Power Supply Unit

HoolyNI

Think my psu is on the way out, and am pondering whether to try and replace it or splash out and buy a new pc as mine is 9yo and still on xp.....though it does everything I require.

If I try and replace the psu I presume I'll need to find one thats pretty much a match for whats in place now....and am just wondering if theres a site where I can cross reference my model number?

Most of the psu's I've seen on ebay etc the fan appears to be on top of the unit while on mine the fan is beside the power switch, at the back so to speak.

Any advice would be appreciated.

Spank

If your machine is still running fine and is fast enough for you I wouldn't replace it.

Although they show PSU's with fan on top, it's actually on the bottom (modern cases have the PSU in the bottom of the case so it draws cool air into it rather than the warn air from inside the case). It won't make any difference in the way it works.

If it's a old Dell be careful as they wired the differently & plugging in a standard PSU can damage the computer.

Lum

Is your machine a generic box type with standard parts (i.e. not a major brand like Dell, HP, Compaq, Packard Bell etc.) if so then any ATX power supply of at least the same wattage should do.

Don't worry about te fan being on the top (actually on the bottom) rather than in the back. They're all designed to suck air in through the bottom and blow it out the back to cool your case down. Modern ones just moved it to the bottom as it allows for the use of larger, slower, quieter fans.

esuhl

Have a look at the PSU -- often it will say "ATX" on it somewhere (so you'll know it's a standard component). Other than the old Dells, or "small form factor" PCs, every PC I've seen has a standard ATX PSU.

In which case you just need to get a new PSU that's at least as powerful as your existing one. The power will be measured in Watts, so you might see a label that says "350W" or something... The power rating isn't always very accurate, so if you're getting a cheap PSU it might be worth getting one with a slightly higher power rating than you have now.

If the power supplied is too weak, the PC won't work. But there's no real advantage in having more power than you need -- it won't make your PC work any quicker, nor will it cause any problems (as the PSU only supplies the power that is needed -- the power rating is just the maximum).

closed

what are the symptoms

HoolyNI

Its been an ongoing saga......was randomnly losing signal from graphics to monitor then at other times pc would just switch off altogether, I then done a full system restore and reinstalled everything which seemed to cure previous problems but has left me now unable to shut pc down unless I switch it off at the back.

Just gets to the point "windows is now shutting down", you hear a loud click inside pc and something grinding to a halt, either fan or hard drive......i disconnected the power supply and sucked a load of dust out of it with the hoover but all that did was drop cpu temp from 74 to 65....still wont shut down.

Also doesnt seem to be any power getting to main switch at front of pc, it draws power from motherboard, had it covered up because bright blue light kept catching my 2 yo's eye but light is gone now....

closed

all drivers installed in device manager?

HoolyNI

Yes everything as it should be, except for shut down, and led light at the front.

Just checking my voltage 12v = 12.03, 5v = 4.38 and 3.3v = 3.26, so perhaps its not the power supply after all....

closed

does safe mode shutdown and turn off properly?

HoolyNI

Tried it in safe mode a few times, same problem, going to load ubuntu software and see what happens when i try to power off with it..... have also got the power switch/lights working again, but still fans etc keep running after pc goes through motions and sounding like it has switched off.

HoolyNI

Sorry, that voltage was a typo should have read 4.83.......Tried shut-down with ubuntu and same thing happens....fans keep running and led light on power button flashes as if pc was in sleep mode....presumably i can rule out a software issue now and concentrate on hardware??

Power switch is working ok now, power supply unit appears to be ok as does motherboard.....anyone any ideas what to look at next?