Problem with computer , might be wrong group to post in

  • Thread starter Thread starter LouisG
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L

LouisG

Sorry if this is off topic for this group , but , the computer i'm having
problems with does run Xp if that counts for anything. LOL

When you turn the computer on you can hear the hard drive very quietly
turning over , but there is no beeps , or anything coming up on the
screen.

I've tried a new video card , tried taking the ram out and putting them
back in one at a time , tried many different hard drives and cables ,
getting good output from the power supply/fan.

I'm beginning to think that the motherboard is pooched but was wondering
if anyone else thought differently.

Thank you for any forthcoming input.

Gord
 
No beeps , no sign of life at all other than hearing a little whir from
the h/d and the cd drives
 
LouisG said:
I don't even get to the post messages , or the bios screens , nothing

If it was mine, I'd disconnect hard drives and optical drives,
remove the video card (and store in an antistatic bag), remove
the RAM (all of it, store in an antistatic bag). That leaves
a motherboard, a processor with cooling, and the computer speaker
(either a piezo on the motherboard, or a computer case speaker).

When started in that condition, you'd expect to hear the missing
RAM beep pattern. For the motherboards I know about, the beep is
made under BIOS program control, and it is a good health indicator
that the CPU is still working.

If there are no beeps, then either the motherboard, processor, or power
supply is holding it back. You can check the voltages on the power supply.
(The metal contacts in the main connector, are accessible with a multimeter
probe, from the backside of the connector.) If the voltages are
all present (+3.3V, 5V, 12V, -12V, +5VSB), then it probably isn't
the power supply. That would leave processor and motherboard,
and generally processors are pretty reliable. The current generation
have overheat protection, and the power supply would be shut off,
if the processor was overheating.

So, if you get to that point, then I'd have to assume it was the
motherboard. Processors do fail, but with a pretty low frequency.
Power supplies, on the other hand, die like flies :-)

Check that the ATX12V 2x2 connector and the main power connector
are fully seated. A missing 2x2 connector, will give the symptoms
you are seeing.

If you have any further symptoms to add, please include make
and model number info, for the computer, or make and model
number info for the motherboard. Sometimes, it helps to know the
vintage of the equipment. For example, old slot 1 systems with
the SC242 connector, the connector itself can be a bit flaky.
(Remove and reinsert processor in that case, and try again.)
Later generations of CPU sockets are better quality, and
don't seem to be subject to quite the same level of contact
issues.

Paul
 
Paul said:
If it was mine, I'd disconnect hard drives and optical drives,
remove the video card (and store in an antistatic bag), remove
the RAM (all of it, store in an antistatic bag). That leaves
a motherboard, a processor with cooling, and the computer speaker
(either a piezo on the motherboard, or a computer case speaker).

When started in that condition, you'd expect to hear the missing
RAM beep pattern. For the motherboards I know about, the beep is
made under BIOS program control, and it is a good health indicator
that the CPU is still working.

Thanks for the info Paul , i disconnected everything you mentioned with no
beeps happening on start up.
I didn't have my meter with me , so i couldn't try the power supply , but
i'm assuming that the connector you're talking about is the main connector
to the motherboard?
 
LouisG said:
Thanks for the info Paul , i disconnected everything you mentioned with no
beeps happening on start up.
I didn't have my meter with me , so i couldn't try the power supply , but
i'm assuming that the connector you're talking about is the main connector
to the motherboard?

Yes. I'd measure the voltages on the main connector. I connect the ground of
my meter, to a screw on the I/O area on the back of the computer. That way,
I only have to handle the red meter lead, while probing the main connector.

For pinouts, you can get ATX specs from formfactors.org .

http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf (page 30)

http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf (page 37)

You can also check the ATX12V 2x2 connector, the one with two yellow wires
and two black wires. The yellow wires should have +12V on them. Dual rail
supplies will use a separate output to drive the yellow wire on the main
connector, versus the two wires on the ATX12V connector. But that does not
necessarily mean the two different sources are completely independent of
one another (they may be current limited outputs coming from the same
source). If it is a dual rail supply though, you can check both
12V1 and 12V2 rails. (12V2 is on the ATX12V 2x2 connector, while
12V1 powers hard drives and the motherboard main connector, yellow wire.)

It is best to leave the power supply connected to the system, as the
system will present a load for the power supply. While it probably
doesn't hurt the average supply, to be operated without a load on it,
there may not be a guarantee that is always the case. I have a load box
to use, if I want to test the power supply alone.

Paul
 
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