Need help finding a performance problem on a Seiko 7009 movement

[Ronenash]

Hi all,

I need the help of this wonderful community. I have serviced a 7009 Seiko movement and I have a problem I am having a hard time understanding. Hope someone can steer me in the right direction. After I set the time the watch runs great with high amplitude and 0 beat error as measured on a timegrapher for 20 seconds or so after which the performance starts degrading until eventually the watch stops completely. If I move the hands (as in reset the time) a few turns the movement starts running again with good performance and then degrades again to a complete stop.

I am not sure where to look for the problem. Any help will be greatly appreciated.

Best,

Ronen

[nickelsilver]

How long is "eventually" ? Sounds like something is dragging in the motion work, the gearing that moves the hands. Try pulling the canon pinion and see if the watch still stops.

[watchweasol]

Hi  I would agree with Nicklesilver, remove dial and hands plus canon and re run the tests on the TG, if ok replace parts one by one whilst testing. 

[Ronenash]

Thank you Nicklesilver and watchweasol.

The amplitude and rate go down after coming to a complete stop after 3-4 minutes.

I will try this today and post back the results. 

 

Edited November 10, 2022 by Ronenash

[JohnR725]

5 hours ago, Ronenash said:

After I set the time the watch runs great with high amplitude and 0 beat error as measured on a timegrapher for 20 seconds

always nice to give us the actual numbers like what exactly is a high amplitude especially were discussing a Seiko and nice to give us a picture. Also nice when you're putting it on the timing machine to time more than one position bike may be crowned down it would be nice for instance a minimum of two ideally I like more but will go with two

2 hours ago, Ronenash said:

The amplitude and rate go down after coming to a complete stop after 3-4 minutes.

then this isn't a timing issue. does it do this gradually or is it doesn't do it suddenly? I agree with the others there's definitely a mechanical issue somewhere else it has probably very little to do with the balance wheel if you come to a told.. If you remove the balance wheel and push on the pallet fork is there any power at all there when the watches come to a stop?

[Ronenash]

OK, so I found the source of the problem but cannot figure out the reason. As soon as I install the day finger and tighten the screw the movement starts loose amplitude until it eventually halts. 

Normal amplitude is between 250 and 260 degrees very consistent with the movement in the face up position and as mentioned above, as soon as the day finger is installed it starts to loose amplitude. I will leave it overnight to run with the day finger removed to confirm this for sure. I have also included the schematic for the 7009 maybe someone will get an idea.

Thanks for all the help thus far.

7009A.pdf

[Malocchio]

Are you using a correct screw? The day finger should be loose after the screw is tightened.

[watchweasol]

Hi Malocchio   has pre empted my next question. having "serviced" the watch its a distinct possibility that the wrong screw is installed and is binding the day finger

[JohnR725]

8 hours ago, Ronenash said:

As soon as I install the day finger and tighten the screw t

I see others have beaten me to the answer but I'm going to stated anyway. It's amazing what will happen to a running watch if the wrong screw is in the wrong place. I had a vintage 18 size full plate American pocket watch which means limited visibility. One of the screws on the dial side was in the wrong place and hit the spoke of the third wheel. So yes it's amazing of the screws sticks too far down and touches something it shouldn't the watch will come to a stop if you're lucky. Worst-case but I'm the skip over how I know this one the wrong screw you could end up breaking something. But seeing as how your watch runs with the screw out you haven't broken anything you just need to evaluate whether you have the right screw or not.

[Ronenash]

Thank you all for the super valuable help. I have finally figured it out this morning. There was a microscopic string of fiber between the wheel and the finger which cause friction when the screw was tightened. 

I have now completed my first full service for a Seiko 5 gifted to me by my father when I graduated high school. Brought new life to this almost 40 years old watch. I am super happy for being able to complete this project.

 

Now to my next project, a Hamilton 992b.

Ronen

[watchweasol]

Brilliant always good to hear a success story, onward and upward.