Hands keep going out of sync on a Seiko Bellmatic

[quantieme]

Hi All, I have just serviced two Seiko Bellmatics, one is fine but the other one has developed this fault whereby the hands keep going out of sync with the date change. the first time it happened i thought it was my error as after 2 days the date wasnt changing until 9:30 AM so i reset the hands to 12 and again after a couple of days it did the same thing but wasnt changing until 7:30 AM, I reset the hands again and sure enough it is now out of sync again and not changing until 1:30 AM. The hands are not loose as it keeps spot on time, I have checked for anything sticking and manually followed the date change on the crown which is all fine, the quickset day change on the alarm button is fine as is the date change manually on the crown. I have even taken the working one apart and compared them but can see nothing wrong. This has got me stumped any advice would be appreciated. I have uploaded a pic of the faulty movement incase anyone can see anything. Thanks in advance. Tony

 

[Kalanag]

The only reason I can imagine for hours and calendar getting out of sync is a faulty meshing of gears between hour wheel and date wheel (a bit complicated with this caliber).

 

Edited July 27, 2022 by Kalanag

[Nucejoe]

 I'd be surprised if the good one doesn't start  misbehaving soon. Out of sync complications is the hallmark of Seiko.

I would set the date to change couple of hrs before the 24th hr and hope for the best.

Down in my neck of the woods we call Seiko imprecise gears  "diesel  massey ferguson". 

 

 

[jdm]

2 minutes ago, Nucejoe said:

 I'd be surprised if the good one doesn't start  misbehaving soon. 

Your post is assuming, opinioned and of no help. If anyone will find it amusing, at least will have served a purpose. 

[Nucejoe]

30 minutes ago, jdm said:

Your post is assuming, opinioned and of no help. If anyone will find it amusing, at least will have served a purpose. 

But I have been helpful, a trick to reduce the out of sync error. 

The error is not accumulative here?   is it?     

Regds

 

 

 

[quantieme]

5 hours ago, Kalanag said:

The only reason I can imagine for hours and calendar getting out of sync is a faulty meshing of gears between hour wheel and date wheel (a bit complicated with this caliber).

 

thanks, i have reset it again but not cased it, if it goes out again i will check that as it would make sense.

4 hours ago, Nucejoe said:

But I have been helpful, a trick to reduce the out of sync error. 

The error is not accumulative here?   is it?     

Regds

 

 

 

thanks i will keep that option on the reserve list lol.