Recent content by Audiobro

Got it! Just needed a bit of Rubber Renue on the pinch roller and idler tire. Works like a champ now.

I recently picked this unit up and it seems like a pretty nice deck. It has one problem, it won't play. I can make it play by lifting up on the pinch roller. Maybe the tension spring is shot?

I had started to think that it was wrong. It didn't make sense to take the reading from J724 as it's a 14v tap. I am able to adjust the voltage to 35v with no problem measuring between J722 (+) and chassis ground. Thank you very much for clearing that up!

I have a 2238B that I cannot get the power supply voltage above 28v, when it is supposed to be 35v. I have replaced nearly all the components within the adjustment circuit, along with the main filter caps. I must admit that I do not understand how this circuit controls the power supply. The...

OK, so if I power it up and it doesn't catch fire, I should replace it. I hope you can excuse my sarcastic attempt at humor. But it seems to me that I do not know that TR632 is faulty and since I cannot find any specs for a 2SA941BL, I cannot properly test it. My little transistor checker says...

If I simply remove TR632, won't that eliminate protection of the "crowbar" circuit?

Yes, this is the test procedure I had used to initially set dc offset. That was when the unit was working. Presently, I am tracing back the -30v rail to see where the failure is. I have no base current on TR626 and 628, which should supply the -30v.

Why yes, as a matter of fact I have lost the -30v rail.

I had completed a full recap on this and reflowed a good deal of joints. It worked for a few days then would shut down. Initially, I thought it was a problem with the protect circuit, in reality, it is functioning fine. It seems to be triggered by the 1.5v of dc offset I am reading at the test...

That's the problem, the schematics and board view contradict how they are installed. Thanks, at least I know the Rubycons are original.

On first look, a 1K resistor near the backend of the left amp was completely melted. I replaced that, and it melted again. Next, I started pulling parts in line with it and tested them. I found a couple transistors and a couple resistors that were bad as well. I replaced those and still had the...

I've checked about half of the left amp board and just discovered today that there is damage to the right side as well. I was kind of leaning toward the power supply as a common denominator. I was able to switch power on after disconnecting the right amp. But I have to resolder the 80v caps back...

Yes, but the 100v caps have the positive connection on the right and the 80v pair have the positive on the left. Both pairs are connected in series.

The person I bought it from had stated that it had been recapped. I don't think it was. But, the Rubycons filter caps has me questioning whether they had been replaced. Also, someone did a lousy job of replacing the protect relays. Mostly I wanted to clear up the discrepancy on the polarity of...