[vox-tech] CMOS problems, dead battery?

ME vox-tech@lists.lugod.org
Tue, 23 Apr 2002 16:30:13 -0700 (PDT)


Static discharge/short in mb (temporary or on-going)

BIOS/CMOS EEPROM receives bad signal.

Uncommon, but possible on some systems: nvram/BIOS access from OS altered
 things. There are viruses that can target data stored in nvram and make
some machines unbootable, but that are rather uncommon.

Non-power supply related:
Someone set a jumper on the mb imporperly.
After successive heating and cooling "chip rising" (not so much a problem
 on modern machines - mostly with older DIP chip based boards with bios in
 sockets instead of integrated.)
Bad contact / intermittant contact with chips used for BIOS
Dead battery or battery getting close to being dead (mentioned by you
 earlier, but still most common.)
Failure in chip holding BIOS data
Introduction of UV Radiation or open photoport for EPROM and light cause
 damage/erase (Is any vendor using EPROM for BIOS anymore?)

These were off top of my head.

I'm sure there are others. Any EE majors/graduates out there?

-ME

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On Tue, 23 Apr 2002, Ryan wrote:
> Anything other then a dead battery that'll cause a CMOS checksum error
> after the computers been off AC for a little while?