Plz help: Power supply failures

[some1]

hello all,
I have a year old Dell Dimension 4600 2.4G 256k ram 80Gb HD in my lab

last week, I shut it down properly, but the next day I could not
turn the computer on..I tried different sockets, switched power
cables, confirmed that the cables I was switching were working. but nothing
So I removed Power Supply to see any obvious signs of death, but found no such signs. Looking at the motherboard,I can see one green light onwhen power is plugged in...but unable to start the PC. I have heard no fan noises, have had no issues with power prior to this..

Just to check if power supply is working, I exchanged powers supply unit with another working dell computer (exactly same configuration)..but on exchanging the PSUs also both the computers did not start. Now to add to it the working computer does not start even with its own power supply. So basically both the computers are not starting anymore with their respective power supplies(except for that green light turning on)..I am totally puzzled whats happening here..

Guys plz help me, I suppose I have screwed 2 lab computers:(
I appreciate your help very much.

Thanks
SM

[Mick_D]

Please clarify. Did you take the PSU from your non working computer and place it in the working computer? Or did you replace the PSU from the working computer in the non working computer?

[some1]

We did both. First PSU from non working computer and placed it in the working computer.. that didnt work. then I put the PSU from the working computer in the non working computer and it dint work too.
Finally I replaced my PSUs to their original comps. But now the working computer is also not starting...

[Mick_D]

OUCH! I was afraid you did that. You should have placed the good PSU in the non working computer. If the bad PSU was producing erratic voltage output you may have very fried to mobos. Do you have access to a voltmeter or another good PSU?
CAUTION! If it's a non Dell PSU you have as a spare, be sure the power connector matches the Dell. Compare the color of the wires in the original 20 power connector to the replacement 20 pin power connector before connecting to live voltage.

[computernerd]

i bet that the power supply from the bad pc fried the stuff inside the good pc

[mary13]

My Power supply has stopped working. I need a new power supply, Model no MXM-145TF1, can anyone help and advise where to obtain this.

[Sylvander]

I've seen it said that PSU's have an internal fuse.
Your faulty M/B may have blown the fuse on both of these PSU's.

Download a copy of my diagnostic flowcharts from here
www.erniek.eclipse.co.uk/downloads/sylvanderdiags.zip
and print them to leaf through.
Begin on the STARTUP chart.
You should end up on the ATX Power Supply chart.

Powering an ATX PSU without a motherboard [to test the PSU] (http://www.virtual-hideout.net/guides/atx_psu_mods/index.shtml)

ATX PSU info (http://www.compute-aid.com/atxspec.html)

More ATX PSU info (http://freespace.virgin.net/matt.waite/resource/psu/atxpsu.htm)

Lots of links and info on PSU's (http://www.epanorama.net/links/psu_computer.html)

[Sylvander]

You should start your own thread Mary, and welcome to the PC Guide. :) :D