help ! pc psu compaq not working, trying to make bench tester

Hi all

do hope somebody can help me out here !

I had an old compaq deskpro that was working but now replaced and needed a 12v 2 amp supply for a project I'm working on.

Pulled the psu out of the pc and found some nice helpful pages on how to get it working stand alone, but I'm just running into dead ends.

The thing is it's a compaq psu (pdp-100 model) all non standard wire colours, orange is brown etc etc, and add to that it has 24 wires not

20 or the 2 split plugs.

I have load (an old hard drive) on the 12 v and have found 2 wires coming out that have voltage on them, tried grounding them both and also tried using a 10hm resistor on them.

tried jumping pretty much every combination of colours to see if i get a sign of life but nothing

putting load on to 5.5v

done a billion web searches with loads of things to do/try but nothing worked.

put it all back together on plugged it back into the pc mother board and dam thing works !!! grrr

wondered if any one has

- either used a compaq psu (non standard) before

- can offer and ideas, maybe by looking at the pcb or checking with a multi meter

- something more drastic, like jump the sensing on the pcb

only thing I can find on the web code wise is the following but it may not be correct !

1 brown +3V 2 brown +3v 3 black com 4 red +5V 5 black com 6 red +5V 7 gray aux com 8 purple ? 9 green +5V aux 10 orange +12V 11 pink +3V aux 12 white/red fan ? 13 brown +3V 14 blue -12V 15 black com 16 white (on stby) 17 black com 18 black com 19 black com 20 brown +3V 21 red +5v 22 red +5v 23 brown 3VRS (small dia wire) 24 white/blue fan sink

any help much appreciated

Ian

Reply to
Mavrick
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Possibly you could measure the voltages on all wires going to the motherboard while the computer is running, then measure them again when you disconnect the PSU from everything. If one wire is at 0V when the computer is running OK, but +5V when the PSU is disconnected, try connecting this wire to ground and see if the PSU starts up. (Maybe it's the purple wire)

... Humphrey

Reply to
Humphrey B. Bear

That's THE way. Lets try it! Oh, shit!!!

(Did you notice that this group has a notion of science in title?)

Have fun.

Stanislaw Slack user from Ulladulla.

Reply to
Stanislaw Flatto

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