Any idea what the specs are, or the P/N of the backup
battery is? I
have a MP120 that throws an error about the backup battery every time it
powers up. Works fine, though, and isn't losing data when powered down.
The backup battery only does its thing when the main batteries are dead
(or removed for changing).
It should be a user changable part in the battery compartment. On the 100
and 110 it is just a standard button cell battery (I think I bought my
last replacement one at Rat Shack)
The 110 in front of me uses a CR2032 battery (large button cell, 3v
lithium).
As long as the 120 isn't missing its battery, you should be able to just
remove it and read the numbers off the back of the battery. If it is
missing, it is probably the same battery as the 110, since the 120 was
built around the same design (110, 120 and 130 were all "sister" units...
the OMP and 100 were sisters, and the 2000, 2001 were sisters)
-chris
<http://www.mythtech.net>