PSU not working.

Fordun

Beta member
Messages
3
I tried to upgrade my PSU from an old 250watt to a Corsair CX500 and its not working.
I cant turn on my computer i connect everything that my old PSU was connected to and i dont get jack.

The only good news is there is a green light on my mother board so i guess im getting power but why cant i turn on my computer?
 

tj107us

Baseband Member
Messages
76
Have you tried jumping the green wire to a black wire on the 20 to 24 connecter? When you try that and it still don't run then you my friend have a bad psu, then you need to return it and get another one.
 

Atomic Rooster

Omnipotent One
Messages
11,161
Location
USA
Is the Corsair PSU a new unit or a used power supply? Check to see if the power switch wire from the front of the case properly connected to the motherboard.
 

Fordun

Beta member
Messages
3
Have you tried jumping the green wire to a black wire on the 20 to 24 connecter? When you try that and it still don't run then you my friend have a bad psu, then you need to return it and get another one.
What do you mean by "umping the green wire to a black wire on the 20 to 24 connecter"

Is the Corsair PSU a new unit or a used power supply? Check to see if the power switch wire from the front of the case properly connected to the motherboard.

Its a new PSU i just got yesterday.
And how do i "Check to see if the power switch wire from the front of the case properly connected to the motherboard."
 

Atomic Rooster

Omnipotent One
Messages
11,161
Location
USA
There should be a few wires from the front of the case that are attached to a small strip of pins on the motherboard. The wires and the pins should be labeled as to their proper positionand polarity. You motherboard manual will also show the proper location.

Here's something that will help: Computer Wiring: How to Connect Your Computer Wires



tj1986 suggestion of "jumping" the PSU isn't always a good indicator of PSU health. Even a malfunctioning power supply may start up using this method.

Turn on PSU without motherboard - the 'paperclip trick'
 

Fordun

Beta member
Messages
3
Update - i took out the corsair and put in the old psu to see if it would still work...It doesnt but this does mean that my Cosair is fine but someone else is messed up.
 

tj107us

Baseband Member
Messages
76
I didnt read the post too well i guess, cause you said you think it is getting power to the mobo, because you are getting a led on the motherborad to work, so yeah do what Atomic Rooster said and check to make sure you hooked up the wires from the power switch, power LED, HDD LED and the speaker.

Atomic Rooster: the power switch leds dont have a polarity do they? Its just the LED's Correct me if im wrong.
 

westom

Baseband Member
Messages
25
Update - i took out the corsair and put in the old psu to see if it would still work...It doesnt but this does mean that my Cosair is fine but someone else is messed up.
It only means insufficient facts existed to know anything useful.

For starters, you should have known this. A defective supply may still boot a computer. A perfectly good supply can be defective in an otherwise perfectly good system. And defective computer hardware can make some otherwise perfectly good power supplies appear to be defective. In short, informed techs do not swap parts to learn what is defective.

Your replies will only be as useful as facts that you first provide. That means, for example, numbers. To have a reply without wild speculation means you must first 'see' something that can be posted. Voltages. Never see voltages without a multimeter (sold only in stores where geniuses are allowed to shop (ie Kmart, Wal-Mart, Radio Shack, Lowes). And extremely expensive ($17 in Wal-Mart; $4 in Harbor Freight). Without a multimeter, then facts necessary for a useful answer are no posted.

One minute of labor. Measure (on the 20 VDC scale) voltages on a green, gray, and purple wire both before and when the power switch is pressed. Report those numbers here to have an answer based in facts. Then boot the machine. Have it drawing maximum power from all peripherals. That means no Prime95. That means multitasking. Searching each drive, while reading a CD-Rom, while downloading from the Internet, while powering from a USB device, while playing sound loudly, while moving the mouse, while ... now measure the voltages on any one red, orange, or yellow wires. And report those numbers to three significant digits. Or if the system does not power, then report the behavior of each voltage as the power switch is pressed.

Do same for a 250 Corsair and for the new supply.

Once numbers are provided, then the few who actually know how computers work will report what is wrong. Without speculation. And also explain how a computer works on power up. No numbers means no useful reply is possible (which is true for more than just computers).
 
Top