MST 900,  901,  902 
Ligne12.5''' 12.5''' 12.5'''
Cal. MST 900

Remarks: This was one of the first commerical quartz movements. It is a fascinating movement with a conventional escapement, but instead of a balance wheel or more conventional quartz stepper motor, uses a quartz controlled anchor/lever with conventional pallet jewels. The anchor is attached to a heavy iron which when subjected to a magnetic field moves the anchor some side to side. It has a significant tick, as the lever hits the buffers. Don't be misled by the use of plastic in the dial plate, for a watch using electric components this is simply sensible - as seen in the Accutron amongst others. The movement is otherwise heavy and well constructed, with 7 jewels, and all non electronic parts are servicible and likely to last indefinately.
Quite rare, and also seen in versions sold under the Seth-Thomas brand.
A word of caution when purchasing non functional movements - even if in fine condition when laid aside, the lower pivot of the anchor will rust and as it is soft iron and very fragile is insanely difficult to remove intact. These parts are no longer available. An excellent writeup on these movements is available at crazy watches
Production period: 1972

Jewels: 7
Beat: 32768
Winding: Battery
Manufacturer: MST
Hand sizes:

MST 900 12.5''' (28mm) First quartz, with traditional lever escapement
MST 901 12.5''' (28mm) Date, first quartz, with traditional lever escapement
MST 902 12.5''' (28mm) Day and Date, first quartz, with traditional lever escapement

Common parts/Interchange
Watches in my collection with the MST902:

All text and images are either © Kris Bubendorfer 2011-23 or © Roamer Watch Company.