It looks like the upper page is the testing when it arrived for repair. They hooked it up to a timing machine and this is the readout before they adjusted/fixed it (I assume). The s/d is really all you need to know, and that is the number of seconds it was off per day. The CH, CB, 9, 6, 3, 12, refer to the position the watch was in when the reading was taken. Simply put: gravity affects mechanical watches and will affect their accuracy if the watch is placed dial down, dial up, or on it's side with the crown up, down, or at 12 or 6 (which is what the 3, 6, 9, 12 refer to). This often why mechanical watches are advertized as "adjusted in 6 positions" as they are meant to keep time no matter how the watch is positioned, such as when you take it off at night and put it on its side on your night stand. The D is the range of s/d and X is the average. So in the upper sheet your watch lost an average of 86.3 s/d (and has a high range depending on what position the watch was in--like if you left it crown facing up, it would lose 92.8 s/d) and in the lower sheet your watch, after adjustment, gains 8.4 s/d but with a much smaller range of 8.1 s/d. Offhand I don't know what Di and DVH stand for.
The amplitude is a metric that tells you the angle of the "swing" of the balance wheel (think of it like measuring the angle in a grandfather clock pendulum as it swings from its axis). The balance wheel is what gives the watch its accuracy; it is like a round "gear" that rotates in one direction then rotates in the other that causes second hand to move--amplitude measures this rotation of the balance wheel in degrees. Too small an angle--it's not rotating to its fullest--and it would indicate that the lubrication is breaking down; too much of an angle--over rotating--would indicate the mainspring (that powers the balance wheel) might be too tight/powerful. Most watches have a range of amplitudes between 250-300 with 270 being the sweet spot. The beat error is the difference in the amount of time it takes for the balance wheel to swing in one direction relative to the other direction (sort of like if the pendulum took longer to swing in one direction than the other...this would indicate something is off).
Last edited:
