Any experience with Dell PSUs?

Gutter · 05-11-2004, 02:13 PM

I'm working on a non-mp3car related project where I need the motherboard to come on when power is applied. Typically, the easiest way to accomplish this is to short the PSON wire (pin 11) to a ground wire (pin 12) coming from the PSU.

But silly old Dell and their proprietary PSUs are causing me troubles. I found the PSON pin and I can make the power supply come on with power is applied, but the motherboard won't turn on. Any thoughts, theories, or other speculation as to why this might be?

Pinouts:

1 +5 VDC (red)
2 Common (black)
3 +5 VDC (red)
4 Common (black)
5 PWRGOOD1 (orange)
6 +5 VFP (purple)
7 +12 VDC (yellow)
8 –12 VDC (blue)
9 Common (black)
10 Common (black)
11 PSON#2 (brown)
12 Common (black)
13 Common (black)
14 Common (black)
15 –5 VDC (white)
16 +5 VDC (red)
17 +5 VDC (red)
18 +5 VDC (red)
19 Not connected
20 +5 VDC (red)

1 Pin 5 — PWRGOOD is a status signal generated by the power supply to notify the system that the DC operating voltages are within the ranges required for proper system operation.

2 Pin 11 — PSON# is activated by pressing and releasing the power button while the power supply is in standby state. Activating PSON# connects the power supply’s PSON# input to ground, thereby switching the power supply to full-on condition.

Enforcer · 05-11-2004, 02:27 PM

As you have noticed, DELL are a pain in the <insert derogatory word of your choice here> with their 'special' PSU's. Do a search on

I belive I once came across a site that sold or described how to use a normal ATX with a DELL.

Gutter · 05-11-2004, 02:34 PM

Well I just discovered that the motherboard still needs that momentary short between the pwrswtch pins. AWESOMETASTICLES! I've seen articles like what you're talking about, but it now looks like I've once again been defeated by the almighty Dell EE Retard Brigade.

I guess I'll just break down and buy an epia or something. Feh.

Enforcer · 05-11-2004, 02:54 PM

Don't fret it I have a compaq EN SFF, which also has a proprietry PSU, I also tried matching the wiring but no luck. So I am replacing with a MicroATX board and doing a custom fit rather than just plonking th PC in as I have now.

Pokey · 05-13-2004, 08:12 PM

I am adding this ATX pinout below, just so someone doenst think the one above might be an ATX pinout, i almost did. I did a search on this site for the PSON wiring and came up with this thread.

ATX Power Connector
Pinout

Please note that this connector's pins are numbered oddly - not in the normal manner Instead it is numbered like the odd-ball Sub-d connector. Probably someone who had not laid out many PCBs did this. (A normal approach would have been to number it counterclockwise looking at the sockets or clockwise looking at the pins)

Pin Signal Wire Color
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