Dell W3000 power light on. No video. No backlights

[Lumberjack777]

I'm trying to repair this Dell W3000 for an organization. The original PSU was fried. So I bought one off eBay. The seller assures me it was pulled from a working unit. I'm not so sure.

My initial test results are as follows. With the PSU isolated and not connected to the logic board. The fuse is good. The main filter capacitor shows 170v DC. But when I test the power IC located at IC201 (right side middle) the VCC shows zero volts.

When I test the 2 outputs from the PSU...

First output
18v = 13.56-15.04 (fluctuating)
5v = 4.87-5.15 (fluctuating)
12v = 0

Second output
12v = 0
24v = 0

This PSU definitely appears to be faulty to me. My only concern is that this design has some sort of reset controller or whatever on the logic board that fires up the entire PSU.

These results shows a faulty PSU. Right? Even when not connected to the logic board, and no video input.

So where do I go from here?

P.S. Sorry if the quality of the pics isn't great. I have an original Epson 850Z with a whopping 2.1 megapixels! Thanks

*******UPDATE******** After connecting the PSU to the logic board the voltages are there. Now I suspect a component on the logic board. Some sort of reset controller. But I don't know where it's located

[Lumberjack777]

Re: Dell W3000 power light on. No video. No backlights

Now this is getting interesting. After examining the main board it looks like a capacitor was added by the manufacturer after the board was originally manufactured. Circled in red. I'm 99% sure now the no video/backlights is coming from the main board. I just don't know how to test it, or where to check.