I soldered out one pin, but it seemed to work fine. Next, I checked the double diode CR5/6 set in the heatsink. I did not solder them out before measuring, as I thought this would be ok (or am I wrong here?). Then I replaced the other capacitors, marked in yellow: To do so, I soldered out 2 pins of all the transistors I could find and measured them. I thought that those were broken for sure, but when I tested the 2N2055 (using the diode test on my multimeter), they seemed to be ok.Īfter this, I tried to check all the other parts on the PCB (as suggested in this thread). I already read in this thread that these are not the best choice, so I ordered MJ15015 (but did not install them yet). Next, I soldered out the power transistors, those were 2N3055. I was unable to find the specified 5000uf/63V types, so I used 4700uf/63V. I tried to measure the replacements, and my multimeter says they are about 4500uf each. So I started by replacing the diodes CR12-15 with the specified 6A types, and I put in new capacitors, as I did not really trust the replacements. Also, C13 and C14 had obviously been replaced - there were new capacitors, but they were not soldered onto the board, but connected to the board with pieces of cable (the pins of the new parts did not fit the holes on the PCB). The diodes CR12, 13, 14 and 15 had been replaced, but with 3A types instead of 6A, as specified in the schematic. When I opened the amp, it was clear that somebody had been working on the power amp PCB already. It seems to be a little different from what there actually is on my power amp PCB, for example the two fuses for the power supply for the front panel are missing in this file, but I guess that it is close enough. I replaced it with same rating and voltage, switched on, and the red LED on the front panel came on for about 2 seconds before the new fuse broke again. When I got the amp, the main fuse was broken.
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