15 Jul 2015, 21:32
I correct myself here... In this instance, it IS possible to tell which module you have, without even seeing the front of the watch. The parallel, three-finger battery contacts are the giveaway; you have a 201-2 (vertical light sensor) module in this watch. 201-1s also have a three-finger battery contact, but in either pinwheel or fan-blade style (a variation discussed elsewhere). So, just as well you did not disturb a working watch (you should be aware of the possible danger static electricity poses to opened watches; this early CMOS circuitry is very sensitive, and can be instantly and permanently damaged by voltages above 15V, and static charges can carry hundreds or even thousands of volts). When changing batteries, you should make sure you are grounded, or work when it is raining or foggy (static charges cannot form under conditions of high humidity...>70%).