Marshall GM dfx 30 Power Switch pinout

Thread Starter

Adam Monarch

Joined Mar 17, 2019
Marshall gm 30 dfx
I figured out the pinout. However when I connect the power chord to an isolation transformer the transformer trips the circuit breaker when I turn the amp on. The older switch which I removed had some burn marks on some of the pins. What could be the reason that the amp has this problem? Attached is a picture of the old switch.



Joined Jan 8, 2017
With nothing connected to the output side of the switch measure the resistance between the wires that go to the isolation transformer with the switch in both the on and off positions. Report the results. Also show us a picture of how you have connected the input and output wires from the switch. As you have not provided a manufacturer and part number for the new switch no one will be able to tell you the pinout. Without that the only way to find out is to do continuity tests.