I was thinking of re-purposing an old HP/Compaq desktop PSU for use on a project that needs 12V, but I'm having trouble getting the PSU to start up. I've used ATX supplies before, and have therefore had to short the POWER_ON connection to get them to start, but this unit seems different.
For starters, instead of a 20- or 24-pin Molex, this one has a 10-pin and an 8-pin Molex.
So connector one looks straight forward enough - a bunch of grounds, a pair of 5v red and a pair of 12v yellow:
red black black yellow red black black yellow
Connector two looks like the cleverer one:
blue yellow purple green black orange n/c n/c n/c black
Now, if I power the thing up connected to a motherboard, I get pretty much what I expect from the ATX documentation I've seen, which is: Blue: -12V Orange: +3.3V Yellow: +12v Purple: +5v (STANDBY - this is always on) Green: 0.06v (POWER_ON)
However, disconnected from the motherboard, when I manually short POWER_ON to GND, I get a blip of power, but it drops straight back down to zero.
The PSU has the following label:
COMPAQ COMPUTER CORPORATION Model: HP-L1520F3P Part Number: 308446-001 Spare Number: 308619-001
It's apparently a "308446-001 HP Compaq power supply 150 Watt for Evo D530UST ultra slim desktop PC" and this is what it looks like.