Samsung UA50f Backlight problem

provider10 · 11-20-2019, 04:50 AM

Hi
Got this samsung UA50f I think the a is because i live in south Africa.
This set has 9 rows of LED strips . The top 5 rows come on fully bright but the bottom 4 come on dull. The lights are only on for a second or so then they all switch of . and a relay can be heard clicking. I chaned one of the dull strips with the bright one and still the same so I dont think its the LED strips.
Any help would be appreciated

James

**nomoresonys** · 11-20-2019, 08:20 AM

Can you post good clear straight shot pictures of the whole back and each board.

provider10 · 11-20-2019, 09:26 AM

Hope these pics help. I think the model in UK is UN50F

**neilc6** · 11-20-2019, 10:21 AM

Check if you have good continuity through the connector. You may also have bad backlights.

https://www.badcaps.net/forum/showthread.php?t=72299

provider10 · 11-20-2019, 10:52 AM

The back lights are good as i changed one of the dim set to a position where they were bright and the leds lit up good

**budm** · 11-20-2019, 11:25 AM

You have FOUR LED drivers so you need to check the Boosted Voltage output of each driver when you first turn on the TV.
Your pictures are too blur to be able to read any prints on the boards.

provider10 · 11-21-2019, 12:03 AM

Hope these pictures help. The problem is the set does not stay on long enough to make any measurements

James

provider10 · 11-21-2019, 12:06 AM

sorry pics did not attach

**budm** · 11-21-2019, 12:08 AM

You are looking to see how high the LED drive Voltage jumps up to when TV is first turned on, so you will have to repeat the test 4 times to see if they all jump up to the same level or not before the protection circuit kicks in. Set meter to 200 Vdc scale or higher.
What is the power supply board P/N? BN44-?????.
There is Voltage chart printed on the board.
EDIT: I now see the board P/N BN44-00624B.
Can we get good clear straight shot of the whole top and bottom side of the power supply board?

11-20-2019, 04:50 AM	#1
provider10 New Member Join Date: Mar 2016 City & State: Western Cape My Country: South Africa I'm a: Knowledge Seeker Posts: 10	Samsung UA50f Backlight problem Hi Got this samsung UA50f I think the a is because i live in south Africa. This set has 9 rows of LED strips . The top 5 rows come on fully bright but the bottom 4 come on dull. The lights are only on for a second or so then they all switch of . and a relay can be heard clicking. I chaned one of the dull strips with the bright one and still the same so I dont think its the LED strips. Any help would be appreciated James

11-20-2019, 08:20 AM	#2
nomoresonys Badcaps Veteran Join Date: Jan 2013 City & State: midwest My Country: U.S. I'm a: Knowledge Seeker Posts: 4,470	Re: Samsung UA50f Backlight problem Can you post good clear straight shot pictures of the whole back and each board.

11-20-2019, 10:21 AM	#4
neilc6 Badcaps Veteran Join Date: Nov 2015 City & State: BC My Country: Canada I'm a: Knowledge Seeker Posts: 665	Re: Samsung UA50f Backlight problem Check if you have good continuity through the connector. You may also have bad backlights. https://www.badcaps.net/forum/showthread.php?t=72299 Last edited by neilc6; 11-20-2019 at 10:34 AM..

11-20-2019, 10:52 AM	#5
provider10 New Member Join Date: Mar 2016 City & State: Western Cape My Country: South Africa I'm a: Knowledge Seeker Posts: 10	Re: Samsung UA50f Backlight problem The back lights are good as i changed one of the dim set to a position where they were bright and the leds lit up good

11-20-2019, 11:25 AM	#6
budm Badcaps Veteran Join Date: Feb 2010 City & State: S.F. Bay area My Country: USA Line Voltage: 120V 60Hz I'm a: Knowledge Seeker Posts: 36,657	Re: Samsung UA50f Backlight problem You have FOUR LED drivers so you need to check the Boosted Voltage output of each driver when you first turn on the TV. Your pictures are too blur to be able to read any prints on the boards. __________________ Never stop learning Basic LCD TV and Monitor troubleshooting guides. http://www.badcaps.net/forum/showthr...956#post305956 Voltage Regulator (LDO) testing: http://www.badcaps.net/forum/showthr...999#post300999 Inverter testing using old CFL: http://www.badcaps.net/forum/showthr...er+testing+cfl Tear down pictures : Hit the ">" Show Albums and stories" on the left side http://s807.photobucket.com/user/budm/library/ TV Factory reset codes listing: http://www.badcaps.net/forum/showthread.php?t=24809

11-21-2019, 12:03 AM	#7
provider10 New Member Join Date: Mar 2016 City & State: Western Cape My Country: South Africa I'm a: Knowledge Seeker Posts: 10	Re: Samsung UA50f Backlight problem Hope these pictures help. The problem is the set does not stay on long enough to make any measurements James

11-21-2019, 12:08 AM	#9
budm Badcaps Veteran Join Date: Feb 2010 City & State: S.F. Bay area My Country: USA Line Voltage: 120V 60Hz I'm a: Knowledge Seeker Posts: 36,657	Re: Samsung UA50f Backlight problem You are looking to see how high the LED drive Voltage jumps up to when TV is first turned on, so you will have to repeat the test 4 times to see if they all jump up to the same level or not before the protection circuit kicks in. Set meter to 200 Vdc scale or higher. What is the power supply board P/N? BN44-?????. There is Voltage chart printed on the board. EDIT: I now see the board P/N BN44-00624B. Can we get good clear straight shot of the whole top and bottom side of the power supply board? Last edited by budm; 11-21-2019 at 12:21 AM..

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