PN51E490 B4FXZA Samsung plasma TV troubleshooting

Power Supply Trouble Shooting

VITAL SIGNS check Vs, Va, Vsc & Ve When troubleshooting, It’s very important to first check Vs, Va, Vsc & Ve

If Vs is missing (0V), disconnect power and check for short. Use ohm meter to measure resistance while disconnecting Y/X-Board supply feed.

* Turn Power On and Test SMPS with short connector removed for correct Vs voltage verification. (It may only come up briefly but to full level). Again be careful not to reconnect Power Connectors until Vs falls below 10V

* If Va is low or missing, disconnect Supply Feed to Logic Buffer Boards and check to see if SMPS Supply is restored.

* If Vsc is low or missing and Vs was OK, the failure is with the Y/XBoard since the Y-Board section generates the Vsc voltage from the Vs supplied by the SMPS.

* If Ve is low or missing and Vs is OK, the failure is with the Y/X-Board since the Ve is generated by the X-Board section from the Vs supplied by the SMPS.

Other SMPS Voltages:
Check Low Voltage feeds to the Main Board and other supplied Assemblies.

Over Current Protection

For the SMPS Power Supply... If a short circuit occurs on either the VS or VA voltage lines, the SMPS stops operating, but should not fail. When the short circuit is removed from the source line, the Power Supply will operate normally again. Many SMPS Supplies are replaced needlessly.

2010/2011/2012 models

Will not be run when the “X“ or “Y” or “Y/X” Main are disconnected. The SMPS will shut down immediately. However if a meter is first connected to the test point when power is applied it will read the correct voltage briefly before shutting down.(You have enough time to check key voltages)

CAUTION: Do not reconnect any connectors to SMPS or Y/X Board(s) until power has been turned off long enough for Vs to drop below 10V or damage will occur to X/ Y Board(s).

Activating power and logic board test pattern without main board.

* Remove power cord to panel.

* Short Highest 2 pins# on Logic Board.  Test jig (can be 4 pin or 6 pin)

* Remove power connector at main board [keeping connection to [SMPS]

* Short “Power On” pin to circuit Ground on power connector to SMPS.

* Connect the power cord to panel.

Click on the pictures to magnify

Function Control Troubleshooting

5 directional function controls [UNEH4000 sample]

Standby A3.3V on Function Connector, Pin 3.

All Pins should read 3.3V before commands.

Press, at Key 1, Pin 6. 3.3V to 0.0V DC

Left, Right, Up, Down at Key 2, Pin 7.  Check specific voltages on chart.

All functions can be tested in Standby Mode.

VIDEO PROBLEMS

Verify Video Operation:
A. Customer Picture Test
B. “Display”
C. If display & Customer Picture Test are OK source is suspected
D. Substitute with known good source and cabling.

Using Test Patterns in Service Mode:
Customer Remote
A. Power off
B. Mute, 182, Power
Factory Remote:
A. Power On
B. Info, Test.

Verify M-STAR Patterns
4. Verify Logic Patterns

If Logic Patterns are OK and MStar are noisy, replace the defective LVDS Cable or Main Board.
If M-Star and Logic Patterns are both noisy check for specific on screen noise error to determine failure.

ON SCREEN FAILURE EXAMPLES:

NOTE: X/Y MAIN Combined.

ALIGNMENTS

Check/Adj. VS, VA, VE, & VSC according to Panel Label and Diffusion test.

DIFFUSION TEST/ADJ. (cell miss-firing)
- Allow the unit to warm up 15 to 20 minutes
- Access the Burn Protect Sig. Pattern in Cust. Menu.
-Adjust the Vs volts until screen errors are gone in both dark and bright areas.
-Adjust the Vs volts within +/- 10V on the panel label.
-NOTE: Diffusion may appear with aging panels.
New panels with Diffusion report problem.

Check/Set Option Bytes:

E490 Supply Adjustments

E490 Power on sequence