It's an RC oscillator circuit. The schematic shows an adjustable resistor.
None of my units have that--there is a fixed resistor. I cannot tell what
the value of the capacitor should be...guessing 60pF?

I forgot to mention--in my working toys, the clock still appears to wander,
but much less severely. It seems to fluctuate based on whatever the
microcontroller is doing.

Lacking in-depth experience with these circuits, I also want to be sure
whether I'm on the right track or not.

William