A set I found in SoCal I bought to flip. It was broke and in crusty shape. It had been repaired once before but this time both amps were railed due to a bad PS. I got that sorted and rebuilt the amps with new silicon and caps. The left amp would not show any idle adjustment. Checking everything again I looked at the Bourns trimmer values as I did have some base voltage at the pre drivers and they responded to the trimmer movement. The bad amp was only half the 1.5v pre driver base voltage of the good amp. Half? WTHeck I looked at the traces and ohm'ed out each trace (Which doesn't take as long as some would think). They all checked good. If I cranked the idle trimmer full CW I could get a mV. So I went to the trusty STV and found this: Its a STV-4H (Should read 1.835v) Not that this failure is really rare but it is the first time I saw one reading almost half of the correct value.