TV repair issue with led backlight not lighting


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TV repair issue with led backlight not lighting

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Fraser1978
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Mar 2, 2017, 12:07 PM

Post #1 of 14 (8381 views)
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TV repair issue with led backlight not lighting	Can't Post

Hi everybody really happy to have found this forum! I have a huge problem and need to get it sorted ASAP as I currently have my TV in bits and the missus is getting impatient with no TV in the living room! Haha.
So I've had a few issues getting this tv going. I started off with a TV that had no power but screen intact. The replacement board was out of stock everywhere I looked. So i bought a compatible board from a different brand of TV and it would of been great as it added an extra usb port, but what i didnt anticipate was that the new port only had 1 socket for the leds and the old one had 2. So there's 4 strips in the TV and its direct lit and there are 4 wires split into 2 sets which form a plug on each and they plug into 2 led power ports on the board. Now I've tested all led strips firstly testing the whole strip then testing each individual led one by one and they all lit fully no problem. So plugging in both plugs doesn't do anything. Plugging in just 1 doesn't do anything, bearing in mind the last tv board lit up 2 strips no problem. So here's the funny thing, if i plug in both sets then short circuit the 2 wires together from one plug then 2 strips will light up! Weird. Now for my experience so people know how to reply. I'm tech savvy as I repair mobiles, tablets and pc's for a living, I know basic soldering and can figure out basic electronics pretty easily I just don't know all the terms and voltages etc etc.
Would assume this is unrelated, but the board i have is the dvd version but I have the TV without dvd. There are 2 ports on the board for dvd, 1 for data and 1 for power. I would assume that this doesn't matter as the power going to the leds would be exactly the same yes? Or maybe the dvd has to be plugged in to distribute power correctly? If so can I short/bridge something to fix it? This is where I would need direction if that's the case.

I hope all of the above makes sense and really need help quickly so I appreciate any fast responses I get! Cheers!

Fraser

jts1957
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Mar 2, 2017, 4:01 PM

Post #2 of 14 (8368 views)
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Re: [Fraser1978] TV repair issue with led backlight not lighting [In reply to]	Can't Post

So much for being able to do any research. Unimpressed

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Fraser1978
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Mar 4, 2017, 7:01 PM

Post #3 of 14 (8346 views)
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Nobody any ideas? Please guys I'm really stuck

jts1957
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Mar 4, 2017, 7:56 PM

Post #4 of 14 (8344 views)
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Re: [Fraser1978] TV repair issue with led backlight not lighting [In reply to]	Can't Post

If you insist on only giving out non-specific facts, you will only get vague ideas. Frown

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Location: Far, Far Away

Fraser1978
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Mar 5, 2017, 3:34 AM

Post #5 of 14 (8338 views)
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Re: [jts1957] TV repair issue with led backlight not lighting [In reply to]	Can't Post

That really isn't very fair though is it? If I knew where I needed to be more specific then I would try to be helpful and give those specifics. The whole reason for my post was to gain the knowledge needed to finish the repair, and if i was a tv repair technician then perhaps I wouldnt be asking in the first place. There is no need to be rude I have tried to give all the relevant info required, please forgive me if I am a little lacking in knowledge in this field.

However if it helps, I have the model number of the board, however, I thought boards were specific to the TV model number so assumed this information was irrelevant? Perhaps I was wrong. Board model number is TP.MSD309.BP710. There is no power board, tcon board or led driver board only the main board which contains all connections including power, lvds, ir/buttons, led strips and speakers. All of the external connections are also part of the main board. There is the main board and the thin board that is attached to the lcd itself I believe it's called the lvds board is that correct? I will upload some photos somewhere so I can follow this post with some photo links to help? Is that satisfactory enough for you to offer your advice?

Thanks.

Fraser

Fraser1978
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Mar 5, 2017, 3:58 AM

Post #6 of 14 (8339 views)
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Re: [jts1957] TV repair issue with led backlight not lighting [In reply to]	Can't Post

Main Power area of main board

[URL=http://s1250.photobucket.com/user/Fraser_John_Dalgleish/media/1488681759216671324659_zpsecp2v8cc.jpg.html]

Led power sockets area (please ignore my wiring, it's temporary before final soldering incase polarity is wrong. I also wanted to make sure no ends had split wires)

[URL=http://s1250.photobucket.com/user/Fraser_John_Dalgleish/media/14886817135951879207993_zpsyyhq8hxt.jpg.html]

Led power socket area (another angle)

[URL=http://s1250.photobucket.com/user/Fraser_John_Dalgleish/media/14886816529482077177675_zpsfg7j3ufx.jpg.html]

Overall view of main board location and 4x led strips in their entirety (please note lcd is being stored safely and separately as it's only the leds I need test)

[URL=http://s1250.photobucket.com/user/Fraser_John_Dalgleish/media/14886816312661902134363_zpsqwzay0tl.jpg.html]

Close up of the led strips and their matching model numbers.

[URL=http://s1250.photobucket.com/user/Fraser_John_Dalgleish/media/14886815996741608079907_zpskrs1du1e.jpg.html]

Overall view of main board

[URL=http://s1250.photobucket.com/user/Fraser_John_Dalgleish/media/1488681554893-716865898_zpsshfiooqr.jpg.html]

I hope above images help anybody to answer

jts1957
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Mar 5, 2017, 4:27 AM

Post #7 of 14 (8332 views)
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Re: [Fraser1978] TV repair issue with led backlight not lighting [In reply to]	Can't Post

https://youtu.be/XI7oKTq7IyU

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Location: Far, Far Away

Fraser1978
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Mar 5, 2017, 4:54 AM

Post #8 of 14 (8329 views)
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Part number B14060500-0A00781

LVDS is V400HJ6-PE1 75w1 rohs

I don't think I can be any more specific and I have a 2 year old daughter who is missing out on her morning TV so any help now would be much appreciated. Thanks

jts1957
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Mar 5, 2017, 5:33 AM

Post #9 of 14 (8326 views)
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Re: [Fraser1978] TV repair issue with led backlight not lighting [In reply to]	Can't Post

Does the set have a 'Brand?'
Does the set have a label on the back with a 'Model Number?'
Does that board have and searchable numbers on the top or back?

Perhaps:
http://www.ebay.ie/...0-223I-/141686272493

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Location: Far, Far Away

(This post was edited by jts1957 on Mar 5, 2017, 5:37 AM)

Fraser1978
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Mar 5, 2017, 5:37 AM

Post #10 of 14 (8323 views)
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Re: [jts1957] TV repair issue with led backlight not lighting [In reply to]	Can't Post

Sorry I missed that out. Bush 40/233f

Fraser1978
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Mar 15, 2017, 11:30 PM

Post #11 of 14 (8230 views)
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Re: [Fraser1978] TV repair issue with led backlight not lighting [In reply to]	Can't Post

Can nobody help?

dfear
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Mar 17, 2017, 9:10 PM

Post #12 of 14 (8213 views)
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Re: [Fraser1978] TV repair issue with led backlight not lighting [In reply to]	Can't Post

I have a very similar problem.

I have a BLAUPUNKT 40/2331-GB-5B2-FHKUP-UK 40" LED TV with a NO BACKLIGHT problem.

The main board is: tp.msd309.bp710
The LCD panel is: v400hj6-pe1

I tested the voltages going to the LED backlights. The connectors are marked CNB801 AND CNB806. On CNB801 I have 28 VDC and on CNB806 I have 0 VDC.

Fraser1978 - what voltages do you have and how did you test the backlights?

Slydder
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Sep 16, 2018, 9:50 AM

Post #13 of 14 (6547 views)
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Re: [dfear] TV repair issue with led backlight not lighting [In reply to]	Can't Post

Has anyone been able to find a service manual or schematics for this mainboard? This seems to be a bit of a popular board. I have seen it in baupunkt and sharp equipment and am constantly having to fly blind with it.

dfear
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Nov 7, 2018, 7:13 PM

Post #14 of 14 (6287 views)
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In Reply To

I have managed to fix the problem with my TV, it was a single faulty LED on one of the led strips.

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