Can't get any display...

[mattclarkes]

For the second time in a week, i've run into this problem..
computer comes in to be fixed, because they can't get anything o
their monitors
i hook it up to any of my monitors and the same thing, no signal
monitor does come on (stays in stand-by, amber light
test and change powersupply, no differenc
test and change ram, no differenc
test and change video cards, no differenc
test and change CMOS battery, no differenc

no matter what i do, i can't get vide

the fans all come on and turn, and power is being sent to th
harddrive, keyboard, cd rom, et

also, i get no beeps...the speaker is plugged into the motherboard
but even with no ram installed, no beeps

normally, i'd diagnose it as a bad motherboard, but this is the secon
one for sure with the same problem, and another one is on it's way i
with similar problems...and they are all different boards (one is a
asus, the other is in a compaq

any help, or ideas would be greatly appreciate
any information on something that may be targeting the vide

 

[Paul]

For the second time in a week, i've run into this problem...
computer comes in to be fixed, because they can't get anything on
their monitors.

i hook it up to any of my monitors and the same thing, no signal,
monitor does come on (stays in stand-by, amber light)
test and change powersupply, no difference
test and change ram, no difference
test and change video cards, no difference
test and change CMOS battery, no difference

no matter what i do, i can't get video

the fans all come on and turn, and power is being sent to the
harddrive, keyboard, cd rom, etc

also, i get no beeps...the speaker is plugged into the motherboard,
but even with no ram installed, no beeps.

normally, i'd diagnose it as a bad motherboard, but this is the second
one for sure with the same problem, and another one is on it's way in
with similar problems...and they are all different boards (one is an
asus, the other is in a compaq)

any help, or ideas would be greatly appreciated
any information on something that may be targeting the video

If motherboard+processor+power_supply = no_beeps, then the processor
is not executing any BIOS code. This can be caused by bad caps
on the motherboard, frying the Vcore power source to the processor,
or on 875/865 chipset boards, the ICH5(R) Southbridge could be
burned, from ESD related latchup on a USB port. If the customer
managed to erase the BIOS chip, it won't beep either

It could also be caused by a bad processor, but the odds are much
lower of that being the problem. You could examine the processor
for signs of physical damage (customer induced, by bent pins, or
discoloration from the heat produced during a failure). Examine
the processor, if the test in the first paragraph above, has
failed to yield beeps.

Otherwise, you'll need to swap in a known-good-processor and
test motherboard+processor+power_supply again. If it still won't
beep, with a known good processor, known good power supply, and
unknown motherboard, then you know it is the motherboard.

You could also get a failure to beep, from a bad computer case
speaker. So, a double fault (some hardware failure, plus the
customer's speaker was bad), would complicate your analysis.
But since you have the symptom of no video, it isn't just
a bad speaker.

HTH,
Paul

 

[mattclarkes]

what can cause this though..

i now have seen 3 computers, all with the same problem, all wit
different motherboards..

is it power surge related, or is it possible for a virus to delete th
bios, and if so, how do you fix the bios if you can't get any video t
go to cmos or dos

 

[Paul]

what can cause this though...

i now have seen 3 computers, all with the same problem, all with
different motherboards...

is it power surge related, or is it possible for a virus to delete the
bios, and if so, how do you fix the bios if you can't get any video to
go to cmos or dos?

If you have another motherboard of the same brand and model number,
you can pull the BIOS chip from the "good" board and put it into
the socket on the "bad" board. Then try the "bad" board again and
see if it POSTs.

It is unlikely that a power surge would affect all three
computers the same way. If lightning had struck the equipment,
chances are there'd be some visible damage, smell, or other
signs of Mother Nature. If a man made surge, at least some
power supplies would die without taking the motherboard
with them.

If the motherboards have ICH5 or ICH5R Southbridge chips,
the damage could have been caused by static electricity.
I've noticed that postings about that failure seem to come
in bunches, and perhaps humidity changes with the seasons
might play a part there.

There are tons of motherboards still around from the
"bad cap" era, so that could be a reason. Brands with
a higher incidence of bad caps are listed here:

http://www.motherboardrepair.com/

As for viruses, I'm sorry but I'm completely ignorant on
the subject, and don't know if the BIOS has any protection
we don't know about or not. I thought at one time, there
was a BIOS setting that controlled whether the BIOS would
allow programming or not, but I don't see that in BIOSes
any more. And motherboards don't have a jumper to disable
BIOS writing either. So I have no idea how or whether
viruses are an issue there or not, or whether the BIOS
companies have some kind of protection code in the BIOS
itself.

If the three computer users have some relation to one
another (work at the same company), then a virus theory
might still be possible, but if the three customers
have nothing in common with one another, it is pretty
unlikely. I cannot say I've seen any postings about
BIOSes being wiped for no reason, so it isn't an
epidemic or we'd have heard something by now.

Do the computers share any common components, like the
same brand/model of power supply, or the same motherboard ?
If they did, then they might all have the same kind of
fault (like bad caps).

Paul

 

[Lawrence Lucier]

what can cause this though...

i now have seen 3 computers, all with the same problem, all with
different motherboards...

is it power surge related, or is it possible for a virus to delete the
bios, and if so, how do you fix the bios if you can't get any video to
go to cmos or dos?

Do you have an old monochrome/Herc video card and monitor.......they use
different addresses than the VGA and up; might be worth a try if you
do have them handy.

PS........thrift stores are a good source for picking up cheap testing
gear.

 

[Lawrence Lucier]

For the second time in a week, i've run into this problem...
computer comes in to be fixed, because they can't get anything on
their monitors.

Hi Matt..........did you get anywhere in resolving this issue with the
three computers? Kinda intrigued at this end of things as to what was
the problem.......

Ran across a really interesting discussion on a web site regarding
BIOS/Flash memory virii, though at this time I haven't had a chance to
do a little more digging on this subject.

Anyways just wondering.........ttyl

 

[mattclarkes]

still haven't solved the problem....
one was still under warranty with Future Shop, so they are going to
send it away....2-3 months time

and the other 2 are going to have to get new motherboards...as that is
the only solution i can come up with...

and really, with the price of mbs and cpus right now, it's not that
bad of an option...the hard drives and ram is fine...

if any one has a similiar problem , or finds a solution email me at
(e-mail address removed)

thanks, for all replies