Samsung UA43RU7100 – Service mode – power board troubleshooting

Samsung 43,50,55,58,65 and 75 inch LCD TV power board and back-light inverter troubleshooting

Applicable to UA43RU7100K, UA50RU7100K, UA55RU7100K, UA58RU7100K, UA65RU7100K, UA75RU7100K

Function Control Operation Test

1. Place TV in Power Standby
2. Check LED Status
3. If LED is OFF:

LED 1.7Vdc (pin 8 ) and VCC for 3.3Vdc (pin 3 )

If missing suspect Function Assy/Cable/Main board.

4. If LED is ON:

Switch Operation activates on screen display

If missing:

Key_Input 1 (pin 6 ) change to 0V with a command.

If wrong voltage or no change:

Switch for stuck or miss-operation.

5. Check IR operation with Standard Remote command changes.
6. Check SDA, SCL for effective 3.3Vdc. (after power on)
If missing suspect Function Assy/Cable Assy./Main Assy

Power: SMPS Standby: 43 inches – connector voltages.

50/55/58 inches SMPS connector voltages.

65 inches SMPS connector voltages.

75 inches SMPS connector voltages.

TV power standby test.

1. TV in Standby
 Check Standby LED Indicator.
2. If Not Lit:
 Check AC 120Vac Line.
3. If missing:
 Check AC120Vac Source/Power Cord.
4. If OK:
 Check resistance on SMPS FUSE after first removing AC power cord.
5. If fuse/s are open : replace SMPS.

6. If fus are OK:

  Standby: A13V (Always On) to Main Board.
7. If any missing remove the SMPS connector to the Main Board.
9 Check Standby A13V again.
 If OK replace the Main Board.
 If still missing replace SMPS.

SMPS Power On: 43 inches.

SMPS Power ON: 50/55/58 inches.

SMPS power ON: 65 inches.

SMPS Power ON: 75 inches.

Power ON sequence test.

1. Power TV On.
 Power_On/Off / POWER_ON (pin 8 ) 0.2Vdc (when off) changes to 3.3Vdc (on). [There is an approx 20 second delay from PS-ON to off condition when the TV is powered off, and approx a 2 minute delay when the TV is first plugged into AC Power]

2. If voltage error or no change:

9 Jog Function Control Test.
3. If OK replace Main Board.
9 All A13V supplies for approx. 12.7VDC (pins 3 , 5 , 7 , 9 )
4. If any wrong voltages, remove SMPS connector to Main Board.
9 All A13V again for 12.7VDC (pins 3 , 5 , 7 , 9 )
5. If OK replace Main Board.
6. If still wrong voltage replace SMPS.

    9 OD_ON/OFF (Over Voltage Detect) (pin 4 ) 3.3Vdc : Operating Normal.

7. If 0V or changing, an SMPS or Panel error exists. Perform Backlight Test.
9 BLU_PWM / PWM_BLU (pin 6 ) Backlight On/Off & Dim Control : 1Vdc – 3.3 Vdc depending on backlight dimming level for video.
• If missing or error : Replace Main Board.

SMPS / PANEL BACKLIGHT (Parallel Wired SMPS Panel Connections)

43, 50, 55, & 58 inches

65 and 75 inches.

Backlight Test :
1. Activate Backlights Test : Disconnect Lead Cable from Main to Power Supply.
 Check TV Screen for active backlight LEDs.
2. If No Backlight.
 Minus (Control) pins & Plus (Supply) pins voltages on the Panel Connector. (with fine test probe on left side of connector only for safety)
 If no pin voltages replace SMPS.
3. If Backlights ON BUT PANEL SECTION(S) OFF:
 The Supply Drive (+) pins and (-) pins. All should measure same.
 If a Minus (-) pin measures low (near 0 volts), a string(s) of LEDs are likely open.
  Replace Panel.
 If a (+) pin measures low voltage.
  Defective SMPS.

BACKLIGHT DIMMING PROBLEMS :

• Go to Menu > Picture > Backlight and vary level (0 – 50).
• If no backlight changes observed:
 Panel Connector CNL801 minus (-) pin voltages and PWM_BLU control voltages CNM801 while changing backlight level.
• If minus (-) pin voltages don’t change, and PWM_BLU changes, replace SMPS.
• If PWM_BLU doesn’t change replace Main/T-Con Board.

Backlight Test : In normal TV operating mode, use standard IR Remote or Factory Remote with commands.
Go to (MUTE > 4 > 1 > 9 > EXIT)

Netflix Operation/Connection Issues.

Check Certificate & Netflix ESN Status in Factory Mode.

If Certificate and ESN exists, "CO", "NfO", change the DNS to 8.8.8.8
• If Certificate is missing, "C/" replace the TV’s Main Board.
• If ESN number is missing: NF/ do not replace the Main Board.
- Reset TV Clock and check for correct Time & Date. 

Netflix relies on correct settings.
- Reset Smart Hub. / Reset Apps In Factory Mode.

For Streaming Issues.

Go to TV Web Browser / Go to speedof.me / testmy.net
Check Speed for at least 5 Mbps(HD streaming) / 25 Mbps (4K Streaming).

Check Latency for less than 50ms.

Setting TV into Factory Mode

Factory Remote.

1. Power TV ON.
2. Select TV Source.
3. Info > Factory.
4. Use MENU for return.

Samsung IR Remote.

1. TV Power Standby.
2. Press as follows.
• Remote Buttons (NTSC-MUTE 1 8 2 POWER) 

PAL  INFO MENU MUTE POWER

Important Items.
• Option (must set Option Bytes when replacing Main Board.)
• Option > Factory Reset (returns TV to out of box condition.)
- Must perform when replacing Main Board or Full One Connect)

Factory Reset : Select Factory Reset.

SVC > Info > ER Count (Important to check for errors.)
- Resets to 0 with Factory Reset.
Check before resetting TV
• SVC > Test Patterns (Use to check / troubleshoot) videos errors.
• Control > EDID (Use to Reset HDMI Operational Errors)

Setting Option Bytes.

1 Enter Factory Mode with Service Remote (only).
2. Check Option Byte Table located on GSPN (Fast Track or Tips).
3. Select Option.
4. Select each item to change.
5. Can Use new Writing Type to enter model (if entered wrong it will not change.)

6. Soft power TV Off to load.

Performing Factory Reset.

Enter Factory Mode.
2. Select Option > Factory Reset
3. TV will power off.
4. Perform ALL TV Settings. (New out of box condition)

Details: UA65RU7100KXXV

Main board