RCA LED50B45RQ LCD Flatpanel powers off right away

[SurrealMustard]

Of course! Why didn't I think of that sooner!

I just repaired this set. it was the LEDs shorted for me. disconnecting them i was able to power on just fine. when i opened it up i found LEDs on a few strings shorted.

Ah, I think you might be right. Can't believe I didn't think to try that earlier, but it does indeed power on and run just fine with the backlights disconnected. Looks like I'll be exploring that as the next plan of action with this thing.

[SurrealMustard]

Replaced bad backlights!

Backlights indeed. Replaced a couple strings, and this one is back in operation.

[DRLDallas]

Re: RCA LED50B45RQ LCD Flatpanel powers off right away

Didn't want to start a whole thread for what is hopefully a super easy question. I've got a RCA LED55C55R120Q TV and the backlights have recently stopped working. Everything I've seen here indicates it is most likely bad LED's in this model, but I was hoping to verify before opening the TV. I have a RE46HQ1640 power supply. When I turn on the TV the backlights fire for a split second, then go off. If I measure from LED+ (either one) I get a top voltage of about 130VDC as the backlights flash, then it rapidly decays to 0V over about 35 seconds. The LED- give me a reading of 48.6mv which could just be meter error. If I unplug the LED connector and power up the board, I get 230V on the LED+ terminals and the same 48mv on the LED-. I don't have the test equipment beyond a multimeter.

Is this what the power supply would act like if I had 'bad leds'?

Oh an occasionally the backlights will actually come on but rarely. I haven't been able to reproduce yet to test voltages in that state.

[dskall]

Re: RCA LED50B45RQ LCD Flatpanel powers off right away

I would say open circuit in led's. Bad led or bad connections