Allright, they sent me a schematic, no parts list so doesn't do any good... It worked fine when I recived it, all new sprague caps, etc.. was reworked.  Then it started haveing problems when switched on.. 1.It has a three way on-off-on switch- the schematic does not show if it has an internal breaker.  2.  The two main capacitors- one checks out, the other shorts out...but I have no part number and you try calling Gibson and see what they say...LOL! "We don't make them any more..."   Anyone know what the cap and switch are and where to purchase them... I'd replace both large caps....I don't see a number on the liners.... Thank you....

I'm looking for a schematic...or if anyone knows the proper fuse for this amplifier.....I took out a Buss MTH4 and replaced it with a fast burn 5amp (all I had on hand), which works fine -Cleaner for some odd reason with no tube drain sound on shutting off.
One great sounding clean amp...expermented with a few 12ax7 tubes and found the old RCAs give it a warm, even sound-newer brighter with a more fender solid state sound...didn't know they would make such a vast sound difference in overall use...  Have another amp problem I'll post..

OK, its the HD mixer, but I can't find any information on the three way switch... does it have a bulit in 15 amp fuse?  Why does it need it?   Can I rewire to a two way safely or is there a specific reason for this switch?  ...  THank you

http://www.gibson.com/Files/schematics/G100A.pdf     This is as 'close' as they have on it..and not the same switch..have a 6 pole three way...on/off/on
here is another guy with problems, but: mine is cherry inside and out...5 pic down the two large caps-..I same # but get two different readings, in fact the one where the orange/yellow lead goes has twice the resistance for some reason....that is the only anomaly I can find...
AFTER CLEANING-RE-SOLDERING  CHECKING GROUNDS - HAVE CONSTANT, BUT CLEAR, HUM WHICH RELATES DIRECTLY TO THE VOLUME-MASTER AND CHANNEL-TONE/REVERB HAVE NO AFFECT AND CAN HEAR MIC, BUT HUM IS TOO LOUD FOR RECORDING OR PERFORMANCE

1.While there are six leads coming into the on/off switch ( which I don't understand the significance of , can I replace it with a two way?  While it checks out, this is where the problem seemed to start.   Tapped it and hum would leave...then simply continued after intervals getting closer and closer.
2. checked breaker/3.4 plunger type which does engage shutdown when pushed down- red plunger is in the out position and active.  It does not hold on a 'down' position and do not know if this is normal.
Im in TN and have breakers and power strips on everything...we are by a power station and have spikes all the time...fries cable box's (they are used to giving them out like m&ms some days), one computer.. had to get an ATP 200 for the computer as conventional's won't handle the load.  I don't leave the PA plugged in, but a spike could have occurred while playing.
Thank you for your time..

Thanks, YOUR RIGHT so far- went back through starting with Transformer leads...so far found 2 GREENed corroded wires under the solder at connection bar from transformer..stripped back, cleaned, sanded bar..fluxed/rewired..found one Ground terminal poorly soldered/dirty-wouldn't respond to re-heating-cleaned etc......going through rest...1972 and probably stored for a while at some point in time...Thanks again, we'll see where it ends up... that's 3 I missed as I presumed they seemed tight and had continuity..novice mistake...

...and note:  can hear mic...but its a buzz-not a feedback hum...which increase's with turning ANY volume knob, from master to what-ever channel -including not plugged into...

Ok, been reworked once...sprague caps etc..but out of nowhere started feedback-tap on faceplate by on/off 3 way 6 pole switch...and hum would stop- then intervals became closer.. checked everything, switch OK, breaker OK, caps- one seems to register higher than the other on the duel 1013-725 50vcds... but also now_ transformer hums, with or without speaker... ideas?  also:  How to test transformer?  And the gp100 schematic does not show the same switch...