[GRLUG] BIOS problems - Round 2

[Tim Schmidt]

Well, I've had a little time to think about it, and here are some more
thoughts...

Without more information, I cannot say what caused the board to stop
working.  I can say that (short of bad capacitors:
http://en.wikipedia.org/wiki/Capacitor_plague and dirty power)
motherboards generally do not stop working when left alone.

I suspect that after you removed the battery for some time, the BIOS
was reset, and the board is now trying to post from a PCI graphics
card (often the default).  However, here's a blow-by-blow of common
issues.

RAM can stop a machine from posting if the timing values in the BIOS
are too agressive or, more rarely, if the RAM is of a configuration
incompatible with the motherboard chipset (think 256Mb high-density
dimm in an i440 BX motherboard).

CPUs can keep a machine from posting if they are not supported by the
current BIOS of the motherboard (reguardless of the board's
theoretical ability to support such a CPU).

PCI, AGP, ISA cards can keep a machine from posting with buggy BIOSs,
interrupt conflicts, poor seating, dusty contacts, excess power draw
(especially in the case of newer graphics cards), slightly out-of-spec
clock timings (especially in the case of overclocked machines -- some
motherboards slightly overclock automatically), or cards and
motherboards explicitly not supporting each other (as in a PCI 2.1
card in a PCI 1.0 board or an AGP 8x card in an AGP 2x board (this
generally works, as most cards are capable of backing down, but not
always -- and further BIOS interactions can complicate things)).

External peripherals like keyboards, mice, monitors, printers, USB
gadgets etc. can keep a machine from posting.  Circumstances are
generally odd, unfortunate, and rare, however.

Drives can easily keep a machine from posting, by being configured
improperly, cabled improperly, or paired with other drives that don't
like them.  If you'd like more detail on this I can flesh it out
sometime soon...  PATA drives are a dying breed however.

And the whole damn lot is subject to grounding problems, possible
shorts, power supply issues, etc.

--tim