Can I use a computer power supply for anything?

Question

I had to get a new case because the "on" switch started randomly powering down my computer. (Yes, Compaq said the switch on my 4 year old Presario was defective, but they can't be replaced .. I need a whole new case!)
Anyway, now I have a redundant 350W power supply. Can I use it for anything other than powering a computer? Like running low voltage lights or model trains or whatever.

Answer 1

Hi there.
A Power Supply 4 years ago would be ATX, which is the newer
type.
To use it, you have to jumper the POWER GOOD feedback wire,
which would normally be controlled by the motherboard (which is now missing ), to one of the 5 Volt RED wires. (( Power good is delayed by the motherboard, until it has 'equalized" and checked a few of its own circuits - it then lets the power supply know that all is well, and full voltage can be applied )
You will have to jumper the POWER ON wire to Ground, ( the Black wires ) to get the unit to turn on.
Search the web for a good wiring diagram of the ATX power supply pin outs.

As someone has stated, there can be control circuitry to monitor the voltage levels, so that spikes and drops from a BRUSH type motor, could cause the power supply to over-react. You can eliminate most of this type of "noise" with capacitors if needed. -- Add a very large capacitor to eliminate the "start" voltage drop, and tiny capacitors to filter brush noise. Always use capacitors much higher than the voltage you are connected to.

On an ATX there is is a 5 volt VSB which is ALWAYS on, but very small current - this is the voltage that powers the mouse the keyboard, and the POWER ON circuits on the motherboard, as well as the Wake on LAN and wake on Modem. An ATX motherboard is ALWAYS alive and can turn " ON" with the clock, the modem ring, the LAN, the mouse or the keyboard.
I would not connect anything to the VSB 5 volts, except an LED indicator thru a resistor about 333 ohms, just to let you know that the power supply has 110V power...

The RED wires are normally +5 Volts, at very high current.
The Orange wires would be +3.3 Volts at very high current,
The YELLOW wires are + 12 Volts.
You will find there is a wire for - 5 and -12 volts, with fairly low
current. Check with your wiring diagram. On the power supply itself, if you are lucky, there is a color code. COMPAQ should have the code on thier website...

You can use the power supply for anything that uses the voltages within the listed AMPERAGES on the different wires...
If you look at some of my other ANSWERS you can see that I wire in 2, 3 or more power supplies together on a typical computer. You just have to make certain that the OUTPUTS do not connect from the different supplies.

12 Volts is a common unit for DC devices, +5 would power most 6 volt devices, and 3.3 volts would power any 2 battery cell device like a walkman or flashlight. By adding a monolithid 780x
power regulator, such as 7806, 7809, for 6 and 9 volts, you could get 6 or 9 volts from the +12. By using a variable power regulator, you could get almost any voltage from 1 volt to 12. ( You would need two resistors, or 1 resistor and variable resistor across the 3 input pins of the variable power regulator chip ) Many power supplies have a 7905 ( same as 7805 but reversed polarity ) for the - 5, or used a 7805 for the +5 VSB.

ALSO, note that the ON 110 volt switch on the back is a rather dumb, crude device, often with only 2 contacts ( the expensive ones have 4 contacts or " 2 " switches inside ). You could, as most newer manufacturers do, just ignore the switch, and short the switch out by jumpering across the terminals on the inside. This would mean that there was no way to turn off the VSB 5, but most computers do not have the switch in the first place, and have to be unplugged to really " turn " them off.
As well, you can just get a similar switch, and put it in, or get a totally different switch and mount it.

A few people have " thought" the switch was bad ( you can pop it apart and see if the contacts are burnt and corroded as a check ), but more often than not, in my experience, it is the power supply itself that is starting to fail. If you take out the 4 tiny phillips screws on the power supply case, and look inside, you can tell if there are burnt circuit board areas from overheated parts, or if the capacitors are split and leaking yellow fluid. Another failure is just plain DUST, and if the heatsinks and components are covered with dust, the unit will overheat....

Get a good pinout diagram and print it before wiring anything. A few models of computers used non-standard wire colours, and placements, so double check the power supply and the motherboard diagrams for your model..

Good luck !

Answer 2

If you use it for something like that. You'll have to rig up something to power it up since modern ATX power supplies unlike AT are powered on not on the power supply itself but on the motherboard. There may be a way to power it on...though I do not know of it. I'd assume that maybe 2 pins of the main motherboard power cable may be able to turn it on...but i seriously doubt it. Just sell the thing. If you want to power your trains and that off something use an AT power supply. Which has a switch contained in the wiring to turn it on.

Answer 3

You could use it for what ever you need ..... 3.3 volt, 5 volt, 12 volt. Direct Current.

If you wanted to use it to power your... something that uses batteries that would be easy.. I use some of those transformers that plug into walls sometimes instead of batteries.. My daughters have a Elephant game that has a fan that blows butterflies out its trunk. It took like 6 C batteries.. I hooked up an old Printer (transformer) power supply and now I don't need batteries. I would use that power supply as some kind of work bench power supply.

Answer 4

Nope, it is a SMART power supply, which balances the power for computer use. That means that it would probably detect a short when connected to a motor, and cut out all the time.

HEY, if the 350 W power supply is worth $5 to you, then try selling it at http://www.eptop.com or http://www.bidville.com or http://www.craigslist.com and get cash for it.

Answer 5

yes you can. small fans, lights, get a voltage tester to tell you how much power you have to play with. then work out what you can run of it,

Answer 6

You could proberly power some things off it, but it wouldn't be very advisable and best not to even really try.

Answer 7

You can power some neon sticks, case fans, watercooling systems.