From the technical manual:
“Using the ACCUSET Corrector“
After a period of time, if the watch is no longer accurate to the exact second, press and release thevACCUSET button the instant the time stenderd used naches the 60th second (12 o'clock) marker. (Maxi-um correction is + or - 30 seconds.).
The sweep second hand of the watch will temporarily stop if it is fast, or accelerate if it is slow until it is in synchro-nization with the time standard..
In order for this to work correctly the system must be set correctly by the watchmaker after a battery swap. as follwos:
How to calibrate after battery swap:
Setting Instructions
Step 1. When sweep second hand of the watch
reaches the 60th second mark (12 o'clock marker),
pull crown out to Position 3 (See Fig. 5,).(Allhands
will now stop.)
Step 2. Press and release ACCUSET button.
(ACCUSET circuit is now synchronized with position
of second hand.)
Step 3. Turn hands forward until date changes. (This
establishes midnight.) .
Step 4. If A.M., advance hands 5 minutes ahead of a
time standard being used. Then gently turn the
minute hand back to correct time.
If P.M., advance the hands past 12 o'clock (noon)
to 5 minutes ahead of time standard and then gently
turn the minute hand back to correct time.
Step 5. When time standard being used reaches the
60th second mark (12 o'clock marker), push crown to
the "intermediate" position (Position 2). All hands
will start instantly.
Step 6. First set the date, then the day. Crown must
remain in Po'sition 2. Slowly turn crown forward to
correct date; backward to correct day. Push crown
"in" (Position 1).
Note: Day Indicator is printed in English and
Spanish, or English and French. Set accordingly.
Calendar cannot be set manually between 9:00
P.M. and 1:00 A.M. However, the mechanism will not
be damaged if crown is accidentally turned during
this period of time.
Additional Setting Information
Once the ACCUSET circuit has been set (Refer to
Step 1 and Step 2), there is no need to reset it,
unless the power cell has been removed, or there
has been an interruption of current.