gibson GA-20RVT

[Andy Le Blanc]

picked up a a little gibson minute man at a blues jam over at the Solon Hotel
to fix for a guy..... "no I really want you to take a look at my amp".......
and.... " well, I got money"....... was all it took.......but you gotto know the guy
glorious wreck a man..... stoned speechless ..... leaveing a trail of nattie lite
cans like a trail of bread crumbs....... constantly hand rollin cigs.... hes the
gut who clears the place every week with out of tune renditions of the who's
"wont get fooled again" with this awful sounding little amp....... which now
resides....... stinking of ash tray and bar fuzz.... on my bench
Now I know the guy dont got nothing...... but it was his dads old amp and
despite his raucous nature (laidback) he loves music so I said "sure I'll take
a look at it"

I figured it was tubes.... so I checked the commonly available scheme online
and started to go over it.... and it wasnt too bad..... it had had some work before
and needed a couple filtercaps in the power supply.... cleaning..... socket tention
but it sounded like it was gonna die.....?????.....I know the guy aint got nothin
this model has 6eu7's.... so I start priceing..... and find Ill end up eating
the cost of the repair.....ok.... whats cheaper, buyin 6eu7's or converting
the sockets to 12ax7.... I dont want to its all original..... but if hes gonna
get nothin but dissapointment I've got to cover all the bases.....
and the amp got that special turd tone.... so I start counting sockets with
filament leads dressed for a 6eu7.... and find that theres not enough of them
as compared to the scheme.....??????..... so I start going over gibson schemes
and the only comparable unit seemed to be A GA-35RVT lancer with pretty much
the same curcuit but with a 12ax7 in place of one of the 6eu7......
fixed.... nice amp...... and the guy can afford a couple tubes......
funny..... it looked like it had been retubed with the wrong tube.... maybe
it hummed, maybe the varience from the manufacturer has been a problem for a while.....

when I left the jam he was leanin against a car in the parkin lot, sucking
on a rollie, "YEP.... my second wife....she's greedy... I got no alimony"
and the guy next to him chimed in with " thats caused you aint bonified".....
"touche".. he said ..." you know that means to touch"

[Phil_S]

Andy,
For starters, there are at least two models of that era inside the same cosmetics. It sounds like the one you have is the one I have. Mine had a ton of problems. I've been over every inch of it and probably know quite a bit.

I was unable to un-glue the schematic from the cabinet wall, so I painstakingly hand copied it so I could have a bench reference. I know of at least one error, but it's been a while -- I think R30 should be 3.3K not 5.5K.

Have at it. I'll be happy to take private email on this or do it here. PM me for starters if you are interested in taking it off line.

Getting though the subtext of the owner, I don't think I saw any description of the problem(s), of which I expect there are many.

Regards,
Phil