• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

rivera slavemaster issues

Hi guys.
This time I have a Rivera Slavemaster M60 amp.
It sounds great, btw. The issue with this amp is when the SlaveMaster or effect loop are activated (either manually or with footswitch) only a buzz comes out of the amp.
I cleaned all raleted connectors, relays are working. I think it might be the photocells.
Anyone else had this problem?
I cannot find the replacement part (HTV brand P873-G35-201B). Are there any replacements I can use?