Troubleshooting no power

[sbrambo]

I have an older server with an Intel SE7501HG2 board that won't turn on. It was restarted this morning and after it powered down it stayed down, with no lights on the front of the box. Plugged the 24 pin plug from the PSU into a Thermaltake Dr. Power tester while everything else was still connected to the PSU and all the drives started spinning and the PSU fan started running. Plugged back into motherboard and get nothing.

I tried putting a jumper across the Power Switch pins on the motherboard and still get nothing.

Anybody got any other ideas for the next steps I should try?

Thanks,
Scott

 

[Harvey]

Something could be shorting out the PSU.

1. Try unplugging and reseating the vid card RAM, and anything else plugged into the motherboard.

2. Try plugging in another vid card.

3. Remove all but one stick of RAM. If the machine doesn't start, try another stick.

4. Test the motherboard with another known good PSU. You tested the PSU as far as the Thermaltake tester went, but several of the user comments for this tester on Newegg suggest that the results are unreliable and could give positive results for a PSU that won't actually work with a motherboard.

Good luck.

 

[sbrambo]

The video is on the motherboard. Nothing changed after reseating everything. Tried to start with everything unnecessary disconnected just to see if I got any signs of life, but got nothing.

Don't have another power supply to try on it. I kinda had the feeling that everything spun up when I connected it to the PSU tester that the motherboard isn't making the power connection you get with the paperclip across the green and black wire test I've read about (which is mostly all that tester is doing, really.)

Any other suggestions?

Thanks,
Scott

 

[Harvey]

We already established that results from the Thermaltake tester may be unreliable. The only way to know if it's the board or the supply is to connect the board to another supply and/or to connect the supply to another real computer. If you can't borrow one from a friend, you might buy one from a place that will allow you to return it if that's not the problem.

You don't have to install the test supply in the machine. You can simply lay it down on its side on a table or the floor, put the test supply next to it, connect all the wires, and hit the start button. Either it will start to spin up, or it won't.

The other option would be to try your supply on another real machine, instead of the Thermaltake tester.

Again, good luck.

 

[VirtualLarry]

Something similar happened to my HTPC. For a while, if the power went or or something, the PSU didn't want to start up. Sometimes I had unplug it, then plug it in again, before it would power up. I decommisioned that HTPC, but while I had it on the test bench, I couldn't get it to power up any more at all.

I put the mobo and rest of the guts into another micro-ATX enclosure with a PSU, and it all powered up again just fine. So it was the PSU in the old enclosure, which had run 24/7 for a number of years.

 

[davC]

When the PSU is plugged into the mobo and off, what DC reading do you get on the purple wire of the main motherboard connector?

 

[sbrambo]

I ended up ordering a new PSU as well as a Dr. Tester 2 by Thermaltake. It showed the old PSU as indeed bad and the new PSU tested fine. Put it all back together and it all started right up.

Thanks for all the help guys.
Scott