brit01 wrote:Also to add to the above I'm getting only about 1.85 mv on the left channel idle.
sorry, that should be 2.5mV +/- 0.5 so it was probably good. Unfortunately those pots are not very smooth in their adjustment reaction, so it's probably out now. Add to that the fact that it didn't change and hmmmmmm.....
.....Can I adjust this to 2.5 mV before knowing the right idle? Well I tried a quarter both ways and no effect on the mV setting
1/4 turn in either direction is substantial. if it made no difference, either you're on the wrong test point or the bias circuit is fubar. To check:
1. make note of the pot position
2. for the left channel IIRC counterclockwise is less and clockwise is more (reversed for right channel)
3. BRIEFLY, and with your ear to the transformer (uh,,,,,magnetic field coil) crank the pot to max and back.
4. if the mag coil starts humming you're on the wrong test point and it IS increasing the bias.
5. if the mag coil doesn't get louder the bias circuit has a problem
brit01 wrote:......Also I'm getting about 310 mV from the left speaker terminals! nothing from the right terminals (the right is dead silent when I power up, the left just a little bump)
is that AC or DC? either way it shouldn't be there. It's not destructively bad, but it's also not right.