I thought the f5 boards had some shorts with the heatsinks so I removed the boards from the heatsinks and in 3 seconds Q4 smoked. Now only one channel is connected and it doesn't hum. But I think it's because one channel is disconnected. Can I make any kind of test now with only one channel or I should wait to repair the other channel?
I've changed the q4 but in few second I've seen smoke again, but I didn't understand where. I've seen R11 is brown but the resistance is the same as the other working board. Now after fuse blowing I've reattached my bulb tester and of course lights on. After turning full ccw the pots the light is off but I still have full rali voltage on output
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+V I assume; reflow the solder joints on Q4 with fresh solder, they look like dry joints, then begin the bias process from the start, hopefully Q3 survived.
Can the other transistors Q1 Q2 Q5 Q6 have fault?
Just 3 seconds without heatsinks...
Just 3 seconds without heatsinks...
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Am I right in seeing a very bad if any ground connection (at mains socket) and no connection to the chassis?
earth=black wire in the third pin in pem. It's soldered
Under the pem there's a cap between chassis, gnd and earth.
My photo doesn't apply - I'm wired for 120V AC, he's in a 240V country. His primaries must be in series, ours in parallel. 🙂
