psu fan spins as soon as power cord attached...

  • Thread starter Thread starter dw
  • Start date Start date
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dw

.... without pressing 'ON' switch.

PC wouldn't start this morning, so I assumed that my psu had blown and tried
another. The fan spins as soon as the power cord is attached. Tried 2 other
known working psu's with same result.
On each occasion had the 20-pin ATX cord attached and the 4-pin Pentium-4
cord attached to motherboard - tried with/without HDD attached.

Is it likely to be motherboard problem?

TIA,
relkeel
 
dw said:
... without pressing 'ON' switch.

PC wouldn't start this morning, so I assumed that my psu had blown and tried
another. The fan spins as soon as the power cord is attached. Tried 2 other
known working psu's with same result.
On each occasion had the 20-pin ATX cord attached and the 4-pin Pentium-4
cord attached to motherboard - tried with/without HDD attached.

Is it likely to be motherboard problem?
Click to expand...
BIOS setting of power fail/resume option?

The computer that I am typing this on is set to restart after power fail
and so starts as soon as the power cord is plugged in. This is
intentional and not a fault.
 
Palindr?me said:
BIOS setting of power fail/resume option?

The computer that I am typing this on is set to restart after power fail
and so starts as soon as the power cord is plugged in. This is intentional
and not a fault.
Click to expand...
Thanks for quick reply.
I am unable to get into BIOS as the PC will not boot - sorry if I didn't
make that clear. The PSU fan spins but PC will not start - with one of the
PSU's I tried the hard drive light just constantly pulsed on/off but nothing
else happens.
 
dw said:
Thanks for quick reply.
I am unable to get into BIOS as the PC will not boot - sorry if I didn't
make that clear. The PSU fan spins but PC will not start - with one of the
PSU's I tried the hard drive light just constantly pulsed on/off but nothing
else happens.
Click to expand...
So the psu fan spins and, presumably, the processor fan spins and the
power on LED lights? But no beeps?

Any of the capacitors (tall cylindrical things) leaking or having a top
that is convex upwards? Very common, unfortunately.

It could be a faulty mobo and/or processor and/or memory. But the
starting point is to take the memory completely out and reseat it.
Amazing how often it is just a bad connection there. No harm in trying
that with the processor, afterwards, and working you way around all the
plug in chips on the mobo and making sure they are pushed well home.
Pins do have a habit of "walking out" with the thermal expansion changes
of cold (off) and warm (on).


If that doesn't return things to normal, I'm afraid it's substition time
by shoving the memory then the processor in a working system. If they
both work ok, then it is probably the mobo that has joined the choir
eternal.
 
Palindr?me said:
So the psu fan spins and, presumably, the processor fan spins and the
power on LED lights? But no beeps?

Any of the capacitors (tall cylindrical things) leaking or having a top
that is convex upwards? Very common, unfortunately.

It could be a faulty mobo and/or processor and/or memory. But the starting
point is to take the memory completely out and reseat it. Amazing how
often it is just a bad connection there. No harm in trying that with the
processor, afterwards, and working you way around all the plug in chips on
the mobo and making sure they are pushed well home. Pins do have a habit
of "walking out" with the thermal expansion changes of cold (off) and warm
(on).


If that doesn't return things to normal, I'm afraid it's substition time
by shoving the memory then the processor in a working system. If they both
work ok, then it is probably the mobo that has joined the choir eternal.
Click to expand...
OK, I'll give all those suggestions a try - thanks.
 
Palindr?me said:
So the psu fan spins and, presumably, the processor fan spins and the
power on LED lights? But no beeps?

Any of the capacitors (tall cylindrical things) leaking or having a top
that is convex upwards? Very common, unfortunately.

It could be a faulty mobo and/or processor and/or memory. But the starting
point is to take the memory completely out and reseat it. Amazing how
often it is just a bad connection there. No harm in trying that with the
processor, afterwards, and working you way around all the plug in chips on
the mobo and making sure they are pushed well home. Pins do have a habit
of "walking out" with the thermal expansion changes of cold (off) and warm
(on).


If that doesn't return things to normal, I'm afraid it's substition time
by shoving the memory then the processor in a working system. If they both
work ok, then it is probably the mobo that has joined the choir eternal.
Click to expand...
For anyone remotely interested it was the mobo.
 
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