Servicing a Fender SRM 6302 PA Amplifier.

[DrNomis_44]

Update 6:


Decided to do a relatively minor mod to the Send and Return sockets in the Diecast box on the end of the FX Loop breakout cable, this basically involved soldering a 2M2 resistor from each socket's tip connection to circuit-ground, this was done to stop loud popping-noises coming through the amp due to a couple of coupling-caps in the FX Loop circuitry, one end of the caps was tied directly to the tip contact of their respective socket, this provided no path for built-up charges on the caps to leak to ground, adding the two 2M2 resistors now provides the path to ground without a detrimental effect on the signals in the FX Loop, I've tested it out and it is still working perfectly.

[Marcel]

The wonderful static discharge abilities of the faithful 2M2 are sadly under appreciated.

I unsuccessfully tried to get a 2M pot today from Jaycar.... Seems RS is the only reasonable alternative...

[DrNomis_44]

The wonderful static discharge abilities of the faithful 2M2 are sadly under appreciated.

I unsuccessfully tried to get a 2M pot today from Jaycar.... Seems RS is the only reasonable alternative...

For sure, I could have used a couple of 1M resistors, but when nothing is plugged into the send and return sockets, the two resistors would effectively be in parallel with each other, giving a load-resistance of around 500k, with two 2M2 resistors the load resistance is around 1.1M, both 500k and 1.1M would constitute a relatively light load to the signal coming from the preamp, but since the preamp signal is buffered by a 2N5087 PNP transistor configured as an emitter-follower stage, the loading would have been inconsequential, I went with the 2M2 resistors anyway.