bmanone
Active Member
I picked up Yamaha M-80 off Craigslist a couple of weeks ago in non-working condition. Got it on the workbench and found:
Thanks for reading and for any suggestions.
- A blown 10amp fuse,
- Transistor (TR114), resistor (470 ohm), capacitor (C160) and diode (D120) all gummed up with glue (replaced these parts)
- Output transistor (TR137) shorted replaced all the output transistors in that channel (TR131, TR133, TR135 and TR135)
- Driver transistor TR119 bad, so I replaced these transistors (and complementary PNPs) in both channels (TR119, TR120, TR125, and TR126)
- Also replace all the electrolytic capacitors (except the 4 large filter caps on the power supply)
- Replace two 0.047uf, 400v capacitors (C324 and C331) on the Power 1 board (caps were out of spec – measured 0.020uf) with 0.050uf, 630v capacitors.
Thanks for reading and for any suggestions.