Seiko 7A38 - by the numbers

Hi all, 

I've been directed here by the guys over on the MWR forums. I was wondering if you could help me with an issue with my Gen 1 I've recently purchased. The chronograph functions fine - 10ths and the sweep seconds... but the minute register does not advance. Please see the video below:

https://youtu.be/WCY0ynf-dV0

I had to reset the position of the hands when it arrived (crown pos 1, use the pushers to advance) but the minutes does not move when the chrono is moving, nor via this method, or the sweep test by long pushing the 4 o'clock pusher.

I can see it's trying to move. Is there a 'master reset' I can try, or is it a service only deal to get fixed? I've been in contact with the vendor, who's stated it was tested to 10 mins with all hands working as should.

Cheers

Jason.

Jason. There is no 'master reset' - only the inbuilt chronograph self test (by holding the 4 o'clock pusher in for two seconds).

All three chronograph hands, including the 30 minute counter, should complete one revolution and return to their starting points.

You say that it's trying to move - by that I presume you mean it's twitching ? That's an encouraging sign. It may be just suffering from lack of use / old sticky oil and might possibly benefit from a 'kick start'. I recently had the same symptoms with an incoming 7A38.

I'm not saying it will always work, but try withdrawing the crown stem and carefully drop the dial / movement out. Give the 30 minute sub-dial hand a little nudge with the point of a wooden cocktail stick. You should feel some magnetic resistance as the rotor turns. It might only need pushing round one or two divisions. If that does the trick, 'work' it for a while using the inbuilt self test.

Thanks for the advice. I will try this later today. 

Something I forgot to add. Suggest setting the hour and minute hands to 12 o'clock (under the sweep second hand), before dropping the movement out. That way, you'll know where they are, in relation to the back-plate. Less chance for them snagging on anything. The minute dial ring may stay with the case, or come out cleanly with the dial / movement or it may foul on the inside of the watch case and drop down diagonally. Then there's the risk of the hands catching on it. See this photo (as a similar example).

Well, it's a mixture of good news and bad.

The minutes register now works, and moves under the check function. I can also move the minutes hand using the 10'oclock button whilst in setting mode. The minutes hand moves and registers the elapsed minutes - but only when it feels like it. Sometimes it'll manage up to 10 mins, other times it only registers 1 before it sticks again.

I'm guessing that this is indicative of very old sticky oil, and the coil is fine (otherwise I wouldn't be able to set or see the hand one under the check function).

I'm currently watching it recording at the moment - it's just gone past 19 mins... the longest it's gone before sticking. I'm going to keep it running and see what happens.

Jason subsequently followed up with an update in the thread he'd started on MWR, later yesterday afternoon:

http://www.mwrforum.net/forums/showthread.php?79250  Issue with Gen 1 RAF Seiko 7A28