Hard to believe it was only this year I started on this one, seems like it was ages ago.

After doing a lot of research and gaining experience on Seiko 6 series movements, I think I'm getting the hang of tuning them.

I currently have four 6309s on a power reserve test. All have been serviced and jewelled (barrel arbor jewels) and put on my new Cyclotester to wind them (rather than my dodgy watch winder box).



Amplitude at full wind ranged from 235º to 265º across the four and as of this moment, they are running nicely (forgot to check them at 12 hours). Mainsprings used are a Generale Ressorts generic (for the ETA 2892/4) and Seiko mainsprings. The only one definitely a 401615 is in the 6309-7049, the others are assumed to be original Seikos.



Hopefully these will all return decent power reserve numbers and then I can use my experience to tackle the issues with the 6139.

 

Hello Jim,

I discovered this very interesting post only now... Good job! Also nice to see the comments from the forum helpful watchmakers.

Cheers,
François