Will bad switch kill "power good" signal

I'm working on a system with no power, no spinning fans, no POST beep(s).The green LED is lite on the mobo.The owner says it was hit with a lightning spike during a storm while she was online.
The modem is slightly melted (which I pulled) Its a Dell Dimension 8200. The obvious choice is a dead PSU (meter shows no correct voltages). The funny thing is...the owner already replaced the PSU. Its a DELL, which are often proprietory, and although the "new" PSU doesn't say "DELL" (like the old one did) she cliams she got it from the Dell store.

It wouldn't be the first time I installed a brand new part that was bad (which REALLY confuses the troubleshooting process). But theres one little thing that has me puzzled. The power button on the case...usually you feel a definate "click" when you push it. This one doesn't. I once had a bad power button that I had to replace (which is hard to do without buying a whole new case).

This brings me to my point...if the power botton doesn't make proper contact, will the mobo still signal the PSU (via the "PS_ON", "Power_Good" or "+5VSB standby" lines) to send power?

My next step will be to remove the PSU, jump start it (placing a "dummy" load on it), then reading the voltages. But maybe I should just go get a Dell compatible PSU (but they aren't returnable, so I want to be sure first).

If a bad power button is (or could be) the problem, is there a way to bypass it ...basically shorting it to signal the mobo to start the PSU?

 

Seein as that thing was hit by lightning - I'd say it is fried.. that modem got the brunt of the juice, but I'd say the mobo got it also. But to continue your trouble shooting try this: trace the switch from the front case to the mobo..(I doubt you'll find the mobo documentation with the pin outs).. in most PCs I have assembled that switch connects 2 posts on the mobo. Pull that connector off. Now what you have to do is momentarily make contact between those to boot. I use a jumper, clipped in hemostats - push it on for a second and pull it off.

 

If you want to test the PSU, find the green wire on the ATX-type connector (the one that goes to the mobo) and short it with one of the black ones.

This is how you do it for most normal ATX supplies, but I'm not sure about a dell one.

 

Hi
I noticed you are dealing with a DELL
I have a DELL that I had to put together, I got a lot of help here

http://forums.us.dell.com/supportforums/

DELL Documentation here--

http://support.dell.com/support/top...duct_support_hub?c=us&cs=19&l=en&s=dhs&~ck=mn

If you want to post at the forum, you have to register, but the guys there, are like the guys here, except at the Dell forum they specifically deal with DELLs, they are all users helping users. I had a box of parts, no case, just innards,I supplied the "parts list", and the guys there nailed my machine within 12 hours, with links for assembly for the DELL Doc. site
Be advised though, the Forum is at DELL, but it IS NOT manned by DELL

The 2nd link is DELL support, this is where you will find all the schematics for a DELL, including power values and mobo plug map.

Good Luck

P.S.< I didn't even know the model, age, etc., all I knew was that it was a DELL

 

Shorting the green wire on the main ATX connecter to a black ground wire will turn on the PSU ( some times you half to hold it shorted for the PSU to work )

 

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