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Seiko 7A38 Qyartz Chrono

2K views 5 replies 3 participants last post by  kohym 
#1 ·
How can we tell that this movt has 15 jewels?:-s
 
#2 ·
Look at the specs?

The Sekio 7A movements were nice early quartz. I have a 7A28 that's fully jeweled and made of metal. 15 jewels is probably enough for a good quartz chrono. On mine the case has had a hard life but the movement still works fine.
 
#5 ·
The gear train in a quartz watch has less need of jewels... in a quartz watch they are just a drive train for the hands and have no effect on the timing.

When quartz was first introduced it would have been 'a hard sell' to convince people to pay more for a quartz than for a mechanical if the quartz had no jewels. (Yes, when introduced quartz were often more expensive than mechanical counterparts.) This because people had been trained to believe the more jewels the better the watch.

So early quartz have a lot of jeweling.

Jewels are still useful for a quartz watch and will extend the life between servicing. So they still have them in the better quartz movements. But many effective and efficient quartz movements today have zero jewels.
 
#6 ·
:-!thanks all for advice:thanks

i finally pulled trigger on a NOS gold plated 7A38-7190. comes with original manual and g'tee booklet way back to 1985! also has original hang tag but box was not a seiko quartz box but a old plastic seiko box.

will post pics here & on blog soon:thanks

I am so happy I bought a piece of seiko history!
 
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