Mobo or CPU dead?

  • sean5302
  • Student
  • Student
  • sean5302
  • Posts: 65

Post 3+ Months Ago

A friend's young daughter has a 4 year old Packard Bell pc with Celeron socket 478 CPU and micro ATX mobo.

Recently they got cable internet, via Virgin, so the young girl started using the pc a lot more.

She says all was OK yesterday, but today it wouldn't turn on.

I opened it up and checked:

PSU is OK when I bridge the green and black wires. All voltages seem fine
Checked power switch. Intermittent type and works OK.
Disconnected HDD, DVD drive, CDROM drive etc and hoped to get the mobo to do POST but nothing.
Removed RAM and re-installed it.
Removed CPU and re-installed .

I'm stuck now.

I haven't got another socket 478 CPU to swap.

What do people think is the likeliest problem? The family hasn't got much money so I don't want to buy something they don't need.

Also, if I change the mobo, almost certainly Windows XP Home won't like it and may not start.

Any help you can offer, please?
  • Anonymous
  • Bot
  • No Avatar
  • Posts: ?
  • Loc: Ozzuland
  • Status: Online

Post 3+ Months Ago

  • Don2007
  • Web Master
  • Web Master
  • Don2007
  • Posts: 4924
  • Loc: NY

Post 3+ Months Ago

I know you said you tested it but are you sure that the power supply is good? That's what goes first.
  • sean5302
  • Student
  • Student
  • sean5302
  • Posts: 65

Post 3+ Months Ago

Thank you.

Your response has got me testing a bit more.

I originally tested the power supply separately. Today I plugged everything back into the PC and again bridged the green and black wires on the large 20-pin connector.

The PC then works fine.

I tested the power switch on the front case of the PC, which is OK so my problem is the power switch is not activating the power supply. Is that a PSU fault?
  • sean5302
  • Student
  • Student
  • sean5302
  • Posts: 65

Post 3+ Months Ago

Don2007, you've helped me.

I did a bit more investigation and found that there should be a 5V primary voltage on the purple wire on the 20-pin plug from the power supply unit.

It's actually varying between 0.3V and 0.95V so you were right. The PSU is u/s. It smells a bit burnt, actually.

So, I found a suitable replacement on eBay, brand new for £10 (about $20 ).

I'm very grateful to you. Thanks very much.
  • Don2007
  • Web Master
  • Web Master
  • Don2007
  • Posts: 4924
  • Loc: NY

Post 3+ Months Ago

You're welcome.

Post Information

  • Total Posts in this topic: 5 posts
  • Users browsing this forum: No registered users and 44 guests
  • You cannot post new topics in this forum
  • You cannot reply to topics in this forum
  • You cannot edit your posts in this forum
  • You cannot delete your posts in this forum
  • You cannot post attachments in this forum
 
cron
 

© 1998-2014. Ozzu® is a registered trademark of Unmelted, LLC.