mobo keeps shuitting down

[Gil Theissen]

I pulled out an old super socket 7 ATX system that ran fine when I put it
in the closet a month ago, but now
is acting odd. When I plugged the power cord in, it booted for 4 seconds
(one BIOS beep with POST on screen) and
then it shut down. After that, the board stays dead unless I do one of two
things: I have to either:
(1) unplug the power cord, wait a minute or two and then plug it in
again. Then it boots again for another
4 seconds and shuts down again. (BTW replugging the power cord in
immediately after shutdown does nothing -
apparently something?? takes a minute or so to reset); or
(2) Move BIOS jumper from 'on' (pins 1-2) to 'clear' (pins 2-3) and then
pull the jumper off entirely. As
soon as I pull the jumper entirely, everything powers up and runs
indefinitely. Pulling the jumper directly off the 'on' pins does nothing,
and leaving the jumper on the 'clear' pins does nothing (and I have no
documenteation about what removing the jumper entirely is supposed to do).
However, when the BIOS is first cleared and THEN the jumper is removed, then
everything powers up and stays running indefinitely. Nothing on the screen,
can't access the BIOS, but everything has power.

In scenario (1), after the board has shut down, the power button does
nothing, Switching the reset button to
the mobo power pins does nothing. Shorting the power pins with a jumper does
nothing. Power supply tested OK but tried another one anyway - nothing.
Tried a new CMOS battery - nothing. Unplugged HDD, floppy and CDROM -
nothing.
The HS/Fan runs fine, the board doesn't have an overheat shutdown feature
and at 450Mhz it isn't even
warm in 4 seconds. I know this 4 second shutdown sounds like the power
button is stuck, but as I said, it happens
regardless of whether the power button is connected or not and the BIOS
jumper routine has me baffled.
Any ideas would be appreciated - Gil Theissen

 

[Dave C.]

I pulled out an old super socket 7 ATX system that ran fine when I put
it in the closet a month ago, but now
is acting odd. When I plugged the power cord in, it booted for 4 seconds
(one BIOS beep with POST on screen) and
then it shut down. After that, the board stays dead unless I do one of
two things: I have to either:
(1) unplug the power cord, wait a minute or two and then plug it in
again. Then it boots again for another
4 seconds and shuts down again. (BTW replugging the power cord in
immediately after shutdown does nothing -
apparently something?? takes a minute or so to reset); or
(2) Move BIOS jumper from 'on' (pins 1-2) to 'clear' (pins 2-3) and
then pull the jumper off entirely. As
soon as I pull the jumper entirely, everything powers up and runs
indefinitely. Pulling the jumper directly off the 'on' pins does nothing,
and leaving the jumper on the 'clear' pins does nothing (and I have no
documenteation about what removing the jumper entirely is supposed to do).
However, when the BIOS is first cleared and THEN the jumper is removed,
then everything powers up and stays running indefinitely. Nothing on the
screen, can't access the BIOS, but everything has power.

In scenario (1), after the board has shut down, the power button does
nothing, Switching the reset button to
the mobo power pins does nothing. Shorting the power pins with a jumper
does nothing. Power supply tested OK but tried another one anyway -
nothing. Tried a new CMOS battery - nothing. Unplugged HDD, floppy and
CDROM - nothing.
The HS/Fan runs fine, the board doesn't have an overheat shutdown
feature and at 450Mhz it isn't even
warm in 4 seconds. I know this 4 second shutdown sounds like the power
button is stuck, but as I said, it happens
regardless of whether the power button is connected or not and the BIOS
jumper routine has me baffled.
Any ideas would be appreciated - Gil Theissen

OK, to me it sounds like your CMOS settings got lost due to a dead battery.
You have replaced the CMOS battery, but did you re-program the CMOS settings
to the way they were before the system went in the closet? If not, then you
might have a setting stored in CMOS that won't allow the system to boot
properly. I'd check, CPU, RAM, Video Card and Hard drive settings in CMOS
to see if there is something that isn't set right. -Dave

 

[Gil Theissen]

OK, to me it sounds like your CMOS settings got lost due to a dead
battery.
You have replaced the CMOS battery, but did you re-program the CMOS
settings to the way they were before the system went in the closet?

No, because I can't get into the BIOS in the 4 seconds before the board
shuts down again. The POST appears on the screen for about a half a second
and then the system powers off before I can do anything. Alternatively,
when I pull the BIOS jumper (scenario 2), the board does get continuos
power, but I still can't access the BIOS because the screen stays completely
black - no POST, no BIOS beeps, nothing but whirling fans.

Gil Theissen

 

[Dave C.]

No, because I can't get into the BIOS in the 4 seconds before the board
shuts down again. The POST appears on the screen for about a half a second
and then the system powers off before I can do anything. Alternatively,
when I pull the BIOS jumper (scenario 2), the board does get continuos
power, but I still can't access the BIOS because the screen stays
completely black - no POST, no BIOS beeps, nothing but whirling fans.

Gil Theissen

OK, try this. Put the CMOS jumper in the ON (not clear) position. Unplug
the system. Remove the CMOS battery. Leave the CMOS battery out for about
a half hour, then reinstall. Then try getting into BIOS setup to check your
CMOS settings. -Dave

 

[Gil Theissen]

OK, try this. Put the CMOS jumper in the ON (not clear) position. Unplug
the system. Remove the CMOS battery. Leave the CMOS battery out for
about a half hour, then reinstall. Then try getting into BIOS setup to
check your CMOS settings. -Dave

Thanks, but no difference. Same symptoms.
Gil Theissen

 

[Bob M]

Thanks, but no difference. Same symptoms.
Gil Theissen

I had this problem once with an Epox board and an AMD 2200+. I ended up
removing the heatsink and CPU. I then reseated the CPU and reinstalled
the heatsink. Clean the CPU and heatsink before reinstalling. System
booted right up after that. CMOS jumper in the "on" position. Worth a
try in your case.

Bob

 

[Jan Alter]

Ready,
Go to the boardmaker's website and check for an updated bios. If they
have one flash it. If they don't download the latest and flash your mb with
it (following the board maker's installation procedure exactly). Oh, I must
be mad to suggest that.

Here's my reasoning for such a measure. I have an Abit Kt7 raid board
(currently I'm not using it). Actually that board is pretty famous at this
point in history, but anyway, about a year and a half ago I decided to
install XP on it after running Win 98 for the previous two years. Even
though I changed the boot order in the bios to start with the CD-ROM I could
not get it to start. It simply floundered and then displayed that there was
no OS. Do understand that with this exception the mb worked just fine for
the entire two years I'd used it and was very stable and dependable.
Abit had issued probably six new bios versions since I'd owned the board
and I never flashed it because I had no need, being that I was having no
problems. To make this longish story short after downloading and flashing 3
or 4 newer bioses I downloaded the very latest bios, flashed the board and
to gratification's sake the board booted the WinXP CD to allow install.

 

[Gil Theissen]

I then reseated the CPU and reinstalled the heatsink. Clean the CPU and

heatsink before >reinstalling. System booted right up after that. CMOS
jumper in the "on" position. Worth a
try in your case.

Thanks but I already tried a new cpu and hs/fan - no difference.

Go to the boardmaker's website and check for an updated bios. If they
have one flash it. If they don't download the latest and flash your mb
with it

Thanks, but I'm at a loss to understand how I can perform a flash when when
my system powers down four seconds after I power up. It doesn't matter
whether there's a bootable floppy in the drive or not. It still turns itself
off.

Gil Theissen

 

[Jan Alter]

Thanks but I already tried a new cpu and hs/fan - no difference.

Thanks, but I'm at a loss to understand how I can perform a flash when
when my system powers down four seconds after I power up. It doesn't
matter whether there's a bootable floppy in the drive or not. It still
turns itself off.

Gil
Theissen

when the BIOS is first cleared and THEN the jumper is removed, then
everything powers up and stays running indefinitely. Nothing on the screen,
can't access the BIOS, but everything has power.

Sorry, I had the thought that if you were using a bootable floppy with the
flash utility and bios file you could actually boot and flash.
Have you tried reseating the graphics card? If you have another card I'd
try a substitution as well.

Jan Alter

 

[nope]

If you have another power supple, try that. Sounds crazy but it worked for
me once. Drove me nuts.

ALso did you replace the CMOS battery? I don't remember if you said so.

And also, did you use compressed air to clean it when you took it out of the
closet? If it was any kind of moist or dusty, that could have done
something.