I just noticed this now! I will post some pictures when I get home tonight.
I have it more or less back together now. The polyeura coating looks good.
Had a bit of a mishap, I had a NPN in a PNP socket, ruined a set. I just got confused, it had 2 brands of transistors on one channel. Other then that everything else appears to work. Should have had a bulb tester hooked up and I might have saved them. Although they were really old looking Motorola 2N3773/2N6609.
The other transistors are newer On-Semi MJ21196/MJ21196.
I was thinking of ordering 8, but in reality one pair would get me by. The price is OK for all 8, it just depends on what I spend on filter caps. From what I read these devices are good until they are not good.
Is there any point in replacing the other good newer output transistors?
Earlier on I mentioned the caps were 7500uf@50v in series for effective 3750uf@100v. It looks like I gapped out, due to the dual rails, I actually do need the 7500uf@50v replacements.
So I will have to see what I can come up with for caps. A quick glance at DigiKey shows "replacements" at $22 each.
Another option for outputs is 2ST5949/2ST2121 however DigiKey is out of stock at the moment.
Here it is more or less back together.
The original power switch was shot on one side. I just made up some jumpers for testing in the meantime. The replacement needs to be fairly robust.
I also have to change a couple smaller lytic caps on the amp boards, although they measure OK. Everything else has measured OK so far.
I broke on of the leads of a clipping LED, so I got to pick out a new pair from the junkbox.
I took a tracing of the 3Bryston logo on the front. I really debated covering it up. The faceplate was a little rough and since it took so much effort to clean it up I wanted to go all-out. I might just paint a larger "3B" rather then the full 3Bryston.
So aside from a faulty power switch and me ruining a pair of transistors, it was a good purchase. I should have my mind made up on the filter caps and hopefully order them tomorrow.
The original power switch was shot on one side. I just made up some jumpers for testing in the meantime. The replacement needs to be fairly robust.
I also have to change a couple smaller lytic caps on the amp boards, although they measure OK. Everything else has measured OK so far.
I broke on of the leads of a clipping LED, so I got to pick out a new pair from the junkbox.
I took a tracing of the 3Bryston logo on the front. I really debated covering it up. The faceplate was a little rough and since it took so much effort to clean it up I wanted to go all-out. I might just paint a larger "3B" rather then the full 3Bryston.
So aside from a faulty power switch and me ruining a pair of transistors, it was a good purchase. I should have my mind made up on the filter caps and hopefully order them tomorrow.
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I still have not decided on filter capacitors.
I might use a pair of smaller caps to replace each large one, or maybe jump to a single 10.000uf cap.
The reason being I'm looking at around $120 to replace the capacitors with ones similar to the original 7500uf 50v.
It just seems like a lots to pay for that amount of capacitance.
I might use a pair of smaller caps to replace each large one, or maybe jump to a single 10.000uf cap.
The reason being I'm looking at around $120 to replace the capacitors with ones similar to the original 7500uf 50v.
It just seems like a lots to pay for that amount of capacitance.
With $120 you can get very good caps like 10.000uf 125c X 4 Mundorf audio grade. you can get them at Partsconnexion in Canada.😉
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