Post The Led Backlights Your Fixing Here.

[theojt]

Re: Post The Led Backlights Your Fixing Here.

I have the same, one bad LED.

Did you replace the strip or just the one LED?
Where did you get your part?

Sorry for the delay, I missed your post. I replaced the strip. I got it from eBay https://www.ebay.com/itm/142219238430

$18.

[YoshiK1]

Re: Post The Led Backlights Your Fixing Here.

Hi folks,

I've did a search on the forum but can't find an answer so am posting here as this seems the most suitable place to post.

I've got an LG 42LB5500 LED TV with a backlighting issue - I still get a picture if you shine a torch on it. I've found 4 bad LEDs across multiple strips. My issue is I can't find the parts I need to replace them. I don't know much about TV parts however from research you apparently need to have the exact same parts when replacing. Is this true for LEDs?

The strips I have are:

A Strip: 6916L 1709A
B Strip: 6916L 1710A

I can find ones with similar numbers i.e. 6916L 1709B 6916L 1710B or completely different numbers but for the same TV. Am I able to use any strip that's for my TV model or does it need to be the exact same part? The connectors etc look all the same.

Thanks!

[Michale32086]

Re: Post The Led Backlights Your Fixing Here.

Hi folks,

I've did a search on the forum but can't find an answer so am posting here as this seems the most suitable place to post.

I've got an LG 42LB5500 LED TV with a backlighting issue - I still get a picture if you shine a torch on it. I've found 4 bad LEDs across multiple strips. My issue is I can't find the parts I need to replace them. I don't know much about TV parts however from research you apparently need to have the exact same parts when replacing. Is this true for LEDs?

The strips I have are:

A Strip: 6916L 1709A
B Strip: 6916L 1710A

I can find ones with similar numbers i.e. 6916L 1709B 6916L 1710B or completely different numbers but for the same TV. Am I able to use any strip that's for my TV model or does it need to be the exact same part? The connectors etc look all the same.

Thanks!

It's been my experience that if the connectors fit and the size fits, you should be OK..

[SupcoVG64]

Re: Post The Led Backlights Your Fixing Here.

I see a lot of posts where 1 or 2 led's are replaced. Given that the remaining led's are all the same age, and a strip of 100 on a slow boat from China is very inexpensive, would it not be prudent to just change all of them at the same time ?

[diif]

Re: Post The Led Backlights Your Fixing Here.

I see a lot of posts where 1 or 2 led's are replaced. Given that the remaining led's are all the same age, and a strip of 100 on a slow boat from China is very inexpensive, would it not be prudent to just change all of them at the same time ?

I wouldn't want to swap all 52 LEDs in the last couple of TVs I've repaired the LEDs on. Replaced the dead one, turned the back light down and that's it.

[nwcs]

Re: Post The Led Backlights Your Fixing Here.

I have repaired hundreds of led's in tv's and they almost always come back with more bad so I now just replace all of the led strips. And for the first time I had a Samsung UN55ES6100 that when I removed the panel to test the led's the positive wire had come disconnected from one led strip and that caused what I thought would be a bad led strip.

[diif]

Re: Post The Led Backlights Your Fixing Here.

A total of 92 LEDs in this Sony 46", edge lit top and bottom. Removed all 4 strips, but nothing faulty round. Wondering if it was a dodgy connection..

[zomi]

Re: Post The Led Backlights Your Fixing Here.

Have you tested the leds from the plug connection to see if they light up
or led to led.
Had it on a samsung where the leds tested fine.
but from the plug ta section would not light up
turned out to be a burnt trace.

[diif]

Re: Post The Led Backlights Your Fixing Here.

Have you tested the leds from the plug connection to see if they light up
or led to led.
Had it on a samsung where the leds tested fine.
but from the plug ta section would not light up
turned out to be a burnt trace.

Tested from the 15 pin connectors and also the 6 sets of 8 LEDs on each of the strips.
Think I'll reassemble and test without the LCD screen, it's possible one of the ribbon cables wasn't located properly or is damaged. Or it's the driver board.

[zdsh07p9]

Re: Post The Led Backlights Your Fixing Here.

I've been fixing TV's on the side for 12-13 years now ever since I was 14. My Dad had a Vizio 42" under his bed that was broken that I fixed with 2 caps and that started it all! Anyways - heres a list of TV's I've fixed LED's in within the last month - prepare yourselves lol:

Vizio e470i-a0
Hisense 50h5g
Sharp LC-60LE681u
Samsung UN75F6300 - yes you read that correctly. I replaced these by myself with no special contraption.
Vizio P502ui-B1E (this was because of an issue with the LED Driver board, not the actual LED's themselves)
LG 47LN5400

Anyways, the broken TV market has been pretty good to me lately.

[dskall]

Re: Post The Led Backlights Your Fixing Here.

A total of 92 LEDs in this Sony 46", edge lit top and bottom. Removed all 4 strips, but nothing faulty round. Wondering if it was a dodgy connection..

Of course if you were using an led tester to check. Main drawback is they don't drive the led's very hard. So may not break down under light load.

[diif]

Re: Post The Led Backlights Your Fixing Here.

Of course if you were using an led tester to check. Main drawback is they don't drive the led's very hard. So may not break down under light load.

I tested with my LED tester and thought the same.
I then used my bench tester set at 24v and set the current limit at 800mA, tested on each set of 8 LEDs they are drawing 60-70mA. Seems they are not drawing much current.

[dskall]

Re: Post The Led Backlights Your Fixing Here.

I think panel drives them alot harder than 60-70ma

[budm]

Re: Post The Led Backlights Your Fixing Here.

I tested with my LED tester and thought the same.
I then used my bench tester set at 24v and set the current limit at 800mA, tested on each set of 8 LEDs they are drawing 60-70mA. Seems they are not drawing much current.

You should see the current goes up much higher once you turn up the Voltage beyond 24V (I would limit the current to 100mA first) since the Vf of all 8 LEDs may not be 3V exact, some may be higher or lower you will have to look at the spec sheet of the LED.

[diif]

Re: Post The Led Backlights Your Fixing Here.

I have no idea of the spec of the LEDs but my LED tester ramped up to 22.7v per set of 8, so I figured they were 3V LEDS, hence the 24V.
The current did seem low, but they are bright at 3V, maybe they are 6V though.

[dskall]

Re: Post The Led Backlights Your Fixing Here.

Vizio will drive theirs around 400ma which is why they don't last. Funny thing is you can modify current to about half and they are still plenty bright. Makes you wonder if it is preplanned obsolescence.

[budm]

Re: Post The Led Backlights Your Fixing Here.

I have no idea of the spec of the LEDs but my LED tester ramped up to 22.7v per set of 8, so I figured they were 3V LEDS, hence the 24V.
The current did seem low, but they are bright at 3V, maybe they are 6V though.

But I thought you use 24V power supply with current limit to 800mA.
The LED tester only put out about 30mA that is why you see total Vf of only 22.70V, they are 3V LED at higher current.

[diif]

Re: Post The Led Backlights Your Fixing Here.

Yes, I set the voltage at 24V (3V for each LED) and 800mA limit (100mA) for each LED.
When I applied the probes to the sets of LEDs the power supply showed 60-70mA, I was expecting it to hit the current limit but it wasn't close.
Testing a handful of individual LEDs with the voltage set at 3v and the current limit 100mA, I see current draw between 40mA to 80mA
Why do 8 LEDs draw as much current as a single one ? I'm confused, what am I missing ?

[dskall]

Re: Post The Led Backlights Your Fixing Here.

Current is same throughout series circuit. Each led will have same current. But voltage will have to change each time you add led to maintain current

[diif]

Re: Post The Led Backlights Your Fixing Here.

Current is same throughout series circuit. Each led will have same current. But voltage will have to change each time you add led to maintain current

Of course ! I'm confusing myself unnecessarily. It's been a very long time since i did any electrical theory, thanks for jogging my memory. I went and had a little read too.