Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting TVs and Video Sources
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 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
Default 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
provider10 is offline   Reply With Quote
Old 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
Default Re: Samsung UA50f Backlight problem

Can you post good clear straight shot pictures of the whole back and each board.
nomoresonys is offline   Reply With Quote
Old 11-20-2019, 09:26 AM   #3
provider10
New Member
 
Join Date: Mar 2016
City & State: Western Cape
My Country: South Africa
I'm a: Knowledge Seeker
Posts: 10
Default Re: Samsung UA50f Backlight problem

Hope these pics help. I think the model in UK is UN50F
Attached Images
File Type: jpg 20191120_171623.jpg (439.8 KB, 6 views)
File Type: jpg 20191120_171635.jpg (772.9 KB, 5 views)
File Type: jpg 20191120_171640.jpg (546.9 KB, 4 views)
File Type: jpg 20191120_171650.jpg (463.2 KB, 8 views)
provider10 is offline   Reply With Quote
Old 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
Default 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..
neilc6 is offline   Reply With Quote
Old 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
Default 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
provider10 is offline   Reply With Quote
Old 11-20-2019, 11:25 AM   #6
budm
Badcaps Veteran
 
budm's Avatar
 
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
Default 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
budm is online now   Reply With Quote
Old 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
Default 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
provider10 is offline   Reply With Quote
Old 11-21-2019, 12:06 AM   #8
provider10
New Member
 
Join Date: Mar 2016
City & State: Western Cape
My Country: South Africa
I'm a: Knowledge Seeker
Posts: 10
Default Re: Samsung UA50f Backlight problem

sorry pics did not attach
Attached Images
File Type: jpg 20191121_075612.jpg (325.8 KB, 4 views)
File Type: jpg 20191121_075813.jpg (819.1 KB, 2 views)
provider10 is offline   Reply With Quote
Old 11-21-2019, 12:08 AM   #9
budm
Badcaps Veteran
 
budm's Avatar
 
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
Default 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..
budm is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 07:22 PM.
Did you find this forum helpful?