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Old 01-21-2014, 01:06 AM   #1
freakaftr8
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Default Another sony led back lighting problem.

Kdl 55hx729 picked it up tonight with a 5 blink code. Repaired the bad ribbon LVDS cable and found that the LED's on a quarter the bottom go out after 2 seconds of being on. Of course this throw the for blink balancer issue. I'm thinking it is a certain led problem due to the fact that they do work upon first startup. after testing the balancer board I am pretty certain that led is overheating and shutting down immediately incense the LED's are wired in series one goes out the rest go out. I think I'm just going to pull the panel in check the LED strip one by one. Has anybody had any success rate at this problem.?

I know there has been a few other members on the forum having the same issues with their LED Sony backlit TV. Has anyone successfully repaired this yet?

http://i845.photobucket.com/albums/a...ps42cfe091.jpg

http://i845.photobucket.com/albums/a...ps4b65285e.jpg

Last edited by freakaftr8; 01-21-2014 at 01:11 AM..
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Old 01-21-2014, 03:06 AM   #2
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Default Re: Another sony led back lighting problem.

Never mind. I found a hole burned in one of the balancer Ic's. either going to try to rebuild the balancer board or replace it not sure yet it appears that this board is hard to find.

on another note I did learn something new that might come valuable to other members. If you disconnect the LVDS cable from the tcon board then as you are plugging in the TV hold the power button at the same time you will get a momentary white screen and it will light up all LEDs for approximately 1.5 seconds and you can do this again and again and you will be able to see if you have any bad LED's behind the screen. I came across this on accident but it appears that it is a useful tool in trying to find a bad led.

Last edited by freakaftr8; 01-21-2014 at 03:08 AM..
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Old 01-21-2014, 05:17 AM   #3
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Default Re: Another sony led back lighting problem.

only trouble is,an lcd panel has many diffuser sheets in them,trying to define a faulty led can be hard,with ccfl,you have more of a chance,as if one fails it tends to give a uniform shadow,but the feed back circuit will prob only give you around 2 secs to see before it shuts the inverter down.
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fixed so far...376 lg lcd tv's,24 onn tv;s,24 panasonic lcd,16 jvc lcd,12 marshall jcm800 amps,refurb of various disco equipment lighting,old style disco decks ,and a flymo!

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please let us know if everything works ok if your tv gets fixed, as it will be and aid for anyone else having the same problem and wishing to fix it.it would save people clogging up this site with topics that are duplicated,and can be found easily using the search function.,and taking up valuable space.enjoy your fixed tv!,hopefully!
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Old 01-21-2014, 11:02 AM   #4
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Default Re: Another sony led back lighting problem.

Which one is the balancer?
To me, it looks like one of the LED driver ICs must be bad. I had pretty much the same thing, but half of them didn't light up. I had two ICs out. Mine it was an 46NX720 model.
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Old 01-21-2014, 11:07 AM   #5
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Talking Re: Another sony led back lighting problem.

Quote:
Originally Posted by multimeter View Post
only trouble is,an lcd panel has many diffuser sheets in them,trying to define a faulty led can be hard,with ccfl,you have more of a chance,as if one fails it tends to give a uniform shadow,but the feed back circuit will prob only give you around 2 secs to see before it shuts the inverter down.
THis is very true. Best way is usually the hardest by removing the panel..then doing g my power up trick..
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Old 01-21-2014, 11:38 AM   #6
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Default Re: Another sony led back lighting problem.

Actually I think I'm using the wrong terminology. I would assume the balancer is connected to the power supply. The local dimming driver is connected to the t-con board that's unit that's bad. Looks like I can't locate the IC's as they don't seem to sell em in the US and I'm not going to order and quantities of China so I just found the board for $70 so I ordered it we'll see how this turns out
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Old 01-21-2014, 02:21 PM   #7
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Default Re: Another sony led back lighting problem.

The board, above the T-con with metal cover on it, right? I believe that is called LED driver board.
Here is mine:
http://www.shopjimmy.com/sony-st4055yl-s01-yl-board.htm
That I had to replace myself. I would have ordered the ICs from China, but I was anxious to see it running, so I have just did as you did, and got another board for $58.
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Old 01-21-2014, 03:57 PM   #8
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Default Re: Another sony led back lighting problem.

Yes that's the board. Agreed it would be more cost effective to replace the board. Other issues with my driver board persist as well
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Old 01-24-2014, 05:48 PM   #9
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Default Re: Another sony led back lighting problem.

well my replacement LED driver board came in and TV works flawless now. Those little ICs on the driver boards are a problem as it ohms out differently from the other ICS on that board. the original problem was upon startup the screen would be fine then I would lose half of the bottom left hand strip.
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Old 06-09-2014, 02:39 AM   #10
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Default Re: Another sony led back lighting problem.

The following is regarding a similar problem with a Sony Bravia KDL 40NX711 (Purchased July 2011) (3900hrs on the Panel, via the Diag menu)

This is an LED Backlit TV.

We just moved over 2000 miles and setup our Sony TV in our new home. 4 weeks after moving in the Tv turned off on it's own, it does turn back on but only stays lit for 1-2min before shutting off.

I was able to diagnose the issue through the blink code and the diagnostic menu.
It is Blink Code 6 (Backlite) Error Code 08. (also had error code 12 and 14 on 1 occasion)

I assume this is the Inverter/Driver board. See the attached images below.
I don't mind the black spot, but the tv wont stay on more than 2 min. Since it turns on and I can still see inputs, this leads me to believe the power and tcon are functioning properly.

I found the board on ShopJimmy and Ebay and hope this fixes the issue. For $10 it is worth trying.

While turned on, I can see a darker area just above the Sony emblem on the frame, about 2"x2" (It does not run the width of the screen)


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Old 06-09-2014, 02:51 PM   #11
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Default Re: Another sony led back lighting problem.

if your happy with the fault you could try and run a 100 ohm resistor from the psu side BL-ERR to ground. It will bypass the fault but may cause more damage later as it seems one of your leds have failed.
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Old 06-10-2014, 12:17 AM   #12
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Default Re: Another sony led back lighting problem.

thanks, but that sounds tricky as i am not very confident at soldiering.

Are you sure the LED is out/damaged or could it be the LED Driver Board. (I have one on order to swap out.)

How does one go about replacing the actual LEDs (I know how to replace CCFLs, but never saw a LED repair DIY)
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Old 06-11-2014, 07:06 PM   #13
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Default Re: Another sony led back lighting problem.

well.. depends on how the leds are powered, if the whole panel is powered then the one led has failed. but if they are powered individually (doubt it) then you might have a driver issue (doubt it) you will have to open the tv and removed the lcd and expose the backlight without getting dust inside, replace the led and put everything back. It could acutally be really bad backlight bleed!!! do your own research!!!
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Old 06-11-2014, 08:24 PM   #14
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Default Re: Another sony led back lighting problem.

Looks like a bad led bulb
These are normally set up in a strand, kind of like string along xmas bulbs
and sometimes one will get weak and the strand will still work.
most of the time the bad bulb will shut down the one strand and that will cause the driver board to shut all of the other strands of the bulbs.
The ones that I worked on are mostly apples, and to change those, you have to use a heatgun
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Old 06-18-2014, 01:04 AM   #15
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Default Re: Another sony led back lighting problem.

The LED Driver board replacement arrived ($10 on ebay). This did not fix the problem. So it appears to be a dead / burnt out LED.

Per the previous message, I would have to replace said bulb.
3 Options:
1. Repair Bulb (Sounds beyond my ability)
2. run a 100 ohm resistor from the psu side BL-ERR (also beyond my knowledge)
3. Take to a Sony Repair Center (sounds expensive)

Or buy a new tv.
If anyone can walk me through 1 and/or 2, I will buy a case of beer for you.
If you live in San Jose and you can help in person, even better, and more beer for you. (just after the repair)
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Old 06-18-2014, 06:02 AM   #16
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Default Re: Another sony led back lighting problem.

Changing bulbs on a screen that size will not be any fun to do !!!
here is an idea of what is involved on a 27" apple led
http://youtu.be/orJ-zEdSAAQ
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Old 06-18-2014, 10:31 AM   #17
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Default Re: Another sony led back lighting problem.

Quote:
Originally Posted by bammbammfran View Post
Changing bulbs on a screen that size will not be any fun to do !!!
here is an idea of what is involved on a 27" apple led
http://youtu.be/orJ-zEdSAAQ
jebus.

even if i manage to dismantle the tv, how would i replace 1 LED, by replacing the entire strand?

Can someone explain in detail this:
Quote:
"Use a 100 ohm resistor from the psu side BL-ERR to ground"
So locate the BL-ERR on the powerside and run a wire to the metal frame?
Is the BL-ERR easily identified?
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Old 06-26-2014, 05:03 PM   #18
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Default Re: Another sony led back lighting problem.

Quote:
Originally Posted by bammbammfran View Post
Changing bulbs on a screen that size will not be any fun to do !!!
here is an idea of what is involved on a 27" apple led
http://youtu.be/orJ-zEdSAAQ
I managed to easily dismantle the entire tv and get to the offending LEDs. The issue now is... where do i get a replacement LED strand?

3 codes are printed on the bar of 63 LEDs
SLS40_5630_120_1D_B_Rev1
I assume this is the part number
(SonyLightStrip 40" 5630 120HZ 1D? B? Revision 1)

KM-8 94V-0 1028
No idea, maybe an assemble line part #?

On the back a barcode with
K928 H
100012
40U168

Possibly an assembly / inventory # for the technician building the tv?
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Old 06-27-2014, 06:19 AM   #19
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Default Re: Another sony led back lighting problem.

how many separate bulbs board strips are on that screen ? 4 ?
how many plugs pins are on each plug of each strand or 63 ? 14 ?
can you post a few pictures ?

did you try hooking it up to see whichstrip had the trouble bulbs ?

I usually change the bad bulbs ?
I did find one used strip here but the plug might be in the wrong direction
http://www.iccfl.com/product_info.php?products_id=21543

I just enlarged those pictures and it looks like you probably have two version boards
one version has the plug on one end and the other has it on the other end
and it has 9 3 volt bulbs on each strand.
so probably they are staggered like bulb 1-8-15-23-30 etc will be on one strand and 2-9-16-24-31 etc on another
you can check one bulb at a time using a 3 volt battery or all 9 on the strand at once using a 24 volt power source (19 volt laptop adapter might just be enough to do it- if not it will do 7 at a time)
bulbs have a positive and negative side and will only light in one direction, so you have to figure out which way the first bulb of the strand travels first since some strands might have the positive side towards the main plug and some might be the reverse and start at the opposite end.

Last edited by bammbammfran; 06-27-2014 at 06:38 AM..
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Old 06-27-2014, 11:14 AM   #20
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Default Re: Another sony led back lighting problem.

What I did on a Sony Bravia 55hx850 is just remove the one troubled LED light and essentially shorted out both ends of where the LED light would connect (basically a bypass). Used it for two months like that until I received a cracked LED tv with a similar LED light. Now looks as good as new
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