RCA 42" RLDEDV3988-a flickering video

[tech2014]

The video flickers. Cannot find any service manual or schematic for this tv. It is a tv/dvd combo. Here are some pics of the unit, assuming the small boards are the buffer. Here are some pics of the boards. Not much too see. Do the boards with the ribbon cables control the video, or is there a power supply or backlight issue.

[tech2014]

Re: RCA 42" RLDEDV3988-a flickering video

Can someone tell me what could cause this issue?

[tech2014]

Re: RCA 42" RLDEDV3988-a flickering video

obviously its not just me, nobody has a sniff about this tv lol.

[Caleb]

Re: RCA 42" RLDEDV3988-a flickering video

If you put it on a blue screen does it still flicker? Need to see if its the image or the backlights.

[garfield-cat]

Re: RCA 42" RLDEDV3988-a flickering video

I am having the same issue with mine .. hope we can get this figured out

[garfield-cat]

Re: RCA 42" RLDEDV3988-a flickering video

Mine flickers about once per second regardless of what is on the screen. I can still see the image in the background when it flickers so I am assuming it has something to do with the back lighting

[tech2014]

Re: RCA 42" RLDEDV3988-a flickering video

I can see the backlight LEDs flashing. I thought it could be an inverter board but can't find one. How do I get a blue screen? Is it a test screen?

I also cannot find a schematic or service manual for this tv.

The customer told me she has another RCA tv(the exact same model) and it also flickers. This tv is in warranty so she is going to send it for repair. I told her to let me know what they find so I can fix. I will let you know garfield-cat. Btw, hows the weather out there in NS?

[Caleb]

Re: RCA 42" RLDEDV3988-a flickering video

Usually if you set it on a source with no signal you will get a solid blue screen. But it sounds like it is a common problem in the back light of this model to have 3 with similar troubles in quick succession. If you get into the settings you may be able to find a setting labelled Energy Saving or something along those lines. Turn it off and see if it quits pulsing. I think it may be using pulse width modulation to keep down the power usage but it is set at too low of a frequency.

[tech2014]

Re: RCA 42" RLDEDV3988-a flickering video

I checked the voltages in the inverter cct and used alligator clips to test. When I am taking voltage the backlight comes on and stays on. I found the voltages should be about 30V but it was moving around between 28-61 volts. Could this be a cap issue or semiconductor.

[Caleb]

Re: RCA 42" RLDEDV3988-a flickering video

if the only thing you did was clip in your test leads it sounds like something is loose. However if the voltage is still pulsing while your clipped in look at the power supply, I suppose it could be faulty caps. BTW this tv wont have an inverter circuit as it is using leds, just power to feed the strings of leds and some kind of feed back for fault protection.

[ReeceyBurger123]

Re: RCA 42" RLDEDV3988-a flickering video

I checked the voltages in the inverter cct and used alligator clips to test. When I am taking voltage the backlight comes on and stays on. I found the voltages should be about 30V but it was moving around between 28-61 volts. Could this be a cap issue or semiconductor.

Hello, firstly check the voltages coming out of the main psu and check that they are in spec.
I have seen a tv almost exactly like this but with a different inverter that had the same problem my mate ended up replacing the main board and the psu as the main board was generally glitchy and the psu was out putting bad voltage.

[tech2014]

Re: RCA 42" RLDEDV3988-a flickering video

I fixed the TV. I was doing voltage measurement on the secondary side inverter section and found an open surface mount resistor. Replaced the part and problem solved. Thanks for the input guys.

[garfield-cat]

Re: RCA 42" RLDEDV3988-a flickering video

Weather here has been nice most of the summer.
Tech2014 .. can you lead me in the direction of where you found the open resister so I can see if it is the same issue I am having?
what size resister is it?

Thanks

[Caleb]

Re: RCA 42" RLDEDV3988-a flickering video

Glad you found it! Can you post the location and part number so people reading this thread later can find it easily.

[salmo]

Re: RCA 42" RLDEDV3988-a flickering video

I fixed the TV. I was doing voltage measurement on the secondary side inverter section and found an open surface mount resistor. Replaced the part and problem solved. Thanks for the input guys.

If you have the skill to find and replace a surface mount part you are way beyond me. Wish I knew how.

[kidd]

Re: RCA 42" RLDEDV3988-a flickering video

Hi I also have the same TV model, and need information on how to find the problem (resister) or where to look ???

[Agent24]

Re: RCA 42" RLDEDV3988-a flickering video

He seems to have said that he found the open resistor while checking voltages in the secondary side of the inverter section...

Maybe something to do with lamp current sensing\feedback etc. Check maybe the lamp feedback circuit.

If it's open circuit it might be visibly bad, if you're lucky.

[guy654321]

Re: RCA 42" RLDEDV3988-a flickering video

having same problem but tv is black with only flickers of the image ???? Tech2014 ????

[bufferb]

Re: RCA 42" RLDEDV3988-a flickering video

I fixed the TV. I was doing voltage measurement on the secondary side inverter section and found an open surface mount resistor. Replaced the part and problem solved. Thanks for the input guys.

SO you wont tell us what RESISTOR,SO I & 100 more people are spending
2 hrs trying to find this resistor.with no luck.IS this april fool's day or what.
NOT very HAPPY.

[bufferb]

Re: RCA 42" RLDEDV3988-a flickering video

Weather here has been nice most of the summer.
Tech2014 .. can you lead me in the direction of where you found the open resister so I can see if it is the same issue I am having?
what size resister is it?

Thanks

WHY hasent this repair been told to members.YOU found a resistor what RESISTOR & WERE.