[Stratmando]

A friend gave me a Computer that was supposedly Lightning or surge Damaged?
He tested power supply with a tester, Tested Good. I tried a good switch to mother board(front power switch), no response, Have not seen an onboard fuse.
What is a good test, to see where power is stopping? Motherboard/Processor?
Any ideas? Thanks

[Scleros]

What is a good test, to see where power is stopping?

For ATX power supplies, if the power supply is not turning on when connected to the motherboard and the front button is pushed, the motherboard's circuitry isn't pulling PS_ON (Pin 14, green) of the power supply connector to low (ground) to turn the power supply on or the front button is bad. Another possibility is the board isn't recognizing the PWR_OK signal (Pin 8, +5 V, gray) from the power supply or detects another problem and is shutting the power supply back down. Does the supply "hiccup" when the power button is pushed?

Since the power supply tester said power supply was good, the motherboard is probably bad. ATX specifications are available at FormFactors.org and give timing delays and acceptable value ranges for the signals.

[Stratmando]

Hey Thanks, So if I jumped pin 14(PS_ON) to pin 15(Gnd)that should power up Power supply? Might the computer power on? I understand there is a transistor that switches pin 14 to ground. Should be able to follow the trace from 14 to the transistor, if trace is on back side of board, will likely replace.
I found a replacement board for under $200, or $100 to swap old board. The processor is under $100. Thanks for your help.
Do you suggest new Motherboard and existing processor? Then, a New processor if it still doesn't power up?

Here's the Motherboard:
http://www.blueraven.com/us/service-...oePartNo=W5553

Here's the Processor:
http://www.blueraven.com/us/service-...Name=Processor

Oh yeah, it doesn't Hiccup, Nothing. Take Care

[Scleros]

if I jumped pin 14(PS_ON) to pin 15(Gnd)that should power up Power supply?

Yes, until you remove the jumper.

Might the computer power on?

So long as the jumper is held. Once the jumper is removed, the motherboard's circuity is still in the off state turning the power supply back off.

Do you suggest new Motherboard and existing processor?

Compare the cost of a replacement board for existing processor and memory plus the cost of a replacement processor in case that is determined damaged as well once the replacement board is installed, to the cost of a new current board, processor, memory, and time value to reinstall Windows/software/etc.

I typically have a compatible known good board or processor floating around the determine what is actually needed. Barring that, I usually go the route of new board, processor, and memory and consider it an opportunity to upgrade to latest tech, get a 3 year warranty on everything, and not worry about what other ghosts may be lurking. I wouldn't do $200 on surplus aging tech if I could get new tech for $300-$400. I haven't had the best luck with replacement boards pulled from salvaged computers. If you can find a genuinely new replacement board that has just been sitting in someone's stock since the computer was current, that's a safer deal.

[Stratmando]

While on the subject of power supplies, it seems the Power supply tester must have 14 jumped internally in the tester, and pin 8(PS OK)goes to the good or fault indicator on tester?
Scleros, Thanks again.
Here is the pinout in color, I'm sure you have this:
http://www.helpwithpcs.com/courses/p...nc-pinouts.htm

[Scleros]

...and pin 8(PS OK)goes to the good or fault indicator on tester?

I think it would depend on how smart the tester is, but that is the case with my $10 Antec tester although it looks like other signals are taken into account as well. The trace from 8 eventually makes it way to the green LED. Note, if you ever get a budget tester, don't hook a supply up to the tester and then answer the phone, the tester may melt when the load power resistors heat up. :rolleyes: