I have a pair of M100's here that were in need of new tubes. They did play really fine after the retube for some time.
During the last power up, on of them started making wild popping sounds through the speaker and the regulator tube (6550) was sparking. Whoops.
Then the built in smoke came out before I could turn the amp off.
It was R124 that burned down. (All other associated resistors are fine)
Replaced it along with a fresh 6550 in the regulator position and tried again.
...to no avail.
When the amp powers on, there is a rattling sound from the output (speaker) even before the screen light turns on. (It will start as soon as the power tubes are somewhat warmed up.)
When turning it off, it will make oscillating noises.
I did try to replace the ecc81 and 7044 in the regulator as well but that did not help, just as replacing the output tubes (bias all the way down) did not help.
I know there are a couple of M100 experts over here. I would be grateful if one of you could chime in. Many thanks in advance.
During the last power up, on of them started making wild popping sounds through the speaker and the regulator tube (6550) was sparking. Whoops.
Then the built in smoke came out before I could turn the amp off.
It was R124 that burned down. (All other associated resistors are fine)
Replaced it along with a fresh 6550 in the regulator position and tried again.
...to no avail.
When the amp powers on, there is a rattling sound from the output (speaker) even before the screen light turns on. (It will start as soon as the power tubes are somewhat warmed up.)
When turning it off, it will make oscillating noises.
I did try to replace the ecc81 and 7044 in the regulator as well but that did not help, just as replacing the output tubes (bias all the way down) did not help.
I know there are a couple of M100 experts over here. I would be grateful if one of you could chime in. Many thanks in advance.