Intermittent Boot Fail

[Debbie]

I have just built a system around a 478 Intel CPU. On a AOpen MOBO.

I can reboot the system over and over again without fail but sometimes it appears that
when left for some time (minuits to hours) for some reason it will beep once and fail to
boot.

Usully pressing and holding the reset button while frozen will clear the problem.

There are no problems when it gets going.

Any ideas ?

[az]

PSU. Also check mainboard caps.

[Debbie]

Thanks az. It appears that the PSU is OK because I have no problems when the system is
going. Also the LEDs remain on when it fails to boot.

mainboard caps ? Can you explain ?

[Helevitia]

I had a mobo that would do that. It was a BIOS bug. Nothing I could do until they fixed it.

[Gurm]

I had a system once that only booted 1 out of 3 times, but when it did it was rock solid and TWICE as fast as everyone else's system.

...

...

...

Ok, it was an A20 "x8086-compatible". And it was clocked up with a crystal I ordered from Taiwan. But that thing kicked 286's ASSES.

[Marshmallowman]

Intermittent boot failures really IS typical behaviour for bad/failing PSU's

I would test an alternative PSU if you can.

I think Az means check the capicitors on the mainboard for signs of leakage, those little plastic cans have a eloctrolytic solution in them and when the fail the typcially ooze dark stuff.
If they are leaking its eityher new mainboard time, or you can try your luck with a soldering iron and some replacements

[Debbie]

Thank you guys. This is an old but brand new MOBO. I had a look at the electrolytic capacitors and they all appear to be healthy. I can't change the BIOS because I already
have the last and final version.
I left it overnight and this time it stoped on the XP Microsoft logo.

[Chucky Cheese]

...i just helped a friend through a problem like yours...it turned out to be a bad memory module

cc

[Debbie]

I'm using brand new (just purchased) Corsair PC400 DDR with lifetime warranty.

[az]

You really have bad luck with computers lately, don't you?

Even brand new brand name RAm can be faulty. Since your system does make it to the windows boot screen, I don't think it's the PSU or the mainboard capacitors. That is, rereading your first post still makes me think it's either a PSU problem, bad capacitors (they don't have to be leaking, they might only be bulging - their tops must be flat!) or a thermal problem (system's OK when warmed up because some bad solder joint or something gets proper contact when things expand when they get hotter).

You COULD try reinstalling Windows if you haven't done much yet - although the behavior you mentioned in your first post suggests it's something before the OS is loaded, so there must be something wrong with the hardware. The freezing when it's already started to boot (showing the XP logo) - does that happen often? It might be unrelated.

[Debbie]

Yes true az about bad luck. I just had to buy what was available, as regards a MOBO and
CPU.

I just want to keep using my existing video capture cards Asus (Radeon) 9600xt and the
ATI A-I-W 9800SE.

Actually this MOBO and processor is a backup for my 2 PCs with ASUS MOBOs. If any one
of these dies I would have a replacement. Not a good one, from it's behavior, but better
than nothing.

I could reboot sevral times before it hangs on POST and most of the time hitting the reset
button gets it past POST.

BTW, this is the same BOBO that its manual says that it is suitable for Northwood and
Prescott CPUs only to find out that it will not take a Prescott. AOpen is at least for
me.

[az]

Actually I think just living with the problem might be easer than trying to fix it - if it works well once you've got it to boot.

[Debbie]

Yes az, It's more of a nag (as it is) than a problem actually. Infact I'll just put back my
original ASUS MOBO and CPU even if they have lesser specs. and leave this as a backup.

[Debbie]

I'm reviving this thread because I finally discovered the fault. A bad PCI slot !!!
It started as an intermittent fault and just yesterday it died. The rest of the slots are fine.