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.
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.
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.
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
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.
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.
- 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