Electrical storm damage?

[Odyssey]

Following an electrical storm, a computer which was unfortunately plugged in at the time, now doesn't start up. The on/off switch may also be faulty.

Tested the PSU with a PSU tester and it shows to be OK.

When it is first plugged in, the cpu fan comes on for 2-3 seconds, then goes off. Occasionally this behaviour can be duplicated using the off/on switch.

No beep at all.

CPU or mobo fried?

 

[Odyssey]

P.S., I assume that the reset wires need to be moved to the power posts, or might it work as normally wired?

 

[edfair]

Yeah, move the connector from the reset pins to the power pins. And put a note on the front of the machine so people don't wear their finger out.

Sorry about not mentioning the RAM. It was buried down on the list and got overlooked in the other stuff.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[BadBigBen]

Ed, about the RAM, well even I have not seen that, I am used to PC's beeping when the RAM is damaged (not turn off)...



Ben
"If it works don't fix it! If it doesn't use a sledgehammer..."
How to ask a question, when posting them to a professional forum.
Only ask questions with yes/no answers if you want "yes" or "no"

 

[edfair]

I remember a couple over the years. Don't recall the circumstances but it happens.

On some earlier stuff I worked on the processor kept on keeping on but when it branched out to a subroutine it came back to a different place until it locked up in a tight loop. That was on stuff with separate address and data and nothing multiplexed, which helped considerably.

In any case, the fix is by a stroke of luck. there is no diagnostic that I've found that will show what is happening.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[DTracy]

What he could do is jump the green wire to the black wire on the P4 plug from PSU to the motherboard. Then use the power switch on the power supply to turn the computer on and off.

Might work...

David

 

[gbaughma]

Ummmm... Odyssey... have you put a DVOM across the wires for the switch to verify that it is in fact bad?

Switches are pretty simple things.....



Just my 2¢

"What the captain doesn't realize is that we've secretly replaced his Dilithium Crystals with new Folger's Crystals."

--Greg

http://parallel.tzo.com

 

[Odyssey]

Errrrr.... What is a DVOM again? Sorry you are a little over my head.

My diagnostics at this point were to reassemble the computer down to a test by shorting the power connectors to be sure that it would start, then connecting all the front panel leads. Pressing the power on switch on the front of the computer resulted in nothing. Disconnected the switch and jumped it again to start it.

David's "might work" makes me nervous. Any other thoughts on this anyone?

 

[edfair]

Digital Volt-Ohm-Milliammeter. The ones where you can mislocate the decimal points but you don't have to interpolate on the log scales. In this case an analog meter would probably be better.

David's might work is really a will work, but you lose the shutdown capability from the front. And some PS units don't have switches. But you also get a temporarily unstable power output between the time the buzzer starts until the switching voltage is up to snuff.

Put the reset switch connectors on the power up pins and see if will crank it up. Assuming you have a reset switch.

Sometimes the power on switch is more than just the switch. Have you pulled the front cover to see what you are dealing with. I'm thinking something like the emachines switchblock, possibly.

Ed Fair
Give the wrong symptoms, get the wrong solutions.