Jazz Chorus 77 powers up but no sound

[akblacwel]

I've recently acquired a JC-77 on the cheap. It seems to have some problems though.

When I plug my guitar up to the hi input, it just makes a loud squealing noise. The low input barely has any volume to it no matter how much I turn up.

Anyone have any ideas where I can start to troubleshoot this issue?

Thanks

KB

[Jazz P Bass]

A good place to start is to find the schematic.
Then test all the power supplies.

[mozwell]

maybe this is the one you are after