23 Mar
1998
23 Mar
'98
7:53 p.m.
This is a great idea, but after scrounging around, I got a replacement
for about the cost of this workaround. I found one place that wanted
$20
but finally found a Radio Shack that had one for a lot less. The
battery still cost a lot more than the PC/AT!
Thanks,
Dave
Tony Duell wrote:
I picked up an original PC/AT that has a dead lithium battery for the
CMOS bios parameter storage. The battery says it's 6.8 volts. It's the
kind that is a 1/2x1x2 inch pack with a six-inch lead.
I've tried several places to find a replacement, but either a store
doesn't have it, or, if they have one, the voltage is not exactly 6.8
volts.
So, what's the acceptable voltage range, especially on the low end? And
any good sources?
Well, the voltage is not that critical.
I also have a PC/AT (original type 2 system board), and the battery in
that was dead when I got it. It claimed to be a 6V battery. I managed to
find a place to buy a replacement, but it was \pounds 14.00 or something
equally crazy, so I made a replacement :
1N4148
+------->|------+----------( +ve
| |
----- /
--- \ 100k
----- /
--- \
----- |
--- |
----- |
--- |
| |
+---------------+----------( -ve
The battery was 4 AA alkaline cells in a standard holder. The diode/resistor
were added since 4 fresh cells gave about 6.6V, and I was worried about
killing my RTC chip. In theory it'll cause the battery to run down a
little faster, but mine's lasted about 4 years so far. I cut the cable
off the old battery and used that to connect my kludge to the system board.
And next time it fails, 4 AA cells are a lot cheaper and easier to find
than the official battery.
Thanks,
Dave
-tony