Amp channel switches by itself?

[Mike Schram]

What would cause my Jubilee to change channels by itself? Faulty cord ?

[Rosewood]

Could be a relay going bad or relay voltage supply problem. If a footswitch had an intermitten connection I guess it could trigger it. If it does it with out a footswitch I would check the relay voltage supply first.

[mwm523]

I had a Marshall TSL that used to do this. It was a relay.

[Mike Schram]

Thanks guys....where can you buy Marshall relays?

[Jack DeVille]

Thanks guys....where can you buy Marshall relays?

it may be a production/off-the-shelf job. pop the chassis out and check if there are any numbers on the relay. do a google search for any numbers found and turn on your iron.

best of luck!!

EDIT:

be sure that you have a faulty relay before you go through the hassle of replacing it. obtain a schematic by any means necessary and analyze the channel switching circuit. force the unit to display its failure and compare failing circuit behavior with predicted behavior. if you want to just shotgun the diagnosis, perform GMs ol' screw driver test (beat on all relays with the butt end of a screwdriver). the failing relay will hopefully exhibit its fault under the 'stresses' imposed by the screwdriver.

i have a HRDx in the shop right now that 'changes channels on its own.' i found a intermittent open in the coil of the channel switching relay.
also have a red-knob twin in right now that was doing the same thing, although this one had a failed LDR assm.