common problem?

jonathansuhr · May 01, 2009, 02:19:07 AM

I built a L***P**** Et*****y clone and the gain pot does nothing. full cw or ccw, it seems to be at full gain. the tone control isn't doing anything either. Is it most likely a solder bridge or something? faulty pots?

petemoore · May 01, 2009, 10:50:48 AM

Here's the ''quick-cure'' method, we need this information to find a fix:
http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

jonathansuhr · May 01, 2009, 01:37:29 PM

I was just asking, because I'm not sure if I'm allowed to post schematics and layouts for this pedal..

petemoore · May 02, 2009, 01:52:31 AM

I think you can mention or PM me the name of it.
If it's really one of those pedals, perhaps you can ask the dude who makes would be interested to assist in the project.

aron · May 02, 2009, 02:01:22 AM

Well, the obvious answer is that the pot is probably mis-wired. If it's like a tubescreamer - you only need to use the middle and outer lug. Try this first and see how it works.

Projectile · May 02, 2009, 03:50:07 AM

To clear up some confusion, the L***P**** Et*****y he's talking about is basically a modified Tubescreamer.

It is highly unlikely that the pots are faulty. You probably mis-wired something. What layout did you use?

MohiZ · May 02, 2009, 04:13:35 AM

If they are very bad pots, they can easily fail from the soldering. I've had that happen many times, though never with better pots such as Alphas. It's still more probable it's a miswiring or a bad soldering joint somewhere. Which pots did you use? Check them with a DMM.

Projectile · May 02, 2009, 05:06:34 AM

Quote from: MohiZ on May 02, 2009, 04:13:35 AM
Check them with a DMM.

^^ Best idea.

petemoore · May 02, 2009, 09:58:33 AM

clone and the gain pot does nothing. full cw or ccw, it seems to be at full gain. the tone control isn't doing anything either.
Perhaps it is something common to both pots, such as bias in the circuit.
First thing I'd to is check voltage between pins 4 and 8, then every other pin from ground, to see what the bias is like in there.
Is it most likely a solder bridge or something?
Yes, the above statement It is absolutely guaranteed.
faulty pots?
You can check them, but 2 bad at the same time...pretty doubtful, there's something else common to both, causeing them to 'malfunction' {At least that's my theory...the pots are probably just fine.
The Debugging Sticky thread...even pedals with special mojo or other unrevealables may find it hard to continue malfunctioning after a few good debug tries.

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common problem?