Kustom Quad 200 HD

[Bishop]

I have one of these amps and the issue is that it cuts out once the signal reaches a certain point, which is not much signal at all. Even just the buzz form the guitar can do it at hi volume. It does it on both channels. It's like a gate, where it will cut in and out as the signal varies. You can hear the clicking every time it cuts in and out, from which I think is coming from the JQC-3FF relay. As such, I pulled the shotgun approach and switched out the relay and there was no change. So hear I am, unable to find a proper schematic, (although I did find this one for the 100 HD) and wondering where to go next. Maybe someone has had a similar problem, or this sounds like something familiar? Thanks a bunch.

[soundguruman]

I have one of these amps and the issue is that it cuts out once the signal reaches a certain point, which is not much signal at all. Even just the buzz form the guitar can do it at hi volume. It does it on both channels. It's like a gate, where it will cut in and out as the signal varies. You can hear the clicking every time it cuts in and out, from which I think is coming from the JQC-3FF relay. As such, I pulled the shotgun approach and switched out the relay and there was no change. So hear I am, unable to find a proper schematic, (although I did find this one for the 100 HD) and wondering where to go next. Maybe someone has had a similar problem, or this sounds like something familiar? Thanks a bunch.

Boat Anchor

[Jazz P Bass]

I would try to monitor the relay circuit.
If the signal into the IC is not at the trip point, the ic itself is suspect along with any E caps on that circuit.
The +15 & -15V rails should also be monitored.

[Enzo]

The relay won't turn itself off and on.

Plug a different spesaker into the extension speaker jack. (That should also shut off the internal speakers) Still cut out?

Is there any DC offset on the output?