left channel dies after 5 minutes

[denti alligator]

Thanks, I have tried that. But I will try it again.

[maryc27182]

Hey Sam, I had a similar problem in my Eros (lost a channel after 4-6 minutes, and this was also after having decent operation for months before the problem exhibited itself.)

You may have already re-soldered these, but for me, it was a 2N2907A--one of the solder joints on the legs wasn't solid. I don't use a lot of solder on those little joints, and I guess it wasn't enough.

I ran across this when I was trying to figure out if it could have been the 2N2907A:

https://www.head-fi.org/t/476650/crack-bottlehead-otl/8115#post_13288157

Possibly worth a shot if you haven't already tried it. Good luck.

Mary

[Paul Birkeland]

It probably wouldn't hurt to try a different 6080 as well, but your voltage measurements have me suspicious that replacing the 2N2222 and TIP50 on the offending side might be in order.

DO NOT reheat the solder joints on the LED's.  The HLMP-6000 is hygroscopic and after such a long time out in the open, reheating the LED's with a soldering iron may cause them to crack.

-PB

[denti alligator]

I have swopped out the 6080 and it makes no difference. Are there any joints you suggest I re-try before we try replacing parts?

[Paul Birkeland]

I have swopped out the 6080 and it makes no difference. Are there any joints you suggest I re-try before we try replacing parts?

Both of the transistors on the big C4S board that feed that offending side.  Also check for loose or broken wires.

-PB

[denti alligator]

Done... and for the first time ever I have smoke !!

Turned it off instantly. What to do now?

(Looks like the wire connecting 14 to 20 was melting... if that tells you anything)

[Paul Birkeland]

Measure the resistance between the "O" pad on each side of the big C4S board and ground.  We are getting somewhere I think.

-PB

[denti alligator]

I'm not getting a reading at all on either side.

[Paul Birkeland]

Redo the voltage test with the 6080 removed.

-PB

[denti alligator]

1  -0.23
5  -.156
7  -.091
9  1.392  (and steadily decreasing)
15  244.5
18  96.9
19  96.9
21  245.1

A1  -.187
A3  .859
A6  -.079
A8  .909

B1  -.034
B3  .087
B4  -.113
B6  1.281 and steadily decreasing

all the rest are 0

[Paul Birkeland]

What do you have at terminal 2?  (Your 12AU7 is still plugged in, right?

[denti alligator]

12AU7 is still in.
Terminal 2 is getting no reading. The +/- is flickering and it shows 0.

[Paul Birkeland]

How about terminal 13?  How about B2 and B5?

[denti alligator]

I could check them again, but everything I didn't list was 0 or no reading.

[denti alligator]

B5 and 13 are 0
B2 is 0.002