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Seiko 2205-0240 Teardown

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This evenings victim is a Seiko from December of 1970. The only issue other than being a daily wear for some mod rocker back in the day is the crown has no click. Winding, time and date changes as normal but something is amiss in the keyless work.



My fabulous-ly inexpensive tool for unscrewing casebacks will not shrink small enough to capture the grooves so a moments thought and some rearranging of the bits allows us to get started.


Checking the inside of the back for service marks shows no entry, screw heads seem undisturbed by other rookies such as myself and of course I have forgotten to set the time to allow easy removal of the hands. Reinserting the crown and stem and using hand pullers with plastic bag leaves the dial in pretty good shape even with my clumsy handling. 






Of course you folks see it although I didn't: the adapter ring is still around the movement barring access to the dial feet screws. Looking around we see two screws at the tip of the tweezers that look like they will do the job. Sure enough the ring drops away and the foot screws can be loosened on either side of of the dial. 






Removing the dial while looking for a washer underneath we see the broken spring end laying on the date wheel. Of course all this manipulation without a movement holder will probably cause more trouble later. But at least without the dial getting squished we now secure this tiny movement a little more properly.




Removing the weight reveals the winding mechanism. Depressing button just above the crown allows stem to be replaced, then held while holding the click just below the stem to take the small residual power away after all this abuse. Amplitude seems quite minimal but not unexpected since I've probably squished things pretty good a few times up to this point. 

Feeling pretty intimidated at this point, put everything away until tomorrow night. See you then!

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  • 2 weeks later...

The click on these is Seiko's typical sheet steel. I had a 4205 (similar except the 4205 uses a balance bridge, not a cock) where the part the holds the ratchet wheel was worn and not holding back the ratchet wheel. I gently bent the click into a 'V' shape to bring it in closer and problem solved. I usually have organ donors for other Seiko movements but not for these.

Something you might consider if yours is similarly worn.


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