VOX AC10C1 reissue giving me fits

[Randall]

Amp comes in for awful distorted tone, and cutting in and out. I find I can make it do it by probing the board, almost anywhere. Dislodge the board and isolate it to a very touchy treble pot. OK, resolder, same. Remove pot, take apart, nothing looks amiss. Put it back in, same. A little push on the shell or shaft cuts out and makes noise. Pull it out again,along with the bass pot of the same value and swap them. Treble pot still acting the same, and now bass pot does nothing unless I push on it. Thinking maybe the dual sided board has issue, so I solder the pot legs on both sides. Still does the same thing.

So now I wonder what to do? I can't find a schematic, and this layout is a bear to work on. The amp has only been out a year or so. What am I missing?

[xtian]

When you put pressure on one component, the board flexes, activating the intermittent connection. Tough to find! But you can divide and conquer just like we normally do, to limit the likely possibilities.

[Jazz P Bass]

Shouldn't this be a warranty station repair?

[MarkusBass]

I would compare it with the old version of the amp: www.thetubestore.com - Vox Amp Schematics

Mark

[Randall]

I suppose by now I have voided any warranty there may have been/if had been. And I've already looked at the old version, and this amp is a modern chinese factory version of a 1960 amp. Not the same thing.

[nosaj]

I suppose by now I have voided any warranty there may have been/if had been. And I've already looked at the old version, and this amp is a modern chinese factory version of a 1960 amp. Not the same thing.

If you are adept with a soldering iron it should look just as it did before you opened it. Can't hurt to try the warranty route if you bill by the hr.

nosaj

[Jazz P Bass]

I suppose by now I have voided any warranty there may have been/if had been. And I've already looked at the old version, and this amp is a modern chinese factory version of a 1960 amp. Not the same thing.

Why would opening the amp void the warranty?

And, yes, the reissue is way different in the layout.

[nickb]

When you put pressure on one component, the board flexes, activating the intermittent connection. Tough to find! But you can divide and conquer just like we normally do, to limit the likely possibilities.

xtain has the way forward.

To avoid working blind scope various points along the signal path as you flex so you can narrow where the breaks it both mechanically and electrically. It could be a hairline crack in a PCB trace.

[Randall]

Because I have soldered both side of the board to the pot legs in an attempt to make a better connection, which did not work. So now I am in danger of lifting pads. I wish I could find a schem, then I could run jumpers and leave the pots in. What a PIA.

Anyone have experience on getting parts from VOX? I may be buying the guy a preamp board if I can't fix it.

[nosaj]

Because I have soldered both side of the board to the pot legs in an attempt to make a better connection, which did not work. So now I am in danger of lifting pads. I wish I could find a schem, then I could run jumpers and leave the pots in. What a PIA.

Anyone have experience on getting parts from VOX? I may be buying the guy a preamp board if I can't fix it.

If your in danger of lifting pads maybe you should be trying a hotter iron so that you have less contact time on a joint, maybe?

nosaj

[Jazz P Bass]

Because I have soldered both side of the board to the pot legs in an attempt to make a better connection, which did not work. So now I am in danger of lifting pads. I wish I could find a schem, then I could run jumpers and leave the pots in. What a PIA.

Anyone have experience on getting parts from VOX? I may be buying the guy a preamp board if I can't fix it.

Clean up the flux on the pads that you resoldered.

Scuff up the solder work with a toothbrush.

Put it back together & have your customer take it to an authorized repair station.

There may be a manufacturers defect that the factory would like to know about.

[olddawg]

Clean up the flux on the pads that you resoldered.

Scuff up the solder work with a toothbrush.

Put it back together & have your customer take it to an authorized repair station.

There may be a manufacturers defect that the factory would like to know about.

Absolutely. Alcohol works fine. If it's under warranty they will cover it unless it is horribly buggered up. Who's to say it wasn't a factory fix/touch up before it was sold. Happens all the time. It may simply be exchanged.