Failed PSU?

  Kernel 22:21 21 Feb 08
Locked

My computer recently failed completely, it would not even POST, no bleeps - nothing.
I replaced the mobo, processor, AGP card and memory and the same condition still appeared.
The computer runs up, there is power to fans, the memory light comes on, I can see it polling through the CD player etc but the hard disk LED comes on for about 5 seconds and then goes off with nothing at all on the monitor.
I have now come to the conclusion that somehow the power to the mobo itself has failed and that, whilst the 'peripherals' are powered up the actual mobo and dependent processing functions are not receiving power. The PSU was 350 watts and I think I need a bigger one. Does anyone agree?

  Technotiger 22:25 21 Feb 08

Certainly sounds as if you need a more powerful PSU, I would suggest 450w - 500w and the best Quality that you can afford. A good quality 450w is better than a poor quality 600w.

  skidzy 22:26 21 Feb 08

Definately replace the psu asap,this can blow the new mobo if the psu is faulty.
Ebuyer has a several psu's,branded would be best at 500watt upwards.click here

  mrwoowoo 01:15 22 Feb 08

How can you know it needs a more powerful psu without knowing the system specs?
Not saying you are wrong,just curious.
Could it not be a failed hard drive for instance?

  Kernel 09:07 22 Feb 08

I worked on the assumption that if I had tried two similar systems in the same tower and both had dislayed the identical symptoms then there was a reasonable probability that the systems were OK and that the common point of failure was within the tower, there is only one working item in the tower - the PSU. Given that the PSU had to be replaced it seems prudnt to fit a larger one, I was aware that 350watts was on the lower limit for a modern set up. I had tried two other redundant but working hard drives with both systems but with the same result.

Many thanks for the constructive comments, at least no one disagreed with me!!

  Technotiger 09:16 22 Feb 08

Hi, for exactly the reason that Kernel has stated - 350w is very much on the lower limit. When a PSU is suspect, I believe the most common reason is 'not enough power' so things start to go wrong.

  skidzy 15:39 22 Feb 08

Your statement aimed at Technotiger;
" How can you know it needs a more powerful psu without knowing the system specs?

Yes you have a fair comment,however as im sure you are aware of .....Dell / PCW etc ship with just a basic psu,something in the region of 250-350watt sometimes slightly bigger.

As we know these are underpowered psu's and almost certainly would need upgrading if an extra harddrive,dvd drive,or even a graphics card of worth was added.

As said,todays psu's are just not man enough to take any upgrades.This i can speak from experience though am a little shocked you could point that statement at Technotiger when you obviously know you way around a computer.

kernal
Obviously take onboard the statement that the hdd may be dying or faulty/corrupt.

  woodchip 15:43 22 Feb 08

Also to add to the above, a good 250 watt can sometimes be better than a cheap 500watt and last longer

  skidzy 15:49 22 Feb 08

fair play there Woody...but unlikely with generic psu's shipped with retail computers.

Though i should add,the retail computers i have bought from Dell and PCW have served me fine with there standard psu's...but only till i upgrade them,and from experience,i now install a new psu as i was sick of blown mobo's.

Though each and everyone to there own i suppose.

I would always advise to buy a branded psu,however as you know Woody i rebuild socket 478's and 775's and the Antec and Casecom psu's from Ebuyer serve me just fine...no failures to date..(yet !) though these are not high powered systems,just basic needs.

  gazzaho 16:13 22 Feb 08

From what I've tread elsewhere on the web, modern day graphics cards need 200+ watts in order to run properly, I don't know for sure if this is correct but you need a beefy power supply to run an SLI set-up 650watt or higher as far as I'm aware, so I guess this points towards it being true. I would say that a 350watt power supply would seem to be on the low side for a modern system. I don't know how much power hard drives and other peripherals consume but I personally would get a more powerful supply, definitely 500watt minimum, but that’s my personal opinion.

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