Seiko Grand Quartz

cal. 9943

Factory Spec. 10 SPY

Thermocompensated: Dual Oscillator (32 kHz + unknown)

User Adjustable: Yes

grand quartz 

The frequency of the auxiliary oscillator is not known for sure, but based on a comparison of power requirements between the various Twin Quartz watches in my collection, I believe it is reasonable to assume that the frequency is 40 kHz.

UPDATE - I have sold this watch.

Some details for this watch may be missing as it was subjected to comprehensive testing.

Parent Company Seiko Holdings Corporation
Brand Seiko
Model Series Twin Quartz
Model Name Grand Quartz
Model Number unknown
Case Number 8020
Serial Number 8D0455
Approx. Date of Manufacture December 1978
Calibre (mvt maker) 9943
Calibre (brand) 9943
Factory SPY 10
TC Appproach Count adjustment & twin quatz
Frequency (XO 1) 32 kHz
Frequency (XO 2) unknown (40 kHz, assumed)
Rate Adjustment User
Major Inhibition Period unknown
Minor Inhibition Period unknown
Power Disposable cell
Cell Number SR927SW
Case Back Cell hatch
Water Resistance unknown
Features 3-hand, no numeral dial
  Day, date (not perpetual)
Timing Results Basic data  &  Further details
Images Photos - Large File Sizes!