55" RCA LED55G55R120Q no backlights

[Gadjet]

55" RCA LED55G55R120Q no backlights

I have tested the backlights with my LED tester, LEDs are working. Tester shows 146 on both leads to lights. No voltage coming from the LED connector on the power supply. What would cause the power supply to not output voltage to the LEDs connector?

All other voltages on the power supply are correct same on a second power supply I just got in from shop jimmy. New power supply is an Rev. 1 board, old board is Rev. 5 not sure if that makes a difference results are the same. Can see the picture with a flashlight and I get audio.

I use to be able to get the lights to come back on by unplugging the TV for a bit and holding the power button, it's not working anymore since I removed the power supply and mainboard. The old power supply is the one not attached.

[Gadjet]

Re: 55" RCA LED55G55R120Q no backlights

I made a mistake plugging the wires back in so now I am getting the backlights to come on again when unplugging from the outlet and back again. As long as I don't try to change the input I'm using like HDMI 1 or something the tv seems to run flawlessly. After an hour or so changing the input will cause the backlight to go out. Also when I attempt to turn off the tv after this has happened the red standby light doesn't come on. The voltage shows that the tv has powered down. Anyone know if the mainboard has an inverter controller on it?

[CapLeaker]

Re: 55" RCA LED55G55R120Q no backlights

To make this short:
RCA sucks so bad, I just junk them. Next thing is that there are guaranteed like 6 different versions of that TV. So the model number alone doesn't cut it. That big main IC on the main board controls PSon and BLon. You have to find the PSon and BLon pins on the PSU and see if you loose BLon or not. Its on that ribbon cable that goes from the PSU to the main board. I wouldn't rule out the EEPROM on the main board at this point, but there could be also something wrong with the MSD IC too. Sorry for the rant, but those things are just terrible.

[Gadjet]

Re: 55" RCA LED55G55R120Q no backlights

Thanks for the reply, I had ordered a mainboard it got in yesterday, I've run the tv all day changing inputs even cut it off and on a few times. So this morning I changed inputs and turned it off and on. Decided to do it one more time just for the hell of it and the backlights didn't come on. Of course unplugging it and back allows me to turn it back on. So the new mainboard allows it to stay on for more hours than the original. I also tried it with the old power supply and new mainboard the lights will go out with it just sitting on for a hour or so. Could the FRC Board have anything to do with it?

[tvtimmy]

Re: 55" RCA LED55G55R120Q no backlights

RCA junk,crap,cheap pieces of shit,allways kick in the panel.......+100000000

[Gadjet]

Re: 55" RCA LED55G55R120Q no backlights

Ok, latest update, I understand how everyone feels about the company but it's a clients tv so it would be bad customer service for me to kick the panel in...lol. I installed a new FRC board a day ago and the tv ran close to an entire day turning it off and on, and changing inputs so everything seemed fine but I still didn't trust it. Turned it off and on a few times this morning and Bam!!! The lights flashed and that was it, the sound is always there and as I've stated if I unplug it then plug it back in it will come back on without any problem. The lights have never gone out without me using the power button or changing to another input.

Where could it be losing power?
Could something be overheating?
Is there a way it could be the backlights even though they are working?
Also is there any way it could be the T-con? It's the only board I haven't changed.

[CapLeaker]

Re: 55" RCA LED55G55R120Q no backlights

I am a bit confused here. Do you have no backlights when the screen goes of (audio is still playing), or are the backlights on and have a black screen?
Can we see your Main and TCon?

[budm]

Re: 55" RCA LED55G55R120Q no backlights

"The lights have never gone out without me using the power button or changing to another input." Which lights?

[Gadjet]

Re: 55" RCA LED55G55R120Q no backlights

@capleaker

The TV works as it should, backlights are on everything works. After maybe an hour or more that's were the problem comes in. If I turn the tv off and back on the backlights might come on or they might not. If they do not I have to unplug the tv and hold the power button. when I plug it back up the tv will power up again and work as it should for as long as I leave it on. I've had it running a whole day no problem. There is a random issue with the backlights losing power somehow. The picture is still there if I take a flashlight to it or use my led tester to power the backlights. The sound is still there as well.

[Gadjet]

Re: 55" RCA LED55G55R120Q no backlights

@budm I was speaking of the backlights, after about 1-3 hours

[budm]

Re: 55" RCA LED55G55R120Q no backlights

https://www.badcaps.net/forum/attach...1&d=1511592650
Take the DC Voltage on that white connector (it has pin labels for each pin so make sure to write down the pin name and follow by the measured Voltage reading) that goes to the main board when the TV stops working. At this point it looks to be main board problem.

[Gadjet]

Re: 55" RCA LED55G55R120Q no backlights

@budm...I've checked all the voltages they are the same when the backlights are working and not working, aside from the fact that the backlight connector on the power supply is no longer getting any voltage when the backlights go out. The rev. on the mainboard I ordered is older it's an (a1) and the original is an (a2). I've even tried swapping the EEPROMs. The same thing happens.

[Chinder]

Re: 55" RCA LED55G55R120Q no backlights

@Gadjet Did you ever resolve your backlight issue? I'm having the same issue with this same TV I'm working on. Replaced PS board and still have no backlights. There's an image on the screen but no backlights. I obviously checked the backlights with a tester and checked the voltage of the power supply. If you found a solution let me know. Thanks

[R_J]

Re: 55" RCA LED55G55R120Q no backlights

@Gadjet Did you ever resolve your backlight issue? I'm having the same issue with this same TV I'm working on. Replaced PS board and still have no backlights. There's an image on the screen but no backlights. I obviously checked the backlights with a tester and checked the voltage of the power supply. If you found a solution let me know. Thanks

He is likely long gone, this post is 5 years old.
If you checked the led voltage supplied by the power supply, what was it? led testers do not always detect a bad led in the string, You very likely have a bad led in the panel.

[neilc6]

Re: 55" RCA LED55G55R120Q no backlights

Every RCA LED TV I've encountered had bad backlights if it turned on with no backlight or flash of backlights. Impossible to get new LED strips for them so I repair the individual LEDs and turn down the backlight level as low as possible in the service menu. Menu-1-1-4-7 or source-2-5-8-0 under panel settings. I've encountered models where lowering the backlight didn't save or I couldn't adjust it with the remote cursor buttons. Some do have energy savings picture mode which run the backlight a little lower than max.

If TV doesn't turn on and has standby light, likely a bad EEPROM. Test by freezing the EEPROM with an upside down can of duster before plugging in.

[Tv Terminator]

Re: 55" RCA LED55G55R120Q no backlights

So long story short I have the 65 inch version of this TV, when I first diagnosed it. I did so without taking anything apart. I had image no lights so automatically assumed it's back lights. I bought the lights took it apart tested the lights to see which strip or led was bad. Literally all strips were good, but still didn't power on when the TV was turned on. Being the optimistic loser I am I replaced all the LEDs and that did it for me. Not sure wth the issue was but the TV is fully functional and I regret ever fixing it because the TV is not the greatest quality not to mention its so bulky.

[nomoresonys]

Re: 55" RCA LED55G55R120Q no backlights

Yep, rca's are junk, have yet to even see one with a decent quality picture since flat panels came out let alone all the other problems they have. You don't even have to get close enough to read the brand to tell which are the rca's at walmart, they're the ones with the shittiest picture from far or near.

[RinusB]

Re: 55" RCA LED55G55R120Q no backlights

LED backlights are current controlled so backlight testers may read them as "good" or shorted. The detection circuit can trigger an abnormal high or low current even when everything seems normal.
My RCA RTU6049 backlights tested fine but when operating (Minuts only) the voltage to the backlights was all over the place.
I had seen the bouncing voltages before so looking at the backlights with the screen removed showed one LED occasionally flickering. Using my newer LED tester I used the low current setting and that one LED tried to light up but failed while all others were glowing but dimly.
Protection circuits are designed by engineers and obviously they work very well. A bit wider tolerance would work to keep them working similar to a slow blow fuse.
But having said that, many of the Pioneer Receivers I fixed fail early due to lack of a simple heatsink on 5 of the ICs on the HDMI board. They never acknowledged they even had a problem.
My TV also had more versions. I am sure they are made by the lowest bidder and not to fix any problems.

[RinusB]

Re: 55" RCA LED55G55R120Q no backlights

LED backlights are current controlled so backlight testers may read them as "good" or shorted. The detection circuit can trigger an abnormal high or low current even when everything seems normal.
My RCA RTU6049 backlights tested fine but when operating (Minuts only) the voltage to the backlights was all over the place.
I had seen the bouncing voltages before so looking at the backlights with the screen removed showed one LED occasionally flickering. Using my newer LED tester I used the low current setting and that one LED tried to light up but failed while all others were glowing but dimly.
Protection circuits are designed by engineers and obviously they work very well. A bit wider tolerance would work to keep them working similar to a slow blow fuse.
But having said that, many of the Pioneer Receivers I fixed fail early due to lack of a simple heatsink on 5 of the ICs on the HDMI board. They never acknowledged they even had a problem.
My TV also had more versions. I am sure they are made by the lowest bidder and not to fix any problems.

I have a newer LED backlight tester that checks current also. I will test the backlight current to see if the lights (current) fluctuate after warming up.