Strange Real Time Clock fault - any hardware experts out there?

[Bill Mayhew]

The author didn't say exactly how the clock stopped on the PC6300.
If the clock seems to freeze at a certain time without going to
zeros in all registers, the problem is most likely that the nicad
battery is not supplying sufficient voltage for proper operation.

In most cases the battery cuases problems when the PC6300 is used
less than a few hours a day.  One solution is to compute more.
Another fix suggested by an AT&T service rep is to just leave the
machine on overnight every now and then to make sure the battery
gets a full charge.  In extreme cases, it is best to replace the
battery.

--Bill