el-84 red plating

[ecoman35]

I have a vc2110r that has started red plating 1 of the power tubes and sounding staticy. It blew the main fuse when i connected my les paul replced the fuse but one socket is red plateing tried swapping tubes still doing the same thing so I guess its a amp problem. Any help would be appreciated I am fairly new to tube amps but have done a lot of electrical work.

thanks, scott

[Jazz P Bass]

Crate Vc210

When you swapped tubes did the red plating follow the tube or is it staying at one socket?

[ecoman35]

stayed at the same socket. not a tube issue.

[Jazz P Bass]

Crate VC2110R

I posted the 2110R schematic.
Go over the test points around the output tubes & the phase inverter.
You may have lost a screen or grid resistor.

[oc disorder]

It could be shorted turns on one side of the output transformer.
Try switching it round - ie J6 from transformer to J8 on board and J8 from transformer to J6 on board.
See if the problem changes to the other socket.
Also measuring the DC resistance between J7 & J8 and J7 & J6 should give a rough idea.
They should be relatively close.
And as JP Bass said check the resistors around the socket particuarly R24 and R25 they should be 100 ohms.
Actually after looking at the diagram check R26 should be 470 0hms.
Looks like the screen grids are at a higher potential than the plates..!