I picked this TV out of a trash pile. When I plug it in I can hear the relay on the power supply “click” almost immediately, and then 7 seconds later there is another “click” and the power/OPC LEDs start to flash: two pulses on the power LED, one on the OPC LED. I didn't notice any sign of life from the backlight, but more on that below.....
The service manual () says this is a “DET_10V error: UR10V or A9V is not applied”, but after checking several voltages I believe the power unit is tripping off due to an overload as soon as the backlight tries to come on; this kills the UR13V lines to the main board, which causes the error.
To test this theory I unplugged the master inverter and jumpered the STB and ERR pins together to prevent the main board from sensing a lamp error: in this configuration the power unit does not trip off. This arrangement also gave me time to confirm with a flashlight that there is an image on the screen.
I then re-connected the master inverter board but disconnected the slave inverter board. In this configuration the power unit also stays alive, and this was also the first time I had noticed any of the backlights briefly flickering on. After re-connecting the slave inverter and with the room darkened I could finally see that the backlights have actually been briefly lighting up all along, but it is much dimmer and has a much shorter duration than with the master inverter alone.
I have tried to troubleshoot the inverter boards using information from old threads, but I haven't made much progress. For example, I tried measuring the resistance of the secondaries on the transformers (as shown in post #29 in https://www.badcaps.net/forum/showthread.php?t=52087), but I get an open-circuit on all 10 transformers on the master. Could they all have failed? On the slave board I read 0-ohms on all of them, but as you can see from the close-up photo this is to be expected because they are joined by a trace (the red lines mark the legs of the transformer). The part number on the transformers is 2874029300; I haven't been able to find any information on them, other than places that want to sell me a new one.
If anyone has any ideas on how I might proceed, I would appreciate any suggestions.
The service manual () says this is a “DET_10V error: UR10V or A9V is not applied”, but after checking several voltages I believe the power unit is tripping off due to an overload as soon as the backlight tries to come on; this kills the UR13V lines to the main board, which causes the error.
To test this theory I unplugged the master inverter and jumpered the STB and ERR pins together to prevent the main board from sensing a lamp error: in this configuration the power unit does not trip off. This arrangement also gave me time to confirm with a flashlight that there is an image on the screen.
I then re-connected the master inverter board but disconnected the slave inverter board. In this configuration the power unit also stays alive, and this was also the first time I had noticed any of the backlights briefly flickering on. After re-connecting the slave inverter and with the room darkened I could finally see that the backlights have actually been briefly lighting up all along, but it is much dimmer and has a much shorter duration than with the master inverter alone.
I have tried to troubleshoot the inverter boards using information from old threads, but I haven't made much progress. For example, I tried measuring the resistance of the secondaries on the transformers (as shown in post #29 in https://www.badcaps.net/forum/showthread.php?t=52087), but I get an open-circuit on all 10 transformers on the master. Could they all have failed? On the slave board I read 0-ohms on all of them, but as you can see from the close-up photo this is to be expected because they are joined by a trace (the red lines mark the legs of the transformer). The part number on the transformers is 2874029300; I haven't been able to find any information on them, other than places that want to sell me a new one.
If anyone has any ideas on how I might proceed, I would appreciate any suggestions.
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