I'm on my 3rd Casio TeleMemo 150 in 10 years; newest one about a year
old. All have differed in tiny construction details inside, but all
have had a trimmer capacitor for regulating. As have all the Casio
watches belonging to others in which I've changed batteries. The
trimmer is marked with a screwdriver blade symbol on the CRS shield.
Although there is surely a test point to access the oscillator, I've
adjusted mine by trial and error to about 1 second/month. In the
TeleMemo 150, counterclockwise on the trimmer seems to be frequency
increase.