>I opened the case and measured a pin labeled +12V and found only 2V when the
>power switch is held down, and goes to 0V when released.

>The front panel power switch itself is functional -- I short out the two
>contact points with a wire and got the same 2V as above.

>This could mean the circuit that controls the main power (probably a power
>transistor) is bad, or there is a short circuit dragging down the voltage.
>Since there is no smoke when I held down the switch, I'm hopeful it's the
>first case.

>The power supply (external adapter) is 12V 4A. The wires leading to the
>front panel power switch is very thin, and the switch itself is a push
>buttom with momentary contact. So I figure the power switch is not what's
>directly turning on the power; it must be controlling a semiconductor that
>turns on the full 12V 4A to the entire unit. However, I did not find any
>power semi-conductor that looks like it can switch on/off 4A of current.
>Here's a photo of the circuit board:

>http://www.smugmug.com/gallery/6159236_bYvW4/1/388058044_TTcnS
>(put mouse on the photo and click "original" to see full resolution)

>Any idea which chip/transistor controls the 12V 4A to the rest of the
>system?

>To further debug the problem, I need a circuit diagram. Any idea where/how
>to get a circuit diagram of a viewsonic monitor? I looked on viewsonic's web
>site and the phase "cicruit diagram" or "repair manual" returned zero hit.

>Without circuit diagram, the only thing I can think of is to solder a wire
>directly from the input 12V DC to one of the +12V lead. If this works, it
>means the unit cannot be turn on/off via the front panel switch. If it
>doesn't work, it may generate some smoke...