Sunn Enforcer Channel Switching Not Working Properly

[lovguitar]

Hello,

I have a Sunn Enforcer combo that I have owned for a number of years.  It has been reliable, but the channel switching recently stopped working properly.  The footswitch leds properly indicate a or b and a plus b, but the b channel on the amp never shuts down.  The led stays lit and the channel remains active, so my only choices are b or a plus b.

Any ideas as to what may be wrong?

Thanks,

Paul

[loudthud]

Step one would be to open up the foot switch and check/verify the switches with an ohm meter. I can't find any schematic of the footswitch itself.

[lovguitar]

I think that the footswitch itself is OK.  I opened it up and the components are simple (diodes and resistors in addition to the switches themselves) and they all seem to be fine.  In addition, the LEDs on the footswitch switch properly.  It seems to be on the amp side that there is a problem.  Either a relay that is not relaying or an IC that is not.

Thanks for your post!

Paul

[mckinnon audio]

  Hi there,if you look under service manuals on this home page,you'll find a complete manual and schematic.Good luck,Mel.