FireGuruMN
Active Member
I fired up (literally) my AU-X1 yesterday because I was feeling nostalgic. One channel was silent. So I went around to the back and found that on of the RCA connectors was loose. When I plugged it in I heard a distressing "sizzle" from deep inside the amplifier. The power/protection light started flashing. I turned it off. When I opened it up to investigate I found that two resistors on one of the driver boards were destroyed. See pictures. So I unsoldered the leads going to that board and pulled out the heat sink. I found R41 (47ohm, 1 watt) blown in half and R39 (560 ohm 1/2 watt) melted. I also noticed that R36 was modified into two resistors at some point in the amplifier's life. But that does not seem to be a problem. It would also seem that someone upgraded all the R41's to 1 watt from the original 1/2 watt values.
My question is: Do I just replace the two resistors and put it all back together or are the resistors indicative of a larger problem like a failed transistor or such? It would appear that transistors on this driver board have been replace previously in this unit since the colors do not match. I did not check part numbers on them. Is there an easy test for a transistor? Forgive my ignorance.
Also, can I "just" Deoxit (F5 for faders) the volume knob and two level knobs to get rid of scratchy noise or will that destroy what appears to be a very sophisticated potentiometer?
Anything else I should do while it is on the operating table?
Serial number 239050093 if that is relevant.
My question is: Do I just replace the two resistors and put it all back together or are the resistors indicative of a larger problem like a failed transistor or such? It would appear that transistors on this driver board have been replace previously in this unit since the colors do not match. I did not check part numbers on them. Is there an easy test for a transistor? Forgive my ignorance.
Also, can I "just" Deoxit (F5 for faders) the volume knob and two level knobs to get rid of scratchy noise or will that destroy what appears to be a very sophisticated potentiometer?
Anything else I should do while it is on the operating table?
Serial number 239050093 if that is relevant.