Correct two different transistors .Ones a PNP and the other and NPN.Looks like each channel has two different resistors.
Correct two different transistors .Ones a PNP and the other and NPN.Looks like each channel has two different resistors.
I'd just replace 3 & 43 is bad, and No. 4 is good.
I assume by mica insulators you mean the very thin, plastic-looking "gaskets" between the transistors and the frame. If so, yes. They seem to be in great shape -- gunked up with white heat sink compound, but perfectly intact.
Did you go throught the idle/bias adjustments ? With the new outputs installed.UPDATE - November 2, 2018 * * * Parts arrived yesterday, and I installed them. Against your advice, Avionic, I went ahead and replaced all 4 output transistors (seemed most economical to order all four because shipping cost was the same). And then, the moment of truth. I powered up the unit, and guess what? Relay clicked on with a slight delay like normal. Phew! I think that was my problem. I played the receiver for about three hours last night -- varying the volume, but usually about middle range -- and no sign of any problem, My sweet CR-620 sound is back.
Look at the service manual and the silkscreening on the printed circuit board.Avionic, I did not go through the idle/bias adjustments after installing the new output transistors. Could you please tell me how to find the TP1, TP2, TP3 and TP4 test points on my board?
Sweet..Found them. TP1-TP2 came in at 14.1mV. TP3-TP4 came in at 12.2mV. With a little patience, I was able to get them both to hold at 8.0mV. I'm on a roll here! Thanks again for all of your help.