SAMSUNG PN50C450B1 - POWER SUPPLY [SMPS] TROUBLESHOOTING
Firmware: Check Samsung.com for latest update - 3/16/11 IMPORTANT -T-SAT4AUSHC(1008.2 or
1008.3).EXE
You should check
serial number and bulletin before updating firmware.
Reason: Red Dot issue. Buzzing noise
level will be reduced.
Activating Power & Logic Board test patterns without main board.
* Remove the power cord to panel.
* Short the Highest two pins on the logic board.
* Remove the power connection at the main main board; keeping connection to
SMPS. Short the Power ON pin to circuit ground on power connector to SMPS.
* Connect the power cord to panel.
2010/2011 models
Will not be run with the “X” or “Y” main 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 Boards until power has been turned off long enough for Vs to drop below 10V or damage will occur to X or Y Boards.
Will not be run with the “X” or “Y” main 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 Boards until power has been turned off long enough for Vs to drop below 10V or damage will occur to X or Y Boards.
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.
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.
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-Board & X-Board supply feeds one
at a time. 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 Address Boards and Check to see if SMPS Supply is restored. (Note
Va feed normally passes through the Y-Drive to the Address Boards (Logic Buffer
Boards).
If Vsc is low or missing and Vs was OK,
the failure is with the Y-Board since
the Y-Board generate 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 X-Board since
the Ve is generated by the X-Board from the Vs supplied by the SMPS. Please
note in some rare cases the Ve may be generated by the Y-Board feed to the
XBoard.)
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.
CLICK ON THE PICTURES TO ZOOM IN