LG Flatron W2252TQ-TF P.S. Board

[SgtRock]

Greetings BadCappers:

--I am trying to repair the Power Supply Board for an LG Flatron W2252TQ-TF. It will not turn on because the 5V rail is only producing about 1.6VDC. I have checked the board over with a Fluke 87 DMM, and so far the only thing I can find which stands out as bad is Zener Diode ZD101. I reads short in both directions and shows 1.6VDC with the board plugged in, so I am pretty sure that is not the only problem, but I do not know where to start. I did find the 22VDC present at U304 & U303 which are about 1/3 of the way from top.
--Does anyone know where to find a schematic?
--Can anyone make an informed guess as to the voltage of ZD101?
--If I order a selection of 1/2 Watt Mini MELF Zeners from Digikey, to have in stock, what commonly used values should I order?
--Any advice on how to proceed would be greatly appreciated.

“Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.”
H.L. Mencken 1880 - 1956

Best Regards
Clear Ether

[budm]

Re: LG Flatron W2252TQ-TF P.S. Board

ZD101 is connected in parallel with the Source resistor of the power MOSFET that drive the tansformer for the 5V and the 22V power supply. It will show as short because the Source resistor is less than 1 Ohm. Right now the the 22v power supply section is working which means the transformer drive circuits in the primary side is working. You need to check rectifier diodes for the 5V section to see if they are OK. The picture of the whole bottom side of the board is kind of dark, not enough for me to trace out the 5V power supply section. You can disconnect the main board from the power supply board to see if the 5V will go up.