Guitarist 3/13/2018 7:19 PM
Fender Twin reissue - Channel switching thing
I've been working out a few kinks on this '92 Twin. All that's left (hopefully) is some incomplete channel switching. It won't mute the clean and the LEDs sort of show what happening -or not. Either the Clean (full-bright) and Dirty (right) LED is dim or both are fully lit. I cleaned the input jacks and reflowed all PCB points. Using Fender footswitch nets same behavior. Any ideas or things to check for?

Mods that work well on the dirty channel are" Marshalize the tone stack, kick bypass caps down to 1uF, C24 to .0047, 680pF across last plate cap, added some shielded wire to some grids. Still not perfect but MUCH better.
g1 3/14/2018 12:52 PM
Have you looked at the parallel jacks? If the switches in them don't work right you can get both channels like that.
Guitarist 3/14/2018 4:56 PM
Ok that does make sense. I did spray contact cleaner inside and reflowed the connections. They have the clear cover so I suppose one could pop that off and manually clean each contact. Replacing them wouldn't be much fun.
g1 3/14/2018 6:40 PM
I think those are the 9pin type jacks. Was it working right for you before, or is it something you picked up that needed work? If you don't know the history, make sure someone hasn't replaced the 9 pin jacks with the 4 pin type.