UN60J6200AFXZA Backlight issue

[ShatterMasters]

Hello!

I got a TV in my repair store with symptoms of bad LED's. We tore it down and tested the LED's and found bad ones so we ordered replacement strips.

Now after replacing the strips they still are not wanting to turn on. Its like the PSU is not detecting the LED's because the return lines at the connector are the same as the output. Ive tested for bad connectors and can't seem to find any.

Not sure what to do now!

[neilc6]

Re: UN60J6200AFXZA Backlight issue

Bad LEDs can damage the power supply. Seen damage to diodes, FETs and the controller IC. Pictures of the power supply board?

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

I noticed its pretty dark by LED output. It is outputting 403v and taking back 403 on the other side

[neilc6]

Re: UN60J6200AFXZA Backlight issue

Did you check those diodes and the FET in that darkened area for shorts?

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

Did you check those diodes and the FET in that darkened area for shorts?

I have not yet. In my mind I was thinking if it output power then the board was most likely working. I can do that though!

[budm]

Re: UN60J6200AFXZA Backlight issue

Remove D9001C and check the RESISTANCE in both directions, it should not show resistance in BOTH directions.

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

Remove D9001C and check the RESISTANCE in both directions, it should not show resistance in BOTH directions.

I saw your post about this on another thread with the same PSU.

Just tested it and it looks like it is getting the same both ways. 0.1 OHM's.

[budm]

Re: UN60J6200AFXZA Backlight issue

I saw your post about this on another thread with the same PSU.

Just tested it and it looks like it is getting the same both ways. 0.1 OHM's.

Replace it.

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

Sorry that was for BB90004

D9001c get 5.6k one way and 3.0k the other direction. So your answer will be the same to replace it. I'll see if I can find one on DigiKey

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

Replace it.

Does this look like the correct one?

https://www.digikey.com/product-deta...QaAh64EALw_wcB

[budm]

Re: UN60J6200AFXZA Backlight issue

What is the P/N of the bad one?

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

What is the P/N of the bad one?

Couple different sets of numbers but SF28G is what I think it is.

Others are jf25, siyu

[budm]

Re: UN60J6200AFXZA Backlight issue

That replacement is fine.

[ShatterMasters]

Re: UN60J6200AFXZA Backlight issue

That replacement is fine.

Thanks for the quick help! You are the man.

[bottemann]

Re: UN60J6200AFXZA Backlight issue

More feedback for the group.
I just fixed my UN60J6200 which had the identical issue.
Found 40 shorted and 1 open LEDs.
After installing a new LED set from shopjimmy,
it still didn't work, though they lit up with the LED tester.
PSU (BN44-0775A) had a bad C9001 diode (SF28G) which
showed 900 ohms both ways. Used a junk box NTE577.
Awesome!

[budm]

Re: UN60J6200AFXZA Backlight issue

Thanks for the feedback on your repair.

[neilc6]

Re: UN60J6200AFXZA Backlight issue

I got one of these and waiting for new strips but suspected power supply damage because in Samsungs, the screen is normally dim with no shutdown from shorted LEDs. For search purposes, corrected power supply part number is BN44-00775A . SF28G is 2A/600V and available from Digikey.

[neilc6]

Re: UN60J6200AFXZA Backlight issue

I replaced all the strips (63 out of 84 LEDs were shorted) and D9001 tested ok. Usually if the FET and diode test good, I suspect the controller IC is damaged. Board is pretty expensive on Ebay but Buyqual sells a substitute board. I have ordered a substitute board from them previously and it was ok.

[Plurxtc1]

Re: UN60J6200AFXZA Backlight issue

Is the controller IC the 7014X?

[neilc6]

Re: UN60J6200AFXZA Backlight issue

Is the controller IC the 7014X?

I've got 3 damaged power supplies from Samsungs with bad backlights. Diode and FET all tested good and no backlight with all new strips and ended up replacing the power supply.

The other two are BN44-00772A from UN50H6203 and BN44-000769C from UN40H5203. I can only see the marking clearly on BN44-00772A as 7014X.

Might as well order some on Aliexpress and see if it fixes these 3.