PC doesn't want to start

  • Thread starter Thread starter Bob H
  • Start date Start date
B

Bob H

Hi,
I have replaced the PSU with a known good and working one. I have
replaced the m/board with a brand new one., but the machine still won't
boot. What happens is that when I switch on from the back of the case,
because the front switch doesn't seem to do anything like that, the PSU
fan powers up, the cpu fan powers up, but then stops almost immediately.
I have pulled out the switch from the case to try it and it seems to
work ok, but even when the switch is disconnected from the board,
exactly the same thing happens again....starts up then stops.

What next?

Thanks
 
Bob H said:
Hi,
I have replaced the PSU with a known good and working one. I have
replaced the m/board with a brand new one., but the machine still won't
boot. What happens is that when I switch on from the back of the case,
because the front switch doesn't seem to do anything like that, the PSU
fan powers up, the cpu fan powers up, but then stops almost immediately.
I have pulled out the switch from the case to try it and it seems to work
ok, but even when the switch is disconnected from the board, exactly the
same thing happens again....starts up then stops.

What next?

Thanks
--


Bob H
Leeds UK
Click to expand...
Hi Bob,

Check to make sure that the CPU fan plug is in the right header on the
motherboard. If it isn't you can get exactly the symptoms you describe with
going on and straight off again. It's because the BIOS can't detect a
working fan on the CPU. The same happens if the CPU fan speed sensor is u/s.

HTH
SteveH
London
 
SteveH said:
Hi Bob,

Check to make sure that the CPU fan plug is in the right header on the
motherboard. If it isn't you can get exactly the symptoms you describe with
going on and straight off again. It's because the BIOS can't detect a
working fan on the CPU. The same happens if the CPU fan speed sensor is u/s.

HTH
SteveH
London
Click to expand...
Hi Steve,
thanks for the reply.
Well I can tell you that the CPU fan is plugged in at the right header;
it is next to the cpu itself, and it only fits one way.
Any other suggestions?
Thanks again

--


Bob H
Leeds UK

http://stores.ebay.co.uk/ContemporaryGifts4U
 
Bob H said:
Hi Steve,
thanks for the reply.
Well I can tell you that the CPU fan is plugged in at the right header; it
is next to the cpu itself, and it only fits one way.
Any other suggestions?
Thanks again

--


Bob H
Leeds UK
Click to expand...
OK, as I said b4, it could be that the speed sensor on the fan itself is
buggered or that the fan is running too slowly for the BIOS's liking. So -
can you try another fan?

SteveH
 
I got a comp here does that without fail. I just hit the reset button & it
starts. I figure the fan doesn't reach the required revs to satisfy & it
shuts down.
Never did it with a celeron in it but now I put a P3 in it it does it
without fail.
PCChips........... motherboard?
"shrugs..."
 
have you reconnected the switch?
when I turn this antec on from the back of the PSU, the case and cpu fans
spin very slightly then stop. I was always under the impression that ATX
PSUs did this on purpose, because I have seen it so often. I think your
switch is bad.
 
JAD said:
have you reconnected the switch?
when I turn this antec on from the back of the PSU, the case and cpu fans
spin very slightly then stop. I was always under the impression that ATX
PSUs did this on purpose, because I have seen it so often. I think your
switch is bad.
Click to expand...
In which case the o/p should try carefully shorting the two switch pins with
a screwdriver or or similar to see if it starts.

SteveH
 
have you reconnected the switch?
In which case the o/p should try carefully shorting the two switch pins
with a screwdriver or or similar to see if it starts.

SteveH
Click to expand...

I am glad to see someone posted the same problem I am having.
I have an Antec 350 ps running an MSI K7420 pro board with a 1800 AMD
processor and 1.5 ram with Win XP.
This machine worked perfect until I had swapped the CPU/Fan/memory with
another computer with the same board for diagnostic purposes.
That machine booted fine. I have reinstalled all the parts into the
original system and got the same problem as described here. :(
My question is how do you short the switch pins? I do have a volt meter but
I do not know how to use it. It was my late husbands.



Thanks

Cindy
 
Cindy said:
I am glad to see someone posted the same problem I am having.
I have an Antec 350 ps running an MSI K7420 pro board with a 1800 AMD
processor and 1.5 ram with Win XP.
This machine worked perfect until I had swapped the CPU/Fan/memory with
another computer with the same board for diagnostic purposes.
That machine booted fine. I have reinstalled all the parts into the
original system and got the same problem as described here. :(
My question is how do you short the switch pins? I do have a volt meter
but I do not know how to use it. It was my late husbands.
Click to expand...
If you examine the mother board where the connectors (little pins and plugs)
from the front case
connectors are fitted, you will see a pair of pins that say PWR. If you
connect or bridge these with the metal end of a small srewdriver, your power
supply should start up.You will of course have the back switch in the On
position. Hope this helps..OJ
 
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