This amp has not been used much and was working well when I fired up the system to hear my new SVS Prime bookshelves. thanks again to everyone here who helped me find speakers.
So, I did the yellow sheet mod, which went well. Next, I upgraded the speaker posts replacing the originals with a set I got from Roy. Just a single pair for an 8Ω tap.
Was careful since I never did this before.
It has been some years since I had cleaned it, so Deoxit on the bias pots, cleaned tube sockets using soft pipe cleaners with a little Deoxit on the ends, cleaned tube pins gently with a fiberglass pen scrapper (or whatever it's called). worked well. then of course cleaned and polished the chassis, which seems to be in decent condition.
Before I put it back into the system, I looked things over and noticed that the right, rear coupling cap was a little loose. I opened it up, and found when moving the cap, the connection would separate from the board, and there was a small break at the trace. damn. I must have done some bonehead thing to cause this. So, I soldered it back, (really wasn't confident in the way it turned out) and hoped for the best.
Did have my doubts and, well, put it back in the system, turned on the preamp but did not have a source on and waited a bit. Switched on the amp and did hear a single pop from the right speaker.
Checked the bias right away since I had cleaned the pots and didn't know where it would be at. damn, on the right channel it read 6VDC (did I misread it, could it be that high?) and adjusting the pot did nothing. Quickly checked the left and was able to set it fine at 1.4VDC just to get close so I could get back to the right channel. Then noticed the right rear output tube was glowing bright.
Shut it down fast.
What would cause this condition?
I am not a tech, and don't know what causes what. (?)
Now to me, it seems to correlate with right rear coupling cap issue, as I thought might be a problem.
Before I make things worse, thought I should get some input as to whether I am on the right track.
Thank you for your patience reading this and would greatly appreciate any help.
Last edited by raudio44 on Sun Jul 17, 2022 9:07 am; edited 1 time in total (Reason for editing : correction)