How to use a standard atx ps on a compaq mobo

**tastyratz** · 06-11-2005, 10:33 AM

ok well I did tons of searching and wasnt able to find anything on this. I purchased a compaq ipaq off ebay for a rediculously cheap price. you can get used whole systems with a 733 for about 100$ or so. This is a good midrange system for people on the cheap. complete with case and all you need except for a power supply. Unfortuanately, compaq being seperated from the crowd, they used a non standard 14 pin style of atx. After awhile of searching the net I decided to call hp cust. support. After awhile of convincing I managed to squeeze the pinout from someone!! this is good for future reference if anyone needs it...
compaq 90w 14 pin ipaq power supply
1 3.3v orange
2. +5v red
3. rtn black
4. +5v red
5. rtn black
6. +5v red
7. rtn black
8. +3.3v orange
9. -12v blue
10. fan off gray
11. on/ stby green
12. +5v aux purple
13. rtn black
14. +12v yellow

this is a standard atx pinout
1 +3.3Vdc Orange
2 +3.3Vdc Orange
3 GND Black
4 +5Vdc Red
5 GND Black
6 +5Vdc Red
7 GND Black
8 PWR-OK Gray
9 +5Vdc
VSB
standby Voltage Purple
10 +12Vdc Yellow
11 +3.3Vdc Orange
{brown is 3.3Vdc
sense]
12 -12Vdc Blue
13 GND Black
14 PS-ON Green
15 GND Black
16 GND Black
17 GND Black
18 -5Vdc White
19 +5Vdc Red
20 +5Vdc Red

First column is compaq pin#, second is atx pin #. Use this guide to match up the pins from the power supply on your atx, to the one on the compaq. this * should* work fine.
1 - 1
2 - 6
3 - gnd
4 - 4
5 - gnd
6 - 19
7 - gnd
8 - 2
9 - 12
10 - ??
11 - 14
12 - 20
13 - gnd
14 - 10

the only pin that doesnt match up is pin 10 which is fan off. I have a feeling everything will work fine without that pin so if anyone needs to follow my lead there ya go :-) Enjoy your cheaper complete carpcs :-)

**tastyratz** · 06-14-2005, 08:08 PM

ok looks like that didnt quite work the way I wanted it too. I tried this and the computer will just not boot now from the dc-dc power supply. I know its putting out voltage in the pins i tested it as positive. I connected everything but the "fan off" pin. I tried attaching that to ground, ps ok, and 3.3 . I know power is getting to the compaq because I can hear the thing clicking away somewhere (not the hard drive or anywhere else... someplace on the mobo. anyone have any ideas on what to do??

**tastyratz** · 06-19-2005, 07:53 PM

any ideas? anyone?

**Demonic_Chicken** · 08-16-2009, 04:12 AM

This is an Epic freakin necropost, but I had to tell someone, because it seems that no one on the internet has published their solution to this.

So what you have done is fine, but make these changes:

Take the ENABLE wire from the modern ATX power supply, don't connect it to the connector, connect it to the Gnd (black). You'll want to put some sort of switch here, because the PC will run at full power despite not being ON. ( I don't know why, blame compaq and their retarded standards).

I also connected the FAN off pin (pin 10 by your numbering) to +3.3 volts.
This made the CPU fan run at full blast. I figure that full blast is better than OFF, since it wont over heat this way. I bet you could vary the voltage to change the speed, but I dunno.

Before I made these changes, I had the same situation as you:

Motherboard lights are on, pushing power causes a really brief power up, then returns to lights on. the hard drive light was ON constantly. With the Fan connected to 3.3v, the fan was also blowing at full power. but no start up.

Removing the ATX supply's enable wire from the motherboard connector, and just connecting it to ground allowed the PC to boot when the front power button was pushed.

SO yeah, If there is anyone else out there in 2009 and beyond, messing around with an antique compaq computer, there you go. I was fixing it for a friend, though since the supply is ATX, and not small profile like the original, We are just gonna swap the drive to something else. I just wanted to beat this stupid proprietary bull****. I'd be nice to get some props, but I get the feeling that this forum has been abandoned for years. This will probably just sit around till the end of time.

maybe some one will google it, like I did.

**eroticaxp** · 01-07-2010, 09:02 AM

Yes it is a very necropost. As far as the admins might be concerned you are a moron for posting in this thread. As far as i am concerned...i kinda owe you a beer or something. Im gonna get to work on this thing right away. I am that one person at the end of times that wants to mess around with a Compaq Deskpro EN. So...yeah...i sure hope this helps so i can get the damn thing working. Thank you very much.