13.007 How do I replace my GS "BatRAM battery"?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
13.007 How do I replace my GS "BatRAM battery"?
The standard GS battery is a 3.6V Lithium type rated at 1.2AH. It is
called the "BatRAM" battery because it keeps the Battery RAM and Clock IC going
when you turn OFF power. To get to the battery, you must disconnect the AC cord
and pop out the Power Supply.
If you have a ROM 03 GS, you can slip out the old battery and slip in 'one
like it'. On the ROM 01 GS, you will need a Lithium battery with leads you can
connect to cut-off leads from the old battery-- about 3/4" each for most
connection methods-- remaining on the motherboard. Be sure to mark the "+" lead
on the motherboard with white-out.
Night Owl Productions used to sell a convenient "Slide-On" Lithium battery
made by Tadiran. It came with springy ends that would slip over the cut-off
leads from the original GS battery.
Radio Shack sells a few models of 3.6V Tadiran Lithium batteries. Mostly,
these have smooth ends and are intended to fit into a holder-- for example, one
model is "AA" size. Connecting an insulated size AA holder and using a size AA
3.6V battery is one way to handle BatRAM replacement now while making future
replacements easier.
Another Radio Shack 3.6V Tadiran Lithium battery comes as a small
rectangular insulated pack with red and black wires going to a plug. From the
catalog illustration, it appears that the plug could be fitted onto the cut-
off leads if these were long enough to be shaped to match the plug's
connectors. (If you decide to have long cut-off leads, it's a good idea to slip
heat-shrinkable tubing over the leads to insulate them for most of their
length.)
It may be that your best bet for getting a good BatRAM replacement battery
is All Electronics (800-826-5432; http://www.allcorp.com ). Their catalogs
often list 3.6V lithium batteries with and without wire leads in various sizes
at low prices.
If you like, you can always solder, crimp, etc. insulated leads going to
some plug or socket which matches the connector of a particular battery you'd
like to use. Whatever, make sure that the new battery's "+" lead connects to
the "+" lead on the motherboard.
For connecting solid wire bare leads, you can use the spring connectors
from a Radio Shack electronics experimenter kit or just wrap the new battery's
leads around a large sewing needle to make them springy. The springy leads can
then be slipped over the cut off leads on the motherboard. Another non-
soldering approach is to use "wire nuts".
Should you do any soldering to the cut-off leads, use good quality rosin
core solder (e.g 63 Tin multi-core) and try to avoid long heat exposure. You do
not want to melt the connection at the motherboard. Similar concerns apply to
soldering to the new battery leads. With good solder and clean leads it should
be possible to "tin" each lead and make the connections in a few seconds for
each operation.
Especially if you are joining bare leads to bare leads, you could end up
with more bare wire than you are comfortable with. Check that the bare leads do
not touch anything they should not. Bend the leads as required and position the
new battery so that nothing will bump into the Power Supply when it is
replaced.
The usual recommendation for this kind of work is that the computer be
OFF. This reduces the risk of damage should a bit of solder, a wire, etc. fall
onto the motherboard.
When disposing of the old battery, snipping off its leads at the battery
to reduce the chance of a direct short is a good safety measure. It's hard to
be sure an old battery is completely dead; and, a direct short could produce
enough heat to burst the battery and/or start a fire.
GS users are sometimes shocked to discover that a replacement battery may
cost $8 to $13. This has led to suggestions that 2-3 standard 1.5V cells in a
holder be used. While any number of lower-cost replacement setups can work,
this is pretty close to a classic 'you get what you pay for' situation. Regular
1.5V cell combos reportedly crater in about a year. A 3.6V 1.2AH Lithium
battery is routinely good for at least 5 years.
Our old Nite Owl battery is going on year 8 or 9. That's a lot of years
without having to worry about burst and leaking cells or needing to pull the
Power Supply and mess with swapping-in replacement cells.
By: Rubywand, Duncan Entwisle, Jerry Cline, Bruce Baker
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