The Model 50 with a calendar mechanism added. A finger on the date wheel moves the date ring, a detent spring holds it and helps carry it, and the date can be set by hand in either direction.
The Timex Model 51 is an electronic calendar movement, the same as the Model 50 except that a calendar mechanism has been added. The date can be set manually, either forward or backward, by rotating the hands.
The one difference in servicing: Basic servicing is the same as the Model 50, except that the minute hand should be removed prior to removing the dial. See the Model 50 guide for the electronic movement.
Caution: Since the watch contains permanent magnets, no attempt should be made to demagnetize it.
Everything below the numbered parts is the Model 50 electronic movement.
Model 51 · Exploded View
145Dial Rest
206Center Wheel Assembly
498/1Hour Wheel Washer
751Dial
850Hour Hand
851Minute Hand
852/1Sweep Second Hand
2556Date Wheel Assembly
2557/1Date Ring
2558Hour Wheel
2576Detent Spring
The Date Mechanism
1 · How It Drives
A finger attached to the date wheel assembly engages with and moves the date ring.
A detent spring holds the date ring in position and also aids in moving the date ring.
A pinion attached to the hour wheel, 2558 on the exploded view, engages with the date wheel assembly.
Note: Use the exploded view as a guide in disassembly and assembly of the mechanism.
Fig. 51.3 · Date Mechanism
Cleaning & Lubrication
Dial rest, July 1976: the same spreading type lubricant used on the Model 254 (Woods AAAA oil) may be applied to dial rests which have solid film lubricant, between 3 and 6 o’clock on the inside corner. Service Bulletin No. 112
Lubricant change, June 1974: Timex Service Bulletin No. 111 replaced the factory oil for this model. Moebius Synt-A-Lube oil is used instead of Elgin M56B oil. (It supersedes Bulletin No. 108.)
All cleaning and lubricating points indicated for the Model 50 should be followed for the Model 51. In addition, lubricate a few teeth on the date ring and the post of the date wheel. The dial rest has been coated with a solid lubricant and needs no further lubrication.
The date ring is a printed dial: Some watch cleaning fluids will strip the printing.
Positioning the Hands
1 · First
First: set the finger on the date wheel assembly against the date ring as shown in the figure above.
2 · Next
Next: replace the dial assembly together with the hour hand, keeping the hour hand set at the 2 o’clock position.
3 · Finally
Finally: replace the minute hand and sweep hand.
This guide is based on the original Timex factory service manual for the Model 51 movement.
