Channel Switching problem on Carvin Belair amp

[jnsfoto]

Amp, Carvin 50 watt Belair.

The problem, I can not go from clean to soak channel using the foot switch or panel switch. Sometimes it will go from soak to clean by itself.

New to the forum, I have searched and could not find any postings with the problems I have. If it is here I apologize, and please post a link for me.

[Alex R]

well there is a problem with the switching circuit which would have to be traced.

It switches using relays. One may be faulty. But probably the first thing I'd check would be the power supply to the relay coils, which produces 3-5vDC by rectifying the heater AC voltage. Or maybe the panel switch, it seems to stay in circuit with the footswitch in.

schematic here

[Zouto]

Well, I have a similar problem with a Carvin Belair: the relay sometimes works fine, switching from clean to soak, sometimes it switches to soak with a massive volume drop, the signal is absolutely too low. I replaced the panel switch and wiring , checked the footswitch jack with no success. The reverb relay is working fine, so I think the channel switching relay is faulty. What type of relay is the right replacement, there‘s no printing on both relays?
Thanks for help
Zouto

[The Dude]

It would be odd for there to be no markings on the relay, but it that's so, measure the voltage at the relay coil. You should be able to figure it out from there. Just look for a relay with the right footprint, voltage, and switch type (SPST, etc.).