Good day folks. Time for me to tackle another Sony, TV which I absolutely hate to do because they're so needlessly complicated that....UGH....>_>
Anyway, this big bastard doesn't turn on: you plug it in, I can hear the relay click, it stays like that for a couple of seconds then the relay turns off and the red LED blinks 3 times....the service manual here says the 3 blink code means "abnormal panel voltage", but offers no clues as to how to troubleshoot that.
What I noticed on my own: if I jump the 3.3v stand-by pin to the "power on" pin, all the voltages come on at the output, so the PSU appears to be working. I can't quite understand the purpose of the relay though (page 35): I though it actually switches the mains on/off and I tried jumping that to 3.3v first, which indeed makes it click, but I still got no voltages at the output. Then I tried jumping just the "power on" pin and NOW I got the correct outputs, so why's that relay even there ?! Inrush limiter AFAI can tell: the main rectifier is in series with that 6.8 resistor (R6102) and when the relay is open it absorbs the initial rush current. When it closes, it bypasses that resistor and it sends full mains into the rectifier D6010 directly below it. I also see some sense lines across that resistor going to an optocoupler on the right...some current sensing perhaps ?
Now as I was messing around, plugging it in and unplugging it, it actually did fire up once, which would point towards a bad logic board or corrupted EEPROM, since the HDMI input doesn't work and it wouldn't turn on a second time after that, though it behaved differently this time: after turning it off with the button at the top, pressing it one more time to turn it back ok made the LED turn green, the relay closed again, but then it opened again WHILE the LED remained still green. It did this several times before finally going back to the 3 red blinks situation, so it's one sick TV the poor thing...where would we go from here ? Any ideas ?
Anyway, this big bastard doesn't turn on: you plug it in, I can hear the relay click, it stays like that for a couple of seconds then the relay turns off and the red LED blinks 3 times....the service manual here says the 3 blink code means "abnormal panel voltage", but offers no clues as to how to troubleshoot that.
What I noticed on my own: if I jump the 3.3v stand-by pin to the "power on" pin, all the voltages come on at the output, so the PSU appears to be working. I can't quite understand the purpose of the relay though (page 35): I though it actually switches the mains on/off and I tried jumping that to 3.3v first, which indeed makes it click, but I still got no voltages at the output. Then I tried jumping just the "power on" pin and NOW I got the correct outputs, so why's that relay even there ?! Inrush limiter AFAI can tell: the main rectifier is in series with that 6.8 resistor (R6102) and when the relay is open it absorbs the initial rush current. When it closes, it bypasses that resistor and it sends full mains into the rectifier D6010 directly below it. I also see some sense lines across that resistor going to an optocoupler on the right...some current sensing perhaps ?
Now as I was messing around, plugging it in and unplugging it, it actually did fire up once, which would point towards a bad logic board or corrupted EEPROM, since the HDMI input doesn't work and it wouldn't turn on a second time after that, though it behaved differently this time: after turning it off with the button at the top, pressing it one more time to turn it back ok made the LED turn green, the relay closed again, but then it opened again WHILE the LED remained still green. It did this several times before finally going back to the 3 red blinks situation, so it's one sick TV the poor thing...where would we go from here ? Any ideas ?