Sur le site Perpetual, il y a le mode d'emploi pour le mouvement GMT. Voici le lien : http://perpetual-watch.com/files/GMT_Instruction_Manual2.doc
Je reproduis le texte ci-dessous (en anglais) :
GMT INSTRUCTION MANUAL
1. WINDING POSITION
2A. QUICK-ADJUSTING THE DATE
-by turning the crown clockwise
(adjustment cannot be effected between 21:00 hr - 1:00 hr)
2B. QUICK-ADJUSTING THE 2nd TIME ZONE
-by turning the crown anti-clockwise
-When finished setting the GMT arrow-headed hand, you will realize the GMT hand will either behave normally or will un-usually hop forward (about 10 minutes). It is a good thing if the hopping motion does occur since the GMT hand will synchronize with the Hour/Minute hands in just a while (10 minutes). On the other hand it will require to pay extra attention to the GMT hand time setting when the GMT hand behaves normally (no hopping), you have to reset the GMT hand one more time, and this time make sure to add extra 10 minutes to your desire GMT time setting before pushing the crown back to position 1, this way the GMT hand although has been adjusted 10 minutes in advance but it will synchronize with the Hour/Minute hands soon afterwards (10 minutes).
Due to the complexity of this SH RK4D movement caliber, it is difficult to predict when the GMT hand’s hopping will occur or not. It will be just fine to make sure to reset the GMT hand once again when there is no hopping occurred. Actually the best way for setting this GMT watch is first to set the Hour/Minute hands, then push the crown back to position 1, pull the crown into position 2 to set the GMT hand according to the above mentioned hopping behavior in order to have the GMT hand set correctly & precisely.
Additional Hints
The setting mechanism of this GMT movement is best maneuvered this way,
once setting of the Day or GMT is done or the Hour/Minute setting, always return the crown back to position 1, then pull the crown into position 3 to set the Hour/Minute hands, otherwise, it will always be a bit difficult to pull the crown from position 2 into position 3, or vice versa.
Amitiés,
Abbazz