Proscan 50" PLDED5066A-E no backlights

[rustyweld]

Re: Proscan 50" PLDED5066A-E no backlights

Thank you Guys for your help.
I just ordered a Output Multipurpose Smart LED Lamp LCD TV Backlight Tester so I might be a little while before I get back at the tv. It seems to be a backlight problem so i'm stuck without a backlight tester.

[dick_barton]

Re: Proscan 50" PLDED5066A-E no backlights

I tried to turn the backlights down but the tv does not have a backlight setting.

This may be available from the service menu.

[budm]

Re: Proscan 50" PLDED5066A-E no backlights

https://www.badcaps.net/forum/attach...2&d=1448078807
Try turning down the Brightness, this set may use the Brightness setting to also controlling the Backlights level.
You can take the reading at the 'ADJ pin and see if that Voltage will go down when Brightness is turned down or not.

[attainteddragon]

Re: Proscan 50" PLDED5066A-E no backlights

you could also be looking at a connection issue in between the led strips. as they warm up, they are loosing connection somewhere. either way, you will need to look inside.

[Andrew F. Ali]

Re: Proscan 50" PLDED5066A-E no backlights

All the backlights light up so why would you say its a backlight problem? I just thought something other was shutting the light down. Could I check the leads to the lights with a multi meter and what shoud the readings be.

I was thinking that testing the backlight tester with a MM or LED tester does not supply the full current and that when they are in the circuit getting full current they trip out. We have seen this before.

[budwich]

Re: Proscan 50" PLDED5066A-E no backlights

what is your contrast setting? what is your brightness setting? what is your dynamic contrast setting?

you might have to get into the service menu to "attack" the backlight setting.

[rustyweld]

Re: Proscan 50" PLDED5066A-E no backlights

I tried to turn the backlights down but the tv does not have a backlight setting.

[rustyweld]

Re: Proscan 50" PLDED5066A-E no backlights

All the backlights light up so why would you say its a backlight problem? I just thought something other was shutting the light down. Could I check the leads to the lights with a multi meter and what shoud the readings be.

[Andrew F. Ali]

Re: Proscan 50" PLDED5066A-E no backlights

OK so you do have a LED backlight problem. Do as dick barton suggests and see if it will remain on longeror not shut off at all. If that works it still would not last too long and you would have to crack the panel open and replace those LED strips. If you figure out which LEDs are faulty DO NOT jump them wit wire as the rest of the strip will demand more current from the Driver and eventually burn out. In my experience the best repair is to change out all the strips with new ones as the older ones will fail in time and you will have to open her up again.

[dick_barton]

Re: Proscan 50" PLDED5066A-E no backlights

It's possibly a led fault. Turn the backlight down (not brightness) say to 60% and see if they stay on longer which they usually do when there's a led problem.

[rustyweld]

Re: Proscan 50" PLDED5066A-E no backlights

I have a proscan 50 inch tv (PLDED5066A-E) (S/N: A1305096070000235) that starts up with a great picture.Then lasts about one to two minutes and goes black. If i shine a flashlight on the screen I can see the menu and volume. If i shut it of then turn it back on it goes black after 20 to 30 seconds, then repeats the same again if i turn it of and on again. I have takened the tv apart and all the back lights work with it plugged in but go off after . I did not check the time as I was trying to see if all the lights where on but they didn't last very long. I was wondering if you could help as to diagnose the problem before I have to begin replacing parts.

[neilc6]

Re: Proscan 50" PLDED5066A-E no backlights

I replaced three LEDs on one strip on a similar model RCA RLDED5078A-D. Tv does not have a separate backlight adjustment, just brightness. Ran it for a couple of days and not super comfortable selling it though I did tell the buyer not to run it at full btightness.

[Glenn_Weile]

Re: Proscan 50" PLDED5066A-E no backlights

I've had success using the Digikey P/N: 1416-1222-1-ND (max 100 mA) to replace an open LED on a strip. I've also removed an LED from a strip and shorted it with a piece of wire wrap. (the customer was in a super rush for the repair and didn't want to wait for parts to come in)...

In doing so, I found I had to change the 510 K current sense resistor (0805 packaged device) coming off Pin 6 (I Sns input) to the BD92111F PMIC IC on the power supply board to a 470 K resistor...

I have a bad feeling that when these back light LED's start failing that sooner or later others will fail...

[techd]

Re: Proscan 50" PLDED5066A-E no backlights

I have the same Proscan 50" TV experiencing the same problem. How did you determine what LED part to purchase to replace the burnt ones on the light strips?

[budm]

Re: Proscan 50" PLDED5066A-E no backlights

Thanks for the follow-up, do not forget to turn down the backlights level in the user menu setup if you can.

[mnpdreed]

Re: Proscan 50" PLDED5066A-E no backlights

Decided to go ahead and complete the LED swaps. All of the bad ones were shorted. TV works perfect. Thanks everyone.

[mnpdreed]

Re: Proscan 50" PLDED5066A-E no backlights

Here is an update. I bought a rework air station. I was able to remove some LED s from and old strip and replace the bad ones. First on a success. I will try and get them all done this weekend and install back in TV to see if it works. Thanks again everyone for helping.

[mnpdreed]

Re: Proscan 50" PLDED5066A-E no backlights

Thank you I will try that this weekend

[paulstef]

Re: Proscan 50" PLDED5066A-E no backlights

1. remove the defective LED
2. remove excess solder with solder wick

3. Take a spare LED strip from another TV if you have one and cut out a piece of PCB containing a good LED one or two inches long
4. Glue that piece onto the strip to be repaired. Kapton tape and glue or double-sided tape.
5. connect the piece of PCB to the LED strip with wires.

DON'T bother trying to solder a LED onto the defective LED strip. It has big copper traces that serve as heatsink. Heating the LEDs to much during soldering will destroy them.

Don't know if you have backlights similar to these: https://www.youtube.com/watch?v=O2R3ZfCsYW4

[mnpdreed]

Re: Proscan 50" PLDED5066A-E no backlights

Thank you again for your time and patience. Is there a easy way to remove led from the strip?