Gibson Vanguard GA77RVT Troubles - Reverb on Normal Channel

[Wittgenstein]

My buddy has a Gibson Vanguard GA77RVT like the one Scotty Moore used to play. This is a strange one that has an OC2 rectifer, two x 6L6 power tubes, four x 6EU7's and a 12AU7 according to what someone wrote in pencil on the back panel, but sadly there is no schematic.

When we first fired it up, it would only have volume if you turned up the reverb knob, and the more you turned up the louder it got. We gave it a cap job, 3 prong cord, changed the obviously blown out capacitors, and swapped tubes and now it sounds much better, however now you get reverb on the normal channel when you turn up the reverb knob. It is a rich full reverb that is even stronger than on the effect channel with tremolo and reverb, which is very weak, and not quite as loud. The tremolo does not bleed over to the normal channel, just the reverb.

Any suggestions on where to begin, or what could cause this?

[Enzo]

Maybe?
http://bmamps.com/Schematics/gibson/ga77ret.pdf

Only one I spot with a Vreg tube. OA2 OC2 and similar are not rectifiers, they are voltage regulator tubes. They are essentially a tube version of a zener.


Gibson amps are notorious for not matching schematics, sometimes the guts of a Gibson are really an Epiphone circuit or vice versa. I have one model with four different factory schematics, plus two more different ones I have drawn myself from the chassis. SIX!

Someone may have modified the amp for reverb on both channels, just a jumper situation.

otherwise, like any amp, I'd put a signal into the front and trace it through the stages.

[lowell]

I've got one of these GA77RVT in. Do you have to remove the speaker or baffle to get the chassis out? This has 1x15 speaker.