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Panasonic TH-L50B6A
downunder:
Hi Dan.
I have uploaded the service manual to the download section. Backlight failure seems common on this model - uses a LG panel - but this invariably activates a error code of 1.
Check these voltages on the LD Board for stability. At connector LD1, BL-ON at pin2 and 24V supply at pins 8,9,10. At LD3 (output),
pins 1 and 5 are the LED drive voltages.
A pity brooksy didn't follow up but I have to say my gut feeling is an iffey panel (LEDs). Bruce
danyelgeelong:
Hi Bruce.
Thanks for your prompt reply and also for uploading the service manual again.
I will do as you have mentioned and report back with my findings, only due to work commitments, I wont get a chance to do anything until midweek :(
Regards!
danyelgeelong:
OK so it wasnt easy testing these voltages on my own because once the TV throws the error (green light goes out, red starts flashing) I have to put the tester down to unplug and plug back in the TV mains every 5 seconds or so. Ive tested the at connector LD1, BL-ON at pin2 (fluctuating between 0 to 3.2V) and 24V supply at pins 8,9,10 (all have 24V +or- <0.5V) And at LD3 (output), pin 1 (fluctuating between 9 to 14V) and pin 5 (nothing at all).
I've been searching for an unicorns err LD Boards, found one, second hand, selling for more than Id like to spend on S/H. So hoping it may be something else causing this problem.
Next step?, disconnect the BL-ON line, or cut it, and connect it via a 100 ohm resistor to the STB-5V (or 3V3) as a substitute for the BL-ON voltage. Only problem is in the schematics I cannot tell which is the STB-5V (3V3) :(
downunder:
What about using an external power supply......a couple of 1.5V batteries perhaps. The output at LD3 is definitely screwed up.
BookWormStud:
--- Quote from: downunder on July 11, 2015,03:53:00 ---
Problem may well be A-Board if BL-ON is all over the shop, as that's where the BL-ON is generated.
Can you disconnect the BL-ON line, or cut it, and connect it via a 100 ohm resistor to the STB-5V (or 3V3) as a substitute for the BL-ON voltage. If the backlights come on without flickering, then you'll know the A board is the offender.
You are correct in that the 16V to the LD board is not used.
Bruce
--- End quote ---
Hi
can you please elaborate this in easy words please.
thanks
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