A customer has sent in his lovely Grand Seiko Chronometer for a service. It’s running and looks good, but could do with a routine service.
Great looking movement with a tadpole regulator.
Watch is preforming okay, but under the microscope I can see a lot of gunk.
Dial is in beautiful condition.
Hands and dial removed you can see the typically complicated Seiko wind/setting and date mechanism.
The date disk slides on jewels that are set in the base plate.
Here you can see the gear train layout and the hacking lever.
Here you can see the gunk I was talking about. It will not damage the movement, but if it gets to the dial or date wheel it will cause damage.
The lid of the barrel is jewelled.
Movement has been cleaned and ready to be put back together.
I see that the balance moves freely after fitting the shock jewels.
I fit the centre wheel.
The clean mainspring goes back into the barrel.
Movement almost back together.
Winding/setting mechanism and the date mechanism back in place.
Movement starts running straight away after fitting the balance.
No worries here!
Dial and hands go back onto the movement.
Movement back in the case looking grand!
A very nice Seiko!
2 Responses to Service: Grand Seiko 9990 calibre 5722A
Very nice! Startlingly similar to 5740C Don’t you think M 😉
One thing they definitely have in common is the overall good build quality.