Jump Start a PSU

by F1X0R

41K2119

Intro: Jump Start a PSU

This Guide Will teach you How to start a computer PSU (power supply unit) with out need for a motherboard. you'll be able to power any component with no need to fiddle with switches and jumpers. and if you want to "leak test" a water cooling kit with out getting an expensive MOBO wet then this is really good. It couldn't be more simple.

you will need;

a PSU, - if you figured this one out, you have the brain cells to complete this instructable

Wire Strippers / side cutters or cigarette lighter, anything you can use to remove some of the plastic off the

some cheep electrial wire (can be ripped from Ethernet cable) i got mine fo £0.80 (just under $2) from rapid electronics

electrical tape

optionally you may want a soldering iron and some solder.

STEP 1: The First Bit

Ok this bit is very simple.

basically strip the plastic coating of both ends of the wire to expose the bare metal core.

see photos.

STEP 2: The Main Stuff

first of all you CAN PLUG IN AND TURN ON THE PSU you won't get electrocuted because the unit is grounded. you aren't the quickest way to earth in doing this.

turn the PSU off on the back of it, purely because some PSUs wont turn on if you do the next bit first then this! and you'll have to do it in the right oder.

look at the first image, you'll find there will be a green wire (similar to the one under my thumb) there should only be one, how ever i have seen two before (as on this one) you want the lighter green one.

You'll see that this connects into the plastic part of the "plug." in the plastic plug at the top there is a bit of metal it will be hollow, stick one of the bare ends of wire into that.

next stick the other end into any of the black wires, there are a few so take your pick.

find the rocker switch at the back of the PSU (not all PSUs have this so you may need to turn it off from the mains in the first place) turn it on. the fan will start the PSU will supply Power to all the components connected.

STEP 3: Read This Bit.


IT is important that if you want to connect any components after you've tested your jump started PSU that you switch it off via the mains first then add what ever component you want to then turn it on. if you turn the PSU on then connect the molex adapter to the advice, you will create a nice blue spark and cry when you realise that the component is now dead.

same goes when you are building a PC.

also if you want a 12v supply with upto 5 amps you can cut the red and black wires free (sounds like bomb disposal) of the molex and strip the ends. this will give you a nice supply for what ever.

19 Comments

danielemur 13 years ago

What if you have a psu with out a switch?

F1X0R 13 years ago

Um, I haven't seen that before really. Still I suppose you'd have to just use the wall socket in stead of the switch on the PSU.

tin701 15 years ago

lol even though I already knew how to do this I still enjoyed it! great instructable. i laughed so hard when i read this: "you will create a nice blue spark and cry when you realise that the component is now dead."

F1X0R 15 years ago

Happened to me once, lucky it was only an old hard drive with nothing important saved on it. Had it of been anything else, I may have cried.

lilpepsikraker 14 years ago

Happened to me too once, it was a 40GB Maxtor Fireball (7200RPM). And I did cry, lol.

12V 14 years ago

12v is the yellow wire(or orange)!

F1X0R 14 years ago

Sorry. I thought I corrected that little gaff ages ago.

ekulmeekul 15 years ago

nah its to test if ur liquid cooling leaks anywhere not to test plants!

n0ukf 16 years ago

The red wires are the 5v not 12v supply. 12v is on the yellow wires. Older AT supplies don't need this jumper, they just may need a load resistor as drcrash mentioned. and they always have a power switch of some kind.

F1X0R 16 years ago

this instructable doesn't deal with converting the power supply to a bench tester. merely running it with out having to use a motherboard. so i fail to see your point. they may have some similarities. though it wasn't I that said anything about mimicking a load. this instructable just deals with how to make it start to use the molex adapters to test things like water cooling units hard drives etc with out need for a motherboard. this leads me to think you havn't actually read what is in the instructable.

gamer 16 years ago

he showed us how to turn on a psu without a motherboard, i needed this the other day, and it wasnt for a bench tester. this instructable is very instructive. -gamer

drcrash 16 years ago

There are already several Instructables on how to convert an ATX computer power supply to a standalone power supply for whatever. (Including the part about using a resistor to make sure you present the minimum load so that the think works.)

https://www.instructables.com/id/ATX--%3e-Lab-Bench-Power-Supply-Conversion/

https://www.instructables.com/id/Yet-Another-ATX--Lab-Bench-Power-Supply-Conversion/

https://www.instructables.com/id/Convert-an-ATX-Power-Supply-Into-a-Regular-DC-Powe/

Hands Without Shadows 16 years ago

Many modern psu's need a load to turn on. A 10 watt, 10 ohm resistor from Radioshack between a red and black wire will work.

bleachworthy 16 years ago

You'd be suprised how many you can jump start like this. I've only found one that needed a load, and it was an ancient AT style. I flipped the switch, and the fucker went up in smoke! I usually just use a bent paperclip to start up my test PSU.

F1X0R 16 years ago

oops, lol guess thats what you get for doing this at 01:00 in the morning.

mikesty 16 years ago

A paperclip works really well. I've always got one in my wallet, so I just whip it out, short green-to-black (any black), plug it in, and go. :) Good instructable.