Question:
My Apple IIgs no longer keeps correct time and date.
Answer:
You need to replace the logic board's back-up battery.
This battery is a 3.6 volt Lithium 1/2 aa type. Locally, I've been able to
get them from Batteries Plus and Battery Factory at less than what Radio
Shack asks. The local Apple dealer may also have them for less; it is a
common battery used by many current Macintoshes.
If your IIgs logic board is ROM 1 (256k), then the battery requires leads,
which are very hard to come by nowadays. The cleanest way to deal with this
is to clip the leads of the old battery as close to the battery's body as
possible, leaving the leads still soldered to the logic board. Then, on the
new battery, rough up the area where the leads will be soldered with a file.
Using solder paste, now put a blob of electrical solder on each roughed-up
place. Move the battery over to the place where it will be soldered onto the
old leads orienting it to correct polarity (a + and - are printed on the
logic board for reference). Solder first one, then the other lead on and
you're good to go. Something to hold the battery steady while putting the
blobs of solder on will be useful, too.
The IIgs ROM 3 (1 megabyte) logic board has a battery holder and will only
require removing its cap to replace the old one.
