My parents gave me a Sony KDL-42ex440 TV to repair it for them.
When I plug the TV in mains, the power LED (green) turns on immediately. After few seconds the back-light flashes for a moment and immediately back-light goes off.
After about 5 seconds TV shuts down (no LED is on). The slight pop sound can be heard from speakers while the TV switches off.
If I want to turn the TV on I must unplug it from mains and plug it again.
I have tried and I can confirm that panel is showing picture after the back-light flash (while the back-light is not on) - I pointed strong light from the front of the screen in order to see the image on screen.
I can see "Sony logo" shown in the middle of the panel and after that "input HDMI 2" in top-left position of the panel.
It seems like T-CON board is OK.
I tried unplugging LDVS cable from the main board, TV shuts off again.
TV can be switched into stand-by mode using IR remote and also using controls on TV (this can be done before the TV goes OFF).
TV goes to stand-by and it can stay that way until I turn it on using IR remote or controls on TV.
After that the complete sequence I explained above repeats until the TV shuts down.
I updated firmware using the USB flash procedure. I assume update finishes successfully but the TV behaves the same.
I tried unplugging both back-light power connectors - TV shuts down as described above.
Than I tried plugging in only the left back-light power connector, back-light flashes and TV turns off.
After that I plugged in only the right back-light power connector, back-light doesn't flash and TV turns off.
I measured voltage on both back-light power connectors and after the back-light flash voltege on both connectors is 200V DC.
The back-light flash period is extremely short so I am not able to measure the voltage.
It looks like the right LED strip is broken but I believe that this would not cause the TV to shut off completely.
I have measured 3.3V and 12V on PSU.
All capacitors look OK to me.
I could not find the schematics for the PSU GL10 - so I don't know if 200V for back-light is OK.
Any help is appreciated. Thank you.
When I plug the TV in mains, the power LED (green) turns on immediately. After few seconds the back-light flashes for a moment and immediately back-light goes off.
After about 5 seconds TV shuts down (no LED is on). The slight pop sound can be heard from speakers while the TV switches off.
If I want to turn the TV on I must unplug it from mains and plug it again.
I have tried and I can confirm that panel is showing picture after the back-light flash (while the back-light is not on) - I pointed strong light from the front of the screen in order to see the image on screen.
I can see "Sony logo" shown in the middle of the panel and after that "input HDMI 2" in top-left position of the panel.
It seems like T-CON board is OK.
I tried unplugging LDVS cable from the main board, TV shuts off again.
TV can be switched into stand-by mode using IR remote and also using controls on TV (this can be done before the TV goes OFF).
TV goes to stand-by and it can stay that way until I turn it on using IR remote or controls on TV.
After that the complete sequence I explained above repeats until the TV shuts down.
I updated firmware using the USB flash procedure. I assume update finishes successfully but the TV behaves the same.
I tried unplugging both back-light power connectors - TV shuts down as described above.
Than I tried plugging in only the left back-light power connector, back-light flashes and TV turns off.
After that I plugged in only the right back-light power connector, back-light doesn't flash and TV turns off.
I measured voltage on both back-light power connectors and after the back-light flash voltege on both connectors is 200V DC.
The back-light flash period is extremely short so I am not able to measure the voltage.
It looks like the right LED strip is broken but I believe that this would not cause the TV to shut off completely.
I have measured 3.3V and 12V on PSU.
All capacitors look OK to me.
I could not find the schematics for the PSU GL10 - so I don't know if 200V for back-light is OK.
Any help is appreciated. Thank you.
Comment