Garmin III+ Date Frozen

I replaced the internal battery on my Garmin III+ a few weeks ago and since
then, the date is frozen on March 31, 1992. Can anyone explain this and/or
provide a means to do a full reset on the unit to see if that clears the
issue?
Thx,
TL

http://www.gpsinformation.org/dale/secret.htm offers a reset method.
Whether this will get your unit behaving is something you will have to
determine.

or "Hard reset" - hold down the PAGE button while powering up. (at
your own risk)

Thanks. Sure would be nice to know what got me here in first place, though.
Probably never know.

The internal battery supports volatile memory, which if scrambled can
cause a variety of aberrant behaviour. My II+ has at various times
given me the absolute heebiejeebies trying to get sense out of it, and
only_sometimes will a hard reset give it the bitch-slap it needs to
smarten up.

My Nuvi760 (which has replaced the II+ for all roles except NMEA data
streams) did a total fu\lockup once, and wouldn't boot up or even
reset. Somehow persistence paid off and eventually it saw the light.