Peavey Bandit 112 Transtube - Dodgy pots?

[black_box]

Hi, I am new here but I was wondering if you could help me, I have a problem with my peavey bandit 112 transtube (produced around 1994)

This first happened halfway through a rehearsal. When playing, the volume suddenly jumps really loud and stays maxed out regardless of where you set the volume. This happens on the clean and dirty channels and independently of each other.

I am guessing it's the pots because (and I'm not a fan of doing this) by twiddling a bit with the knobs (pushing and pulling) you can usually get it back to normal.

So my question is, would this require replacing the pots? They are both square and braced (I'm afraid I don't know the resistances).

Clean Volume labelled (on the PCB) as VR1 Volume
and on the pot as:
I Ø d
A254

and

Dirty Volume labelled VR9 Post Gain;
I Ø d
B254

I'd appreciate any help!

[Chuck H]

It could be the pot. But it's more likely the joint where it meets the circuit board. Specifically the ground pin. You could try to re flow the solder joints on the pins. If that fixes it, your done.

It's probably a standard 16mm pot (I don't know the value either). You can get them anywhere. If you just replace it you can deal with both possibilities at once. Just take it out and measure the resistance between the two outer pins. Then order a pot of that value. If the two outer pins read infinity ohms then it's certainly the pot. In that case, to get the value you would have to measure from one of the outer pins to the center pin. Rotate the pot to find the highest resistance. Round up to the nearest standard value. There may be a part # on it and if you can order by part # then your sure to get the same taper too. Peavey has always been very helpful with me. If you call them they could probably give you info to order the part so you can continue to use the amp until the new part arrives.

Chuck


Chuck

[black_box]

Wow, thanks for the speedy reply.

The main volume is really dodgy, but the dirty channel (post gain) appears to be 7k Ohms. Does this sound like a realistic possibility?

I'll give peavey a ring tonight then. Thanks so much for the advice. I'm thinking that it'll be a new pot because the soldiering looks pretty good as it is.

[Enzo]

Don't care what it looks like, reflow each solder connection.

Othewise, you can order any parts in their products straight from Peavey.

[black_box]

Yeah, resoldering hasn't helped. I gave them a ring at peavey - they were very helpful.

They sent me some schematics of the amp and now I've been able to identify them as 10k pots. I'm gonna have to order through a dealer though, being UK based.

Do you have some database where you store schematics? I remember seeing some pages of various schematics - Enzo? If they'd be useful I can send you the ones for the bandit.

[Enzo]

Just contact custonmer service at Peavey and request the drawings. I can download them and post them, but you can eliminate the middle man.

Have your serial number handy and look on the serial # plate for the exact model name - Like Bandit TT '04 or whatever. There are many updates and revisions for these. SO the year matters.

[black_box]

The folks at peavey were very friendly and helpful. It turns out my model is a fairly non-standard issue. It was from the first chinese-made bandit run and they used non-standard pots and so on.

The chaps at peavey sent me some pots but they turned out to be for the later model and it seems they don't have pots for this model. I might be lucky being able to fit newer ones or not. They're gonna get back to me on this.

[Enzo]

I love them guys at PV, I tell you.

[Jersey_Z71]

Cheers, I am having some similar issues with my bandit 112. Wondering if you would be willing to email those schematics to me?

Does anyone know of a link where you can lookup the serial number?

[Enzo]

PV has no serial number archive.

CONTACT Peavey customer service and ak for your schematic. Include the serial number and any other data on your serial number plate. The exact model name is important. There are several models named Bandit that have one 12" speaker. But "Bandit" and "Bandit 112" are two different models, even though both are 1x12 in speakers. They often add the year after updates, so Bandit 112 and Bandit 112 '89 are different amps. And of course there are also some that are Transtube or TT, and some that are not.