Gibson Super Goldtone schemo

[Mars Amp Repair]

Hello folks,
Does anyone know where a guy can find newer gibson schematics? or perhaps anyone have one? The way this one is set up, the only way to do any tracing would be to pull out the main board & follow the traces...it's a 2 sided pcb.

Issue is channel 2 has way less gain than channel 1. Trying to follow the minimal traces on the exposed side of the board or signal tracing the known pins on the 12AX7's is yielding no help. It has switching transistors all over the place for selecting different functions too

Thanx, glen

[Bruce / Mission Amps]

Originally Posted by Mars Amp Repair

Hello folks,
Does anyone know where a guy can find newer gibson schematics? or perhaps anyone have one? The way this one is set up, the only way to do any tracing would be to pull out the main board & follow the traces...it's a 2 sided pcb.

Issue is channel 2 has way less gain than channel 1. Trying to follow the minimal traces on the exposed side of the board or signal tracing the known pins on the 12AX7's is yielding no help. It has switching transistors all over the place for selecting different functions too

Thanx, glen

Maybe this will help Glen:

[Mars Amp Repair]

Thanx Bruce,
It was nice to finally meet you over at Gravity that day...I find myself busy nearly 12hrs a day & Satdays I'm running doing deliveries. I've got about 4yrs before my son can start doing that part for me ;-]

I got on Gibson's site (I guess I just don't expect much from the mfgs sometimes) & it looks like Gibson is fairly tech-friendly, too. Nice that some of these manufacturers are realizing that it's better to make it easier to have their equipment repaired than to keep all this info 'secret' .

A good example would be QSC. They have the most friendly tech support I've ever experienced. I guess they don't authorize service centers anymore or at least they're not authorizing any addl ones, BUT, their tech support is superb. You get on the forum & e-mail the main guy there & within a day, you have an answer e-mailed back directly to you. They also make all their manuals & also as important the circuit expanations available on line for anyone.

Anyway, it helps a great deal.

your pdf will help alot..too bad they don't have the screenings of the boards, too. Ah, but I digress...thanx again, glen

[Mars Amp Repair]

Problem solved. was a shorted plate load bypass capacitor..I guess more accurately termed a 'snubber' 680pf cap.
Of course in retrospect it should have been obvious when the plate voltage is the same as the supply, however somehow the signal albeit not present at all on the plate, was somehow sneaking past this stage & actually putting out a fair level of sound.

Thanx, glen

[Bruce / Mission Amps]

Originally Posted by Mars Amp Repair

Problem solved. was a shorted plate load bypass capacitor..I guess more accurately termed a 'snubber' 680pf cap.
Of course in retrospect it should have been obvious when the plate voltage is the same as the supply, however somehow the signal albeit not present at all on the plate, was somehow sneaking past this stage & actually putting out a fair level of sound.

Thanx, glen

Right... you'd also get a similar B+ measurement if that same tube's cathode biasing resistor goes open.
Yeah, nice finally meeting up with you too, sorry I couldn't spend more time but I had a bunch of stuff to do that day too.

Glad I could help.