Bringing this old post back from the dead! I'm working on the same unit with the same symptoms , same offset in the same channel even? Would anyone know what exactly fixed this unit? I've gone over the boards at all the heat zones with fresh solder. Checked transistors and small caps but everything seems in order?
Q214
E. -5.57v
C. -91.7v
B. -5.65v
vs.
Q213
E. -2.55v
C. -91.7v
B. -3.12v
Q220
E. -3.87v
C. -27.4v
B. -4.33v
vs
Q219
E. +53.2mv
C. -27.4v
B. -0.470mv
Q218
E. -3.89v
C. +27.5v
B. -4.33v
vs
Q217
E. +54mv
C. +27.5v
B. +57mv
E. -5.57v
C. -91.7v
B. -5.65v
vs.
Q213
E. -2.55v
C. -91.7v
B. -3.12v
Q220
E. -3.87v
C. -27.4v
B. -4.33v
vs
Q219
E. +53.2mv
C. -27.4v
B. -0.470mv
Q218
E. -3.89v
C. +27.5v
B. -4.33v
vs
Q217
E. +54mv
C. +27.5v
B. +57mv
Here's the outta whack voltages I get from the output transistors. Even numbered transistors are the problem channel.
Q214
E. -5.57v
C. -91.7v
B. -5.65v
vs.
Q213
E. -2.55v
C. -91.7v
B. -3.12v
Q220
E. -3.87v
C. -27.4v
B. -4.33v
vs
Q219
E. +53.2mv
C. -27.4v
B. -0.470mv
Q218
E. -3.89v
C. +27.5v
B. -4.33v
vs
Q217
E. +54mv
C. +27.5v
B. +57mv
( Excuse my double post)
Q214
E. -5.57v
C. -91.7v
B. -5.65v
vs.
Q213
E. -2.55v
C. -91.7v
B. -3.12v
Q220
E. -3.87v
C. -27.4v
B. -4.33v
vs
Q219
E. +53.2mv
C. -27.4v
B. -0.470mv
Q218
E. -3.89v
C. +27.5v
B. -4.33v
vs
Q217
E. +54mv
C. +27.5v
B. +57mv
( Excuse my double post)
Last edited:
I have the same problem as described by OP. It seems like a problem on the input board, as I get the same low DC offset on the output terminals when the input board is pulled, but the left goes to ~300mV with the input board attached. I re-capped the input board, but the problem persists. Thinking it could be one of the input transistors, hoping not one of the ICs, as those look to be hard to get. Any thoughts on which transistors to try?