Friday, June 17, 2016

Tech Troubleshooting - Samsung LED – LCD TV – How to test the edge LED – Double image – Horizontal line – Horizontal line on the top – Vertical line - TVLN32D450G1DXZA - UN46D6900WFXZA - UN46C6300SFXZA - UN46D6420UFXZA - UN55D6050TFXZA - UN46D6900

Category: LED - LCD Television Repair and Service 

Contents of this article 

  • How to test the Edge LED
  • Double image troubleshooting
  • Horizontal and vertical lines 

Samsung LED – LCD TV

Testing the UN46D6900 LED Edge Lights
Removing the power cable from the main board and applying AC power to
the SMPS will not automatically turn on the LED back lights. Due to the Pulse Width Modulation of the “negative” signal line, some additional steps are required. See instructions and pictures below. (Sample unit pictured has a confirmed
good working SMPS.)
1. Remove the AC power cord.
2. Disconnect the power cable from Main PCB, CN201 (SMPS, CNM802 to Main PCB, CN201). Notice connector cable is double layered with odd number pins on the top and even numbered pins on the bottom.
3. On the disconnected cable end, insert a jumper wire between pin 18 (A5V) and pin 2 (PWM4). {See Picture A.}
4. Reconnect the AC power cord and apply AC power.
5. Confirm that the lower left and right LED sight holes are brightly illuminating. This indicates the lower 1/4th of the  panel edge LED lights are working correctly. {Left side shown in Picture B.}
Repeat this process for the rest of the PWM signals (PWM1, PWM2 and PWM3) in connector cable pins 4, 6, and 8 respectively. Shorting each to A5V should illuminate the next 1/4th of the panel edge LED lights (going bottom to top) which can be verified by looking at the appropriate LED sight holes. See additional pictures below:
SAMSUNG LN32D450G1DXZA
Symptom: Vertical line.
Run the Picture Test function. If the vertical line appears In the test picture, replace the panel.
SAMSUNG UN46D6900WFXZA
Symptom: The picture is doubled. Each part is seen in duplicate
Replace the T-Con board.
SAMSUNG UN46C6300SFXZA
Symptom: Vertical line.
Bring up the OSD menu. If the line goes through the menu, the panel is bad. Replace the panel. If the line goes behind the menu, disconnect all signal sources and check again. If the line is still there, change the main board. If the line has disappeared, then the signal source is the cause of the problem.
SAMSUNG UN46D6420UFXZA
Symptom: There are two horizontal lines on top of the screen.

Bring up the OSD menu. If the lines go through the menu, the problem is with the panel. Replace the panel. You can confirm that the problem is with the panel by running the internal test pattern (the green picture above). If the lines appear when you run the internal test pattern, the panel is the cause.
SAMSUNG UN55D6050TFXZA
Symptom: Horizontal line across the screen.
Bring up the OSD menu. If the line goes thru the menu, the panel is bad. Replace the panel. If the line is behind the OSD menu, disconnect all signal sources and check again. If the line is still there change, replace the main board. If the line has disappeared, then the signal source is causing the problem.