Vox AD30VT fault

springhead

I've got our other guitar players Vox AD30VT here to play with.  It developed a fault and the shop he took it to gave up on trying to fix it.

It randomly turns the effects on or off - takes the amp in or out of bypass.  Can happen at any time, every couple of minutes or less frequently. 

Just wondered if that's a known fault?  If not I suspect it'll be a bitch to find!

ICBM

Not one I've come across. If it's not the switch itself, all bets are most likely off...

The footswitch doesn't operate it, so it won't be the footswitch jack. (It does Ch1/Ch2 with a latching switch on the tip connection, and Manual with a momentary on the ring, which is a stupid design!)

springhead

I suspected as much.  The bypass button feels ok, could be a dry joint or cracked track around it I suppose, I haven't opened it up yet.

Why would you mix momentary and latching, two different methods, on the same jack for performing the same function?  Weirdness!

ICBM

springhead said:

Why would you mix momentary and latching, two different methods, on the same jack for performing the same function?  Weirdness!

It certainly appears to be how my AD15VT works!

They're not the only ones - Marshall did it on the Vintage Modern as well, but I'm pretty sure the two footswitches were the other way round... it's stupid either way.

DJH83004

Unless you are really lucky and it is something associated with the bypass button, I think you will really struggle. The inputs go directly in to the CPU mounted on the preamp board, which handles all the switching logic. If you haven't already got one, I have the Korg service manual for it, PM me your email address and I will send it over if you need it. Suspect it is either a new board or the bin unfortunately   

ICBM

Unfortunately the only effective workaround I can think of if it isn't repairable is to simply use a setting (eg reverb) with the effect mix turned down to zero and save it in both presets, so you don't hear it going on and off.

springhead

He's given it to me on the basis that it's broke and no good to him anymore.  I thought my son could use it as I remembered it as very occasionally faulty whereas it seems to be much more frequent. 

Like you're preset idea, might try that, and DJH' - PM sent