Hope somebody can help.

I have aquired a replacement to my ailing PC, but sorting it out for a new OS it seems the PSU has died.

The PC is a dell precision 390, with what seems to be a small profile ATX PSU 24 pin main connector with the 12v 4 pin processor power connector, now if anyone has a spare psu that is at least 400W that i could borrow to prove if it is Motherboard or PSU fail i would appreciate it.

Thanks

Guy

hi guy,

if you cannot get one you could possibly use a multimeter to check the correct voltages on the 24 pin connector.

search google for the schematics of your particular model but heres an example...





Most cpu units and their colours reprisent the same voltages but not all so best to check your particular model to be on the safe side.

Yes I cold do that, but i'm not 100% if one of the sense wires is the fault, and as far as i can tell the PSU won't output all rails unless it's given the soft start input, it's like the PC is locked into standby/hibernate. So the PSU is in an offline state, i'll diss the conn from the board and see what i get on the 5 and 12v rails, if down or no O/P i'l assume it's either in standby or bust.

Thanks so far Ste

Ok further to above, I have 3.3V rail and 5V rail no 12V or -12V pus disconnected from MB won't spin up the fan so could either be in sleep or broken, hence the requirement for a loan unit, could be a fault with either still.

Plug all the other bits into the board.

Memory and keyboard.

I had this a while back and it was the front panel connectors that needed to be in correctly before it spun up.

What age is the MB do you know if it was working prior ?

Sorry I don't have a spare PSU.

If its a brand new MB look for the "RED" jumper on the mother board its a cmos reset in the wrong position.

I call it red, but it could be black.
There was a time Motherboards were shipped out this way.

Hi Mark,

I'll re do the measurements, but i have had the whole thing dissed and replugged so may times. Age 4 years old, was working until a reboot after bios reset, then nowt

A daft one but screw it in to earth it on the tower.
Stranger things have happened.

Check the 24 pin
Make sure none of the pins have been pushed back up.
Thus preventing the contact.
Or tug on each of the cables to the block to make sure there not loose.

I have a tool to check all outputs from psu, also can loan a psu to try
I am sure the Dr can do this for you

Dell may also require its own psu I think the -5v is not used in the 20 pin output

If said tool will bring the PSU out of standby i'd be up for that, then i can check vs standard ATX PSU pinout if they match.

I have heard about Dell being sneaky and using what looks like ATX connectors and calbling colour with non standard config!

Need to prove it first!

You wont get a reading on you 12v rail unless you make a circuit between the green wire and the black one next to it, this is the switch to turn the psu on, your fan should spin up once you do this.

http://www.instructables.com/id/How-to-power-up-an-ATX-Power-Supply-without-a-PC/
Here's a link on how to do it.