor there.

 

[BJG]

What’s going on here?

View attachment 108819

The schematic called for that part to be omitted

 

[BJG]

First, thank you for not off board wiring everything.
Secondly, painters tape ain't gonna cut it.
Lastly, make sure the dual pot isn't contacting the pot above it.

no contact on the dual pot, but there is tape below it to prevent any contact below; its possible the tape failed

 

[giovanni]

no contact on the dual pot, but there is tape below it to prevent any contact below; its possible the tape failed

Painters tape is not gonna help. Electrical tape is also usually ineffective. Try a small piece of thick cardboard or, if the board is outside the enclosure, try lifting the pot a bit to see if that changes anything.

Some of the solder joints look like they may be cold but it’s a bit hard to tell from the pics. You also have a lot of flux residue, which shouldn’t be the cause of the problem but I suggest cleaning it up (you can use isopropyl alcohol) because in some cases it can create problems especially after a while. At the very least, the flux makes it a bit harder for us to see.

 

[BJG]

[SOLVED]
I put thicker material between the board and the pots and the pedal works now. Must have been some metal poking through the tape and contacting the pot

 

[jwin615]

Tayda/SBP/LMS all sale pot dust covers. They're 5-10 cents and a worthy investment. You only need them on the pots that mount over the board, unless you have a tight build where a jack could short to a pot.

 

[giovanni]

[SOLVED]
I put thicker material between the board and the pots and the pedal works now. Must have been some metal poking through the tape and contacting the pot

Painters or electrical tape has got to be the top cause of troubleshooting threads!

 

[jwin615]

Painters or electrical tape has got to be the top cause of troubleshooting threads!

We should get a group together and make a troubleshooting venn diagram. It would probably solve 60% or threads before they start.