computer power supply

[fkuk]

i have a compaq computer power supply i am trying to turn it on without the motherboard
so far i have gotten nowear with turning it on

i ahev goten it to turn on for one secod then turn off (but because i have tried so many comonations i can not remember how i did that

the plug has 24pins and when there is nothing connected the green wire pin 9 has 5.04volts on it pin 8 does not exist

how do i turn it on

 

[ghostman11]

connect the green wire with GND (black)

 

[fkuk]

the voltages before connecting green (pin 9) to black
green (pin9) = 5volts
pink (pin11) = 3.33volts
everything else 0v

when i connect green (pin9) to ground
pink (pin9) = -1.67v ish
grey (pin7) = -5.04v
also a funky smell comes from inside the box
so i belive this is not the correct thing to do

 

[ghostman11]

i was assuming it was a ATX unit, looks like it isnt, have a look here How to Convert a Computer ATX Power Supply to a Lab Power Supply (with video) - wikiHow. you need to locate the power on wire and ground it, do you have a model number for the psu?

 

[jimlovell777]

Computer power supplies REQUIRE a load, you cannot simply power one up without having some sort of load. Most hobbyists connect a power resistor across the 12V lines to provide this load. Google it.

 

[fkuk]

it is a
compaq
model: ps 7231 6cf
part no is 243890-001

also i have tried it with a cd drive connected to it using the molex connector

 

[ghostman11]

not all psu's require a load! i run a few without any load at start up. from what i can gather the compaq is a special case and isnt standard wireing. i have a feeling you have to tie the white wire high. but i cant find anything clear on it

 

[ghostman11]

have a look on here it might help you identify wich one it is ATX, BTX, WTX and other power supply cables connectors pinouts listing @ pinouts.ru

 

[fkuk]

ive looked on the website i am trying to match the pin 8 because that one is missing and i cant find it i will take a picture of my connector and post it here

 

[fkuk]

ps pictures by fkuk - Photobucket

 

[fkuk]

**broken link removed**

 

[fkuk]

**broken link removed**
**broken link removed**

 

[fkuk]

here are the pictures and i looked again but i can not match it with one on the site

 

[ghostman11]

my feeling is tie the white to 5+ plus its just a guess, i only use ATX psu's try shorting the white wire and 5+ briefly and see what happens. but be careful you dont make magic smoke

 

[fkuk]

when i connect the white to green the fan twitches then stops
on the white molex connector thr orange (i belive it is ment to be yellow in other computers) goes to 10V and then drops down to 0V

the red on the molex goes to 0.38v and then goes back to 0V

but the thing is there is no smoke or bad smell

 

[Reloadron]

I am going to venture a guess this is not a standard ATX form factor pin out. Even the color scheme is weird. Frequently some server and workstations deviate but generally the colors remain uniform.


I did find the attached image in a Compaq service manual and it is really different including how the pin numbers are designated. Unfortunately it doesn't have a color code scheme. The namiing conventions are peculiar too. Anyway, it may be of some help.

Ron

 

[fkuk]

i have discorverd somehting strange

when you connect the grey wire to the brown wire
then connect and disconnect the green and the white the psu starts up for half a second if you connect and disconnect repeartedly the psu seems to turn on (if you keep up the connection and disconnection)
it even powers up the cd drive that i have connected to the molex but you have to (conect and disconnect ) really fast for that

 

[Reloadron]

This connector pin out is likely what you have. Also my read is that to start a Compaq PSU you need to present a logic high (opposite of ATX form factor) on the PWR ON/STBY line. Pin 17 should be the 5 V Aux and always on with 5 V. Pin 8 should be the PWR ON pin. So a jumper between pins 17 and 8 should start the thing.

I am not 100% on this so your call as to trying it.

Ron

 

[fkuk]

i think the psu has bit the dust i was trying different combanations of my discovery above when there was a spark and now the psu keeps ticking at me

it could be anything inside

it could be a solder joint has broken or shorted because before when i connect some pins together with would tick in the exact same way as it is now

so could you tell me for future refference what type of power supply to buy so it works straight of the bat no messign around

 

[fkuk]

This connector pin out is likely what you have. Also my read is that to start a Compaq PSU you need to present a logic high (opposite of ATX form factor) on the PWR ON/STBY line. Pin 17 should be the 5 V Aux and always on with 5 V. Pin 8 should be the PWR ON pin. So a jumper between pins 17 and 8 should start the thing.

I am not 100% on this so your call as to trying it.

Ron

in 8 does not exist of my connector