Dead Computer

  • Thread starter Thread starter BrianXZ
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BrianXZ

Hello there. I've got quite an old computer that recently died. One day is
didn't switch on. I fiddled with the power cable and it started working
alright. But the next day when I switch it on it was dead again..
There was no activity at all, no fans, beeps etc. So naturally I suspected
the Power Supply Unit. (It is a standard ATX) So I bought a new power
supply, connected it to the motherboard and switched it on
and.......................

Nothing. Well the fan on the power supply comes on briefly but nothing. The
computer is still dead. I then thought the front power switch on the
computer may be faulty, so I located the switch connector on the motherboard
and shorted that with a screwdriver. But again nothing.
Can anyone suggest what might be the problem. It's not the power supply or
motherboard switch.

To recap. When I switch it on, The fan very briefly (1/2 second) tries to
come on but nothing else happens. No fans, beeps or any sound at all.

Thanks.
 
I had the same problem with a Gigabyte GA7-400L-L1 motherboard. The
grounding on the M/O is out or doens't think a power supply is there. I had
to RMA my M/O.
 
c0lored_ardvark said:
I had the same problem with a Gigabyte GA7-400L-L1 motherboard. The
grounding on the M/O is out or doens't think a power supply is there. I had
to RMA my M/O.
Click to expand...


I took the motherboard out and placed it on a desk with just the processor
and memory attached. I connected the power supply and the fan on the power
supply and the cpu very briefly come on then stopped.
Again I tried short circuiting the switch on the motherboard but nothing
happened. Is the motherboard faulty in some way?
Thanks.
 
try it without the memory and the cpu. If it still
won't turn on then at least the mobo is fried.
 
Since you tried changing the power supply unit, that probably means that the
motherboard itself has died.
 
To recap. When I switch it on, The fan very briefly (1/2 second) tries to
come on but nothing else happens. No fans, beeps or any sound at all.
Click to expand...

To recap, you may need to re-cap... : )

Check the capacitors (tall cans) on the mainboard for any swelling or brown
stuff underneath.
 
Presumable the computer has some method of switching itself
off to protect it self, well either the power supply or the
computer.

I assume it is switching itself off, rather than a short circuit
drwaing all the power (in which case you would probably
notice a burning smell).

It would be handy if you had a multimeter so you could prob
around for voltages.

I am just guessing really as how the power supply fan switches itself
off, I assume there is a circuit breaker somewhere?

http://www.fonerbooks.com/power.htm

Anyway I am no expect so maybe the above link mayhelp.


"Check the switch operation with a Digital Volt Meter on the continuity or
resistance setting. On all ATX systems, the power switch is really just a
logic switch that tells the motherboard, to which a trickle of live power is
always supplied, to instruct the power supply to come fully alive."

I think this answers my question!
So the mother board has failed to tell the powersupply to come on fully,
the question is of course why?
Anyway the above link know far more than I will ever know.

A good visual inspection of components on the MB is a good idea,
leaking capacitors etc...and melted components etc.. also
check the connectors are clean and properly connected.

Striping the system down to the bare minimum might be a good idea
(minimum ram, no drives etc...) as might cleaning out dirt an dust etc.

Taking what you can apart and putting togeather again may help.

Ideally you would want an identical MB and chips to swop things about.

Maybe buy one on Ebay?

Any the above link has a lot of info on it.
 
Hello there. I've got quite an old computer that recently died. One day is
didn't switch on. I fiddled with the power cable and it started working
alright. But the next day when I switch it on it was dead again..
There was no activity at all, no fans, beeps etc. So naturally I suspected
the Power Supply Unit. (It is a standard ATX) So I bought a new power
supply, connected it to the motherboard and switched it on
and.......................

Nothing.
Click to expand...

What, exactly, does "fiddled with the power cable" mean?
Had you considered that if the power cable had been making poor
contact with the old PSU socket, that it may've been arching,
that the old cord may be the problem so you might need a cord,
not a psu?
Well the fan on the power supply comes on briefly but nothing. The
computer is still dead. I then thought the front power switch on the
computer may be faulty, so I located the switch connector on the motherboard
and shorted that with a screwdriver. But again nothing.
Can anyone suggest what might be the problem. It's not the power supply or
motherboard switch.

To recap. When I switch it on, The fan very briefly (1/2 second) tries to
come on but nothing else happens. No fans, beeps or any sound at all.
Click to expand...

Strip system down to minimal compunents: cpu, cpu heatsink fan,
video, 1 memory module (or two for rimms), but nothing else
connected to either motherboard or power supply. Again try
shorting power-switch pins. If nothing, check board jumpers (if
any) and clear CMOS with AC disconnected from the psu.

This new power supply, is it known decent quality, and did you
check the AC input voltage selector switch on the rear?
 
kony said:
What, exactly, does "fiddled with the power cable" mean?
Had you considered that if the power cable had been making poor
contact with the old PSU socket, that it may've been arching,
that the old cord may be the problem so you might need a cord,
not a psu?


Strip system down to minimal compunents: cpu, cpu heatsink fan,
video, 1 memory module (or two for rimms), but nothing else
connected to either motherboard or power supply. Again try
shorting power-switch pins. If nothing, check board jumpers (if
any) and clear CMOS with AC disconnected from the psu.

This new power supply, is it known decent quality, and did you
check the AC input voltage selector switch on the rear?
Click to expand...
"What, exactly, does "fiddled with the power cable" mean?"
Click to expand...

When it wouldn't come on the first time I instinctively thought the power
cable might not be all the way in so I twiddled it around and pushed it all
the way in the socket.
There is nothing burnt on the motherboard. Unfortunately I don't have a volt
meter at hand. Anyway thanks for the advice everyone. I'll try everything
over the next few days, and I may buy a new motherboard, the old ones seems
to sell for around £10 -£20
 
Hello there. I've got quite an old computer that recently died. One day is
didn't switch on. I fiddled with the power cable and it started working
alright. But the next day when I switch it on it was dead again..
There was no activity at all, no fans, beeps etc. So naturally I suspected
the Power Supply Unit.
Click to expand...

Why? Why would you not suspect the power cord?...or even the
connection at the wall or at the ps?

Check the 3 leads on the cord with an ohm meter. Or buy a different
cord...they're cheap.


Hope ya'll have a nice 4th of July weekend...

Trent©


Proud member of the Roy Rogers fan club!
 
BrianXZ said:
Hello there. I've got quite an old computer that recently died. One day is
didn't switch on. I fiddled with the power cable and it started working
alright. But the next day when I switch it on it was dead again..
There was no activity at all, no fans, beeps etc. So naturally I suspected
the Power Supply Unit. (It is a standard ATX) So I bought a new power
supply, connected it to the motherboard and switched it on
and.......................

Nothing. Well the fan on the power supply comes on briefly but nothing. The
computer is still dead. I then thought the front power switch on the
computer may be faulty, so I located the switch connector on the motherboard
and shorted that with a screwdriver. But again nothing.
Can anyone suggest what might be the problem. It's not the power supply or
motherboard switch.

To recap. When I switch it on, The fan very briefly (1/2 second) tries to
come on but nothing else happens. No fans, beeps or any sound at all.

Thanks.
Click to expand...
Before you blow big bucks, try Trents suggestion. I have had bad power
cords. And even a bad cord can give a momentary surge to spin the fan a few
seconds. BobV
 
BobV said:
Before you blow big bucks, try Trents suggestion. I have had bad power
cords. And even a bad cord can give a momentary surge to spin the fan a few
seconds. BobV
Click to expand...

I've tried it with 2 power cables and no joy with either.
I think the motherboard must be faulty
 
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