TV LEDS come on a brief second, then off

[zomi]

Re: TV LEDS come on a brief second, then off

You can remove the strip by using hot air.
to warm it up so adhesive loosens.

You don't test the led from the back

[zomi]

Re: TV LEDS come on a brief second, then off

either side of the led
you probe there good led will light up with the meter in diode mode.

Please read through this now

https://www.badcaps.net/forum/showthread.php?t=25810

If you know some are bad anyway
search using the part number for strips

or u need a donor set..

or you need to solder the bad ones out and solder in new ones..
if that is something you can do...

if having done all that still an error then you may have a board out.
there is info one the board about using diodes in place of the leds to get the set going..
you will have to search though..

[kneeman]

Re: TV LEDS come on a brief second, then off

OK, I read that thread you posted Bud made, I watched a lot of videos, the last page or two there he had a video that showed to test the rear led driver board for volts to/from the 4 led strips. I tested at the wire connector and at the round brass spots he calls the return and both were at ~28v when the lights came on, then back to 0 when the lights went off.

As before ALL the leds now come on full brightness, no longer do I have a dark area in one strip. Also as before, pressing power once does nothing, then twice usually just make the leds dimmly lights, then the third time they fire up on full for a sec then shut down and will not turn on unless unplugged first. Sometimes it turns on with the second press.

There were also pins for LED On, GL Ctrl, Jig Ref, LD Err, Ground, Jig 12v Should I test these if so what should they be?

I then went to test each LED, I could not get my meter in diode mode to make each LED fire, I switched to Ohm and got ~8 across every LED on the tv.

I also tested the LED on at the secondary power supply out connector and also the in connector on the LED board and both showed ~3.3 when the LEDs came on for a second then they both went to zero as the light cut out.

I have no idea why all the LEDs work fine now but they do, they just all cut out after 1 second and you have to press power a couple times for them to come on that one time.

Now what?

[zomi]

Re: TV LEDS come on a brief second, then off

I posted before all details

now you have

the led driver board
the sub power supply board

one of these is causing issue maybe both..

they are all that is related to the led lighting

[kneeman]

Re: TV LEDS come on a brief second, then off

OK, I thought I ran all the tests you mentioned to narrow it down to one of those two boards. Sorry if I asked the same question twice.

I never saw what to do next to see how to narrow down which board might be the problem. Do you know? I have been watching youtube videos all day.

Sent you a pm about a different matter.

Thanks

[zomi]

Re: TV LEDS come on a brief second, then off

Regarding the led's maybe there was a loose connectionin wiring now with all fiddling its seated home now..

I would look for the secondary power supply board and the led driver board now..
if all leds are lighting up.. then one of those 2 should be the culprit.

Depending on how they are priced you could be served better buying bothat the same time from somewhere with a good returns policy even...

As you are in US try shopjimmy

[kneeman]

Re: TV LEDS come on a brief second, then off

Anyone recommend a good place besides ShopJimmy to get parts. They are out of both and all I read are bad reviews of everywhere else.

[kneeman]

Re: TV LEDS come on a brief second, then off

I know everyone is dying to get an update I am trying to source a Sony ST4055YL-S01

Guessing it is the LED board first.

Found one on Ebay from tv tear down went back an hour later to buy and it was sold. Only place I can find is shipping from Hong Kong, I'm still looking.

[zomi]

Re: TV LEDS come on a brief second, then off

Just be paitent and it will come up
Unless you need it up and running asap

[icethecold]

Re: TV LEDS come on a brief second, then off

I know everyone is dying to get an update I am trying to source a Sony ST4055YL-S01

Guessing it is the LED board first.

Found one on Ebay from tv tear down went back an hour later to buy and it was sold. Only place I can find is shipping from Hong Kong, I'm still looking.

Hey kneeman,

I might have bought the board you were looking at, turns out the board didn't fix my issue, as mentioned in my thread. Maybe we can arrange something? I'm not sure I have enough posts to PM anyone yet.

-Sean

[kneeman]

Re: TV LEDS come on a brief second, then off

Hey, just checked back here to update I am still looking for the board.

How many posts do we need to pm? I'll try and send you one.

What was the problem with your tv?

[kneeman]

Re: TV LEDS come on a brief second, then off

Just sent you a pm, I will check this thread tomorrow to and see if you got it.

[kneeman]

Re: TV LEDS come on a brief second, then off

You can read all my posts, but a quick review is my tv is completely apart. I tested each led on all 4 strips and they tested the same. I tested the 4 connectors on the LED board when I turn it on for 1 second before it goes out and they all read the same on the meter.

I do not know what it is, I was guessing LED board then secondary power supply, my 60" has two power supply boards.

The only tricky part with mine is when it first happened I had a dark sport on top when I turned it on, then it went off and I got the 4 red lights, after taking it apart I got the same results one time (about 1/3 of a strip would not light), then the next 20 tests I did all 4 LEDs lit 100% each time, no dark LEDs anymore.

The other thing odd is, when it as assembled I could turn it on with one press of the remote and it would power on and light for a second, then turn off and blink red until I unplugged it BUT now when I press the power button on the tv (while tv is still apart for repair) it does not turn on the first press of the button, nothing happens, when I press it again I see the LED strips very faintly glow for a milisecond then turn off, then when I press power a third time they ALL come on full bright a second then turn off.

I plug the tv in, wait one minute, press power, wait 3-5 seconds, press power again, wait 3-5 seconds, press power again. Once it came on the second time I pressed power.

[kneeman]

Re: TV LEDS come on a brief second, then off

UPDATE 10-5

Found a secondary power supply and it didn't fix it.
I tried pausing between power button presses longer and now it takes 2 times for the lights to flicker.

Press power nothing, press again quickly they dimly flicker once, press power again the come on 100% brightness one flicker.

Press power nothing, wait 10 seconds, press power they dimly flicker once then a second later flicker 100% bright then off.

Trying to find LD board next. If that doesn't work trying main board, if that doesn't work trying a hammer.

Unless anyone else has a suggestion.

[kneeman]

Re: TV LEDS come on a brief second, then off

Update 10-21

Tried a LD board and Secondary Power Supply board I found on Ebay, neither fixed it.

Should I try the main power supply board? Or try the next LD board that shows up?

I talked to another guy on here with similar problem and the first LD board he got on Ebay was a dud, the second one worked.

[kneeman]

Re: TV LEDS come on a brief second, then off

11-16-2015

Second LD Board came in. Same problem exists. So aggravating. Dunno if that is the problem now.

[ReeceyBurger123]

Re: TV LEDS come on a brief second, then off

STOP THROWING BOARDS AT IT THINKING IT WILL WORK ! You probably have a fault with the Led strips did you even check the return voltage from the Led strips, checked Bl on signal ?

[kneeman]

Re: TV LEDS come on a brief second, then off

STOP THROWING BOARDS AT IT THINKING IT WILL WORK ! You probably have a fault with the Led strips did you even check the return voltage from the Led strips, checked Bl on signal ?

Yes I tried grounding the backlight error wire. No help

Yes I checked the ohms in and out of each led light on the 4 strips. They were all the same

Yes I checked the voltage at the connection on the LD board where the power comes in from the power supply. All the inputs for power for the leds came back with the same volts when I turn the tv on and the leds light for a brief second.


If you want to read more details about the problem please read a previous post but in short, half a led strip didn't light at first, I took the tv apart expecting a bad led strip. That strip showed no brown or damaged leds. After apart I turned it on and now that one strip and all the strips turn on 100% bright but just for a second then it powers down.

Also the first time I press power no thing happens, I have to press it twice for the leds to light up a second.

Tried LD and secondary power supply boards so far.

[ReeceyBurger123]

Re: TV LEDS come on a brief second, then off

Have you tried checking the connection between the Led strips ?

[kneeman]

Re: TV LEDS come on a brief second, then off

Have you tried checking the connection between the Led strips ?

You mean at the connectors in my post #11 photos? No I have not tested anything there.

What should I test and what should I look for? For leds I tested each led on the strip that didn't fully light when the set was together and the measured the same on each.

Not apart they are come on. I thought maybe there was a loose wire and taking it all apart and moving it made it connect again, but sadly it still turns off after second but they all light up now.