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Equipment Repairs => LCD TV forum => Topic started by: Geoff S on May 05, 2018,12:16:04

Title: UE58J5200 Backlights failed and failed
Post by: Geoff S on May 05, 2018,12:16:04
 :41: Hi guys,

Has anyone had this before? UE58J5200 no backlights. When stripped to the leds I observed that a number of the leds had blown, ie burnt.

The customer said it crackled when it went off.

Ok so when I saw the damage I thought as a matter of caution to replace the PSU too. When the strips arrived I checked each and every one and they were all good...Changed all the led strips and PSU...Arcing immediately and promptly takes the leds out! I've cut my losses and the TV is scrap, but I'm just wondering if anyone may have any ideas as to the cause?

Geoff
Title: Re: UE58J5200 Backlights failed and failed
Post by: Turnip on May 05, 2018,13:13:49
Hi Geoff,

Had a couple of 32 inch sets where replaced Leds individually with some from Ebay for 42 inch sets (Ten for £7.50)

Some Leds were S/C and some O/C.

Only problem was getting the strips out 'till found had to push release toggles on connecting strip.

Before I realised, broke sockets and had to hard wire the lot - Sorted, but not the best way.

Admit not seen the 58 inch version, so possibly not useful - Chris.
Title: Re: UE58J5200 Backlights failed and failed
Post by: Geoff S on May 05, 2018,13:26:23
Cheers Chris,

Yes I've known those connections too. Because this set was such a horrible beast to work on I thought I'd take all the time and precautions I could but obviously something wasn't wanting to play the game.

The led strips all checked ok but I wonder if the PSU (ebay) may have had the same fault. "Removed from set with damaged screen"

We all know how it can be sometimes.......frustrating to say the least.

Beer therapy it is! :33:
Title: Re: UE58J5200 Backlights failed and failed
Post by: downunder on May 06, 2018,02:47:35

Been there-done that. Replaced power supply and the LEDs worked fine. Came back to bite me a few days later - no LEDs. Found they would come on if I put pressure on the centre joiner of the strips so I soldered links across each one. Then my problems started - it would kill LEDs so I ended up with 2 strips out. Struggled with the LED side connectors till I discovered you have to depress the detents at the rear of the connector. Kept killing LEDs as fast as I could replace them. Linked out all side connectors but still the slaughter went on. Couldn't now be sure if the power supply was OK.

Decided it wasn't worth all the hours I'd wasted on it, so advised the punter any repairs couldn't be guaranteed. He was OK with that.

Bruce
Title: Re: UE58J5200 Backlights failed and failed
Post by: Geoff S on May 06, 2018,07:51:38
Cheers Bruce,
I think that makes me feel a little better. I was going to do exactly what you mention. Not anymore!

Thanks
Geoff
Title: Re: UE58J5200 Backlights failed and failed
Post by: Turnip on May 06, 2018,11:34:02
Hi Bruce,

Glad not the only one to have to hard wire, not realising I had to push the toggles to get the strips out without breaking plastic.

Got one back after a day with another duff Led and dubious connections, so hard wired.

Next one was easy, as had got the idea at last. Tend to replace duff Leds individually as Ebay does 10 for £7.50 - Chris.
Title: Re: UE58J5200 Backlights failed and failed
Post by: Geoff S on May 09, 2018,10:32:22
Ok after a good bank holiday rest I've decided to bite the bullet and change duff led strips (ordered) and hard wire all connections.

I'll report how it goes.

Any precautionary advice gratefully  received.  :dubbio:

Geoff
Title: Re: UE58J5200 Backlights failed and failed
Post by: Geoff S on May 22, 2018,12:58:28
 :72: Yes! Great advise Bruce and Chris. Thanks guys
Title: Re: UE58J5200 Backlights failed and failed
Post by: downunder on May 23, 2018,03:30:01
Well, these sets know how to bamboozle one. A UA557100AM that works perfectly one day, then goes into a continuous boot loop the next. Even with main disconnected, the reboot continued and the backlights didn't automatically come on, so i thought power supply fault. With each reboot I could see a glimmer of light in each corner.

 Could it be the edge-lit strips? So I stripped the panel only to find that the LED tester lit up all LEDs in the many sectors of the strips, but running the TV only caused about 10 LEDs in each corner to function. All honky-dory. So it's back to the power supply where I've resoldered most joints, checked as much as I could and went over it with a magnifier. Drew a complete blank.

So now to hunt down another PSU, as they're NLA ex mfr.

Bruce.
Title: Re: UE58J5200 Backlights failed and failed
Post by: downunder on May 25, 2018,03:04:46

Well, it turns out that the power supply is at fault. Scored one from a mate, but comparisons between the two boards has me scratching my head. Still none the wiser.                                 Bruce
Title: Re: UE58J5200 Backlights failed and failed
Post by: downunder on May 27, 2018,19:37:57

Back to square one. After stuffing up the order of the diffuser sheets, something I'm always pedantic about. the set went back to LEDs flashing in the corners only. LEDs again check OK. Close to pulling the plug on this one. They must have an inherent PSU problem which I'm not yet privy to. Grrr.                               Bruce