rufleruf
Poor Impulse Control
The previous owner did all the work you see below with a few exceptions: the output coupling caps were a mix of brands and values, 2 .039's, a small silver polyester .047 (I think) and a random old .047. I swapped in the 4 orange ones seen now in .047.
One of the output transformers was an original early 6K item, the other was a later 10K item. I bought another early transformer last week on the bay, and installed it last night. The replaced Transformer is the one closer to the MPX unit.
I brought it up on my variac and when I got to the point of playing, I got a loud hum from the side I swapped the transformer on. I turned the speakers off and found there to be good even sound going into the volume pot. While testing, the load resistors started to smoke a bit and the output tubes on the loud hum side were just starting to red-plate. I checked the voltage to pin 9 on the output tubes for both sides of that output transformer and found roughly the 395v shown in the schematic.
What gives? I'm thinking there is something wrong in the amplifier section on that side... anyone see anything obvious I missed?
One of the output transformers was an original early 6K item, the other was a later 10K item. I bought another early transformer last week on the bay, and installed it last night. The replaced Transformer is the one closer to the MPX unit.
I brought it up on my variac and when I got to the point of playing, I got a loud hum from the side I swapped the transformer on. I turned the speakers off and found there to be good even sound going into the volume pot. While testing, the load resistors started to smoke a bit and the output tubes on the loud hum side were just starting to red-plate. I checked the voltage to pin 9 on the output tubes for both sides of that output transformer and found roughly the 395v shown in the schematic.
What gives? I'm thinking there is something wrong in the amplifier section on that side... anyone see anything obvious I missed?