85Views10Replies

Author Options:

Turning On an old PSU - When all failed Answered

Hey there !

I have this old psu that came from an HP NetServer, Delta DPS-350EB, an old AT form psu and i just can't get it to turn on manually.

I have a Dark Blue wire bundled with a ground that's coming from a ''pwr ON'' labeled pin in the psu, when shorted the psu come alive for 2 seconds then shut back off.

I tried putting a load (CD drive) on the 5v with no success. Tried shorting all the other cable (those that i know aren't 3v, 5v, 12v + or -) with no succes.

Anyone got an idea?

Thanks

Bill


Discussions

0
None
wbzial

5 years ago

I finally got it. As mentioned in this thread, it needed a 10w 1ohm resistor to get it to start
Thanks a lot guys

0
None
mpilchfamily

5 years ago

If it's an old AT PSU that doesn't have a switch on it and you have crossed the wires and get nothing than the PSU is dead. With as old as it is the capacitors in there are probably good and dry and causing all sorts of problems.

Here is a good idea for you. Scrap it for what good parts you can get from it. There is no telling what issues it may have above and beyond the capacitors. But you could try replacing them.

0
None
wbzialmpilchfamily

Reply 5 years ago

I just pulled the motherboard and plugged the PS1 & PS2 connector to it and the PSU started FINE.

I'm on the right track, i read somewhere that it need a minimum of 1A on the 12v & 5v. Might be what i'm missing....

0
None
mpilchfamilywbzial

Reply 5 years ago

If it's an ATX PSU then you need to be looking at the 24 pin connector that connects to the motherboard. You need to short the green wire with one of the black ground wires to turn it on.

0
None
wbzialmpilchfamily

Reply 5 years ago

As per the first post, it's an old AT form psu, not ATX.

0
None
mpilchfamilywbzial

Reply 5 years ago

Stick a power resistor on the 5V rail. Short a 5V (red wire) to ground (black wire). The old AT PSUs need to have a load on the 5V rail to turn on.

0
None
wbzialmpilchfamily

Reply 5 years ago

I tried a simple resistor on 5v with no success. I also tried LED, no success either. Keep em coming, i'm trying them all!!!

Like i said in previous post, once PS1 & PS2 are plugged in the motherboard, it start. So it has to be about putting a load on 5v but how much?

The label on the PSU mention a minimum load on 5v, i'll try to match that, tho i don't see what i can use to load 1amp on 5v...

0
None
mpilchfamilywbzial

Reply 5 years ago

A simple little resistor isn't going to work. You need a heavy duty ceramic or other wire wound resistors that can handle the power.

To create a 1A load on a 5V rail you'll need a 5 Ohm resistor. Keep in mind that resistor will need to handle 5W. Since 5V multiplied 1A equals 5W. So a little 1/4 watt resistor like the one you've tried before won't handle it and won't give you a 1A load.

0
None
wbzialmpilchfamily

Reply 5 years ago

I took it out of a WORKING server.

It was running when i took it out, no reason that removing the cover ruined it.

I just didn't find the way of starting it.

0
None
mpilchfamilywbzial

Reply 5 years ago

You know what? Pictures would be very helpful so we know what we are dealing with.