[vox-tech] CMOS problems, dead battery?

[ME]

On Tue, 23 Apr 2002, Ryan wrote:
> On Tuesday 23 April 2002 04:30 pm, ME wrote:
> > Someone set a jumper on the mb imporperly
> 
> Perhaps, but most motherboards refuse to boot if the CMOS clear jumper is 
> set, and that's about the only jumper on the board (everything else is in the 
> bios)

It is rare, but possible. I dont remember the last time this was an issue
(over 8 years though.)

> > 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.)
> 
> I dislike intergarted BIOS, makes things much more expensive if you botch a 
> flash. (this happened with my laptop, costing me $150 for a new motherboard 
> instead of $15 for an new BIOS chip)
> 
> The one on the affected system IS socketed, and is fairly new. I thought most 
> desktops were like that.

Certainly. My mistake. Even though modern machines are built with sockets
for BIOS chips, it seems those built now do not suffer from "chip
rising" so much as the previous ones made 2+ decades ago.

Having socket based BIOS is a good thing when they are EEPROM based and
you can flash oiver to a new version, but bad when they are EPROM based or
just plain ROM as you have to get them via mail-order.

I agree with you on the risks of having the firware/FlashROM
integrated. 

> How long should a battery last?

It *should* last forever, but rules on energy, perpetual motion machines,
rules of thermodynamics seem to stick their tongues out at me for wishing
for it.

Common lifetimes for batteries on systems is quite variable and can
depend, on some systems, on how much time it is spent witout any AC
power. (Some seem to use AC power when available - even when the system is
powered off, but when unplugged use only the battery.)

To the answer... from 3 to 8 years seems common. (I have seen more and
less, but this range covers most machines.) 5 Years is a safe bet for most
machines before replacement is needed. Less than 5 years, you may want to
check to see if there is a short in you mb somewhere that could drain the
clock. (High resistance short for slower drain for example.)

Hook up a voltmeter/ammeter to the battery and see how "alive" it is. That
is one way to test the battery and try to rule it "out" or "in".

-ME

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