Set was hit by lightning. Replaced ac fuse and shorted D621 200v zenor diode. Set worked OK. Ben gone from shop for close to a month and brought back. Customer said that TV was hard to turn on, after it was on, it played OK. After several days of turning set on and off and on, what I see is the white power led coming on for a short while, then going off before the Philips logo comes up. Have monitored the inverter leads to the panel with a scope and get just a momentary pulse from the inverters. Need an idea, also need a diagram for this product. Thanks, David
If the tv was struck by lightning, it is highly possible the motherboard got faulty as well. Remove the power board and get it enabled across low ohm resistor using 5V from standby pin. Once the PSU turns on, measure all voltages with your scope and check the level of AC ripple. Load 24V line with light bulbs ensuring it consumes the max amount of power as it says on the b/d. In this condition your b/d should be outputting all voltages with no ripple. If the board is fine, you should focus on your main board, but let me know how you get on with your power supply first.