The g33000 has arrived

bktheking

Gitter Done!
Vintageplus' g33000 amp section showed up on Friday. I will post pics when I have a moment. I'm going through the blown channel , right channel, so far all my checks pass less 4 blown outputs. The left channel board was cracked and attempt to repair had been made, it was terrible. It's since been redone, yesterday, very carefully.

Mistakes in the SM- D05/06 show as 10D1 and D07 D08 as the MV103- this is reversed. To make matters works, whoever worked on it did the 3 diode string on the other channel to replace 10D1- i'm sure that would make bias go wacky.
 
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Oh boy..sounds like a mess! If you need any pics/info from mine just let me know. It probably needs a good cleaning anyways...
 
It is, i'm about to post pics- toby, I need to see pics of the covers installed on the driver boards, good ones- all the ones on the web aren't close enough and the SM doesn't show squat.

We'll start off with the specimen.

lFy6Ga.jpg
 
Right side channel, fuse 1 and 2 blown, 10A. F1 had a 20 installed, 2 was a 10.
You'll notice whoever worked on it went crazy marking everywhere with nail polish, I guess writing it down in on a notepad was too much work.

z1z1Xz.jpg


Since 24v zener's are difficult to find, let's put 3 8v's together.

Xg30ew.jpg
 
4 of the 8 blew up, already been worked on. The pro replaced all the transistors as a matched set- right.

mK5p45.jpg


Who needs a fan? Right?

5t9AvL.jpg


Also decided to epoxy the right channel driver board connector.

aEx7Hz.jpg
 
Attempted repair- the bottom of the board is cracked- left channel driver board.

S5wfnV.jpg


Board removed, crack revealed. Note the replacement resistors, carbon comp.

0fAsJc.jpg


After removal.

8w1isF.jpg
 
Top side of the PS board that driver board plugs into. More traces to redo.

pz9GXi.jpg


Mock MV103 installed where a 10d1 should be.

F5lP0O.jpg


Left Channel outputs, too bad the screws are wrong- UPDATED***ALL BLOWN AS WELL.

v5ef0b.jpg
 
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What a mess. All the original outputs are gone and not even replaced consistently side to side. For the driver board to be cracked like that, I'm guessing someone hit the board when the tin cover was off. Fortunately these big Gs are pretty easy to work on.

- Pete
 
At least its in the hands of someone with the skills to fix it right. Nice work on the repair.
 
Looks like you're going to have your hands full for a while there but I'm certain the patient will make a full recovery.

Considering what these are worth, why in the hell would the last owner have taken it to such a hack for repair?
 
I have no idea. Supposedly it was a shop in BC. The work done is an absolute joke. Wrong screws, missing covers, broken board, lifted traces EVERYWHERE, wrong subs used, the list goes on. I wouldn't be able to live with myself if I did this to someone's prized audio piece.
 
What a complete mess!!

Wish I had it on my bench, I love working on these amps......

You'll enjoy it, looks like you already have been...


Whats the bet the input cables were unplugged with the power amp actually powered up.
You cannot do that with these amps as they are wide open, no gains to turn down....
And with so many dodgy repairs, it just gave up the ghost.....

You probably could use the Motorola/On-semi MJ15003/15004 as a replacement....

Nice job on the repair to the circuit board too, not an easy job....

I'll be watching this with interest...
 
When I went to look at the unit, the owner had the power amp section on without the inputs plugged in. Maybe your theory is correct Kev. Sad to see the obvious lack of caring on the previous techs behalf. Brad is the man for the job though. He can bring anything back to life.
 
So he had the umbilical connected but no inputs? Weird way of doing things. I still have to test the main caps, the large metal diodes are good.
 
I was thinking these:

863-MJ21193G pnp to-3 250v 16/30A 250W 8-75hfe 4mhz
863-MJ21194G npn to-3 250v 16/30A 250W 8-75hfe 4mhz
 
Good thread. Good to see expert restoration being applied to such a prize piece.

As an owner of good audio gear that will sooner or later need work, I would like to see a good referral thread somewhere on AK to help us find reputable techs in our areas so that we do not end up with the sort of situation shown in this thread.
 
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