Marshall VS102R Footswitch Issue

[stereomonostereo]

Hey guys,

I'm working on a Marshall VS102R that seems to have a footswitch issue. The panel switches for the channel switching work properly, but when you plug the footswitch into the back, it doesn't do anything. However, if you depress the CLN/OD switch and OD 1/2 switches on the front panel, the footswitch works fine. Is this normal operation for this amp? Or is there something acting up with the footswitch circuit?

http://www.drtube.com/schematics/mar...v100-60-02.pdf

[Jazz P Bass]

As is typical of Marshall schematics, the footswitch function is not annotated.

It appears that the Front Panel Sw1A grounds out Pin 10 of Conn 1 & Sw2A grounds ot Pin 9.

So what does the foot switch do, function wise, unground them?

[g1]

I think this is normal.
If you have the buttons pushed in and use the footswitch, everything works correctly, right?

[stereomonostereo]

Yep, with the buttons depressed everything works as it should

[g1]

It looks to me like SW1a and SW2a are normally closed, therefore grounding. So for the footswitch to work, the switches have to be pressed in so the ground connection is broken.