Thread: Using an older Dell power supply for props

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I've been posting about how to power a wiper motor, and I was advised to try a computer power supply. I read Scary Terry's pages regarding this subject, and pulled out an old forgotten computer's power supply to try it out.

It's an old Dell computer with an HP-145SNH power supply putting out 18 amps at 5 volts and 3 amps at 12 volts. When I compared it to Scary Terry's diagram, I found that it didn't match, not even a little bit! There was a different arrangement and numbers of colors, and no green wire for the all-important PS ON.

After researching and trying to find pinout documentation, I discovered that older (1996-2000) Dell PS's use a non-standard and infrequently documented wiring pinout. And since it seems everyone and their grandmother has an old Dell nowadays, it's very likely someone might want to use one of these power supply for their Halloween prop or wiper motor.

Here's a good page to show you the *old* Dell standard: (they use standard supplies now.)

InformIT: PC Repair and Maintenance: In-depth Look at Power Supply > Motherboard Power Connectors

It's about halfway down. If you Google Scary Terry's instructions for using PC power supplies, and use the above site to adapt Scarry Terry's instructions for shorting the PS ON and GND pins, and adding a load resistor to the 5v pin if needed, it should work fine.

In case the page someday disappears:

Table 3.8 Dell Proprietary (Nonstandard) ATX Main Power Connector Pinout
(Wire Side View)

Pin Signal Color

1 +5v Red
2 Gnd Black
3 +5v Red
4 Gnd Black
5 Power_Good Orange
6 +5VSB (Standby) Purple
7 +12v Yellow
8 –12v Blue
9 Gnd Black
10 Gnd Black
11 PS_On Gray
12 Gnd Black
13 Gnd Black
14 Gnd Black
15 –5v White
16 +5v Red
17 +5v Red
18 +5v Red
19 KEY (blank) — [unused/brown on mine]
20 Red +5v

Table 3.9 Dell Proprietary (Nonstandard) ATX Auxiliary Power Connector Pinout

Pin Signal Color

1 Gnd Black
2 Gnd Black
3 Gnd Black
4 +3.3 Blue/White
5 +3.3 Blue/White
6 +3.3 Blue/White

PS. I have found that my Dell Power Supply works fine with only pins 11 and 12 connected. It may still be advisable to provide the load resistor between pins 1 and 2, but doesn't seem necessary. Please correct me if I am wrong.

Nice of you to pass along your new found info!

MsM