LG 42LG60 Manual page 28

Power Supply PWB Test (2 nd Test All Including Backlights)
Power Supply PWB Test (2 nd Test All Including Backlights)
P2 Connector disconnected from the Main PWB. Apply AC after adding jumpers.
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If the 1 test was successful, continue. Leave original 10K in place.
(2): Test the Backlights, jump Pin 19 (PWR) to Pin 20 (INV) and apply AC Power to the PWB.
Observe the Backlights. If normal, the backlights should turn on and off 4 times then go off.
If only ½ the backlights light, (Right side or Left Side), confirm connectors are OK. Check
Transformer Left and Right center pins for signal. If OK, panel defective, backlight failure. If
pulse is missing on one side (L or R Center) of the transformer, power supply defective.
If no backlight activity, confirm the Fuse F700 has approx. 300V on both sides.
If only on one side, check fuse for open. If no 300V, replace Power Supply.
If 300V DC is present, observe the L and R center legs on the left hand side of ballast
transformer T701. Look for 58Khz pulse at 8.7V p/p. If yes, confirm connectors to backlight
OK. If OK, then panel is defective. If no pulse is found, replace the Power Supply.
LCD DV 42LG60
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