POWER SUPPLY [SMPS] BOARD
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POWER SUPPLY PWB _ LOW-VOLTAGE TESTAC Should not be applied at any time while adding resistors or while unplugging connectors as damage tothe circuit PWB may occur.
a) The SMPS PWB “MUST” be producing STBY 5V on all of the pins 7, 8, 9 or 10 (5V). If 5V Standby is not being generated, the SMPS PWB is defective and must be replaced. There is no need to continue with the next test.
(b) Unplug P2400 on the Main PWB.
TEST 1:
(1) Add a 100Ωresistor between (5V STBY) pin 7, 8, 9 or 10 and Pin 2 (PWR). Apply AC. This will turn on the power supply.
a) Check that the 24V and 12V power supplies are turned on,
• P201 (24V pins 17 and 18)
• P201 (12V pins 13 and 14)
(2) Remove AC power.
POWER SUPPLY PWB _ BACK-LIGHTS TEST
P2400 Connector disconnected from the MainPWB. Apply AC after adding jumper.
Continue if the 1st test was OK. Leave original resistor in place.
(3) Add another 100Ωresistor between (5V) pin 7, 8, 9 or 10 and Pin 20 (INV On).
(4) Apply AC Power. Simulating a Power and Backlight On command.
Backlights Normal:
a) If normal, the backlights should turn on. SMPS OK.
Backlights Abnormal:
a) Recheck all connections.
b) Confirm the INV On/Off line pulling up to at least 3V.
REMOVE AC POWER:
c) Check the connections to the Backlights.
DO NOTcheck these when AC is applied as they carry 1200V each.
Note, either of the connections are unplugged, the backlights will not light.
POWER SUPPLY CONNECTOR-P201 VOLTAGE & DIODE CHECK
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ADIM Pin 21 Fixed and not used.
PDIM Pin 24 can vary according to type of signal being processed and the OSD Backlight setting.
0.6V 0% to 3.3V 100%. Output from the video processor IC100.
Diode Mode values taken with all Connectors Removed.