power supply problem

[Guest]

I few weeks ago my brother’s computer wouldn't start on the first power up.
When you push the power button, it would turn off 2 seconds later. After 10
to 20 tries I would get it to boot up and it would work find until he turned
off the computer again. I tested everything from the motherboard, CPU, power
supply to the motherboard and everything seem to work find. After testing
everything and putting everything back, the computer worked without any
problems for almost two weeks before started to act up again. I tried
switching the voltage switch on the power supply to 230V and it works every
time but when I put it back to 115V, the problem returns. I live in Canada
and everything is 115/240V. Does anyone why it works on 230 and not on 115?
Will it fry computer parts at 230V?

Thanks,
Kristopher

P.S. Every other computer (3 others) work find on 115v.

 

[Carey Frisch [MVP]]

I would suggest replacing the power supply unit.

--
Carey Frisch
Microsoft MVP
Windows XP - Shell/User
Microsoft Newsgroups

Get Windows XP Service Pack 2 with Advanced Security Technologies:
http://www.microsoft.com/athome/security/protect/windowsxp/choose.mspx

-------------------------------------------------------------------------------------------

:

| I few weeks ago my brother’s computer wouldn't start on the first power up.
| When you push the power button, it would turn off 2 seconds later. After 10
| to 20 tries I would get it to boot up and it would work find until he turned
| off the computer again. I tested everything from the motherboard, CPU, power
| supply to the motherboard and everything seem to work find. After testing
| everything and putting everything back, the computer worked without any
| problems for almost two weeks before started to act up again. I tried
| switching the voltage switch on the power supply to 230V and it works every
| time but when I put it back to 115V, the problem returns. I live in Canada
| and everything is 115/240V. Does anyone why it works on 230 and not on 115?
| Will it fry computer parts at 230V?
|
| Thanks,
| Kristopher
|
| P.S. Every other computer (3 others) work find on 115v.

 

[Guest]

I did with another power supply from one of my computers. Same power supply
and everything.

 

[GTS]

Switching the PSU to 230V was a huge risk if it's really on a 115V circuit.
It could well have fried the system. Perhaps this unit has some
detection/protection built it. It's an odd situation but here's a few
thoughts. Sometimes a failing device may draw excessive power.
Disconnecting / removing devices like the CD drive, floppy drive if present,
boards other than video, etc. is a way to test that. Also, have you checked
the outlet voltage? If there is a surge protector that could be suspect as
well.

 

[GTS]

On thinking a little more about your post, I may have overstated the risk
since we're referring to the input voltage to the PSU and 115->230 not
230->115, though the suggestions remain sound.
--

 

[Mistoffolees]

I did with another power supply from one of my computers. Same power supply
and everything.

Get an electrician to check the particular circuit to
which the computer is connected. Although 115V is used
for almost all home use, there are still 230V lines for
the kitchen stove, clothes dryer, etc. What is really
unclear is why the PSU did not get fried, literally,
when hit with the 230V whilst at the 115V setting. The
internal protection, fuses and breakers, would not have
acted fast enough.

 

[Guest]

I am a second year electrical apprentice with over 6 year of computer
experience and I couldn't find anything that could be wrong with the computer
nor the circuit. Maybe it’s my multi-meter that’s not working right. I'll
try booting the computer out with just the one hard drive and no cd rom and
see if that works. I'll also calculate to make sure my power supply strong
enough. It's a 400w which should be for two hard drive, dvd-rom, cd burner,
video card, sound card and nic card.

thanks for your replies
Kristopher

 

[GTS]

You're welcome. I'm curious to see what you find. It is a most unusual
problem. Good luck.