Jumping PSU problem

G-Dubs · 15 Sep 2010 at 21:12

Just tried to jump start a psu to make a 12v supply for some leak testing i'm doing and seem to have a bit of a problem

Never done it before so might be user error.

It's an old 20 pin psu but instructions on the old internet (several sources) are to find the green wire and short it to any black wire.

When I do it the psu fires for a 1-2 seconds then stops. Give it a few seconds and it will work again but same thing happens

PSU worked fine when taken out of the PC a few months back

Any suggestions???

RJC · 15 Sep 2010 at 21:14

Have you anything connected to the PSU?

Also double check the connection of the link.

G-Dubs · 15 Sep 2010 at 21:18

Yeah I put a 120mm fan onto a molex to add some load. It spins up, the leds light up, as does the fan on the psu, then it all just stops. no hissing or burning or anything, just stops

vsmora · 16 Sep 2010 at 02:55

Not enough load I reckon, add something more.

MikeHunt79 · 16 Sep 2010 at 03:06

Some chunky 50w resistors can make a nice dummy load, or some 12v car headlight bulbs, these pull around 50w - 60w each.

Essexraptor · 16 Sep 2010 at 05:25

The method you have outlined is normally used to check a PSU is not "cream crackered" and normally has a case fan connected via molex.

I take it you just want to run the pump from the PSU?

G-Dubs · 16 Sep 2010 at 09:44

yeah just want to use it as a 12v power source for leak testing. haven,t tried it with the pump yet but i guess its not going to offer much resistive load up either

MikeHunt79 · 16 Sep 2010 at 14:00

What wattage is your pump? I've just used a 12v wall plug in the past to power a pump.

G-Dubs · 16 Sep 2010 at 16:02

vsmora · 17 Sep 2010 at 06:46

An 18W pump should be enough to dummy-load most PSUs under 450W. Some normal office desktop PCs can approach that low when idling.