Rotary randomly stops, restart hands set

[Mrfixit 5]

Hello people, I have aquired a 1970 Rotary ladies watch 17 jewel : can run all day or just 20 mins without stopping. Setting the hands restarts. My skill is limited to working on an fhf70 so due to the tiny movement want to approach the likely causes first without wheels out. I am thinking towards the motion side putting resistence on the train ? Thoughts please to point me in the right direction.

Regards all.

[oldhippy 1,891]

It sounds to me like dirt. Just a tiny foreign object will cause this. The best way is to clean the movement, that means taking the whole thing apart. You could try this if you like, that would be let the mainspring down. Remove the complete balance and pallets and then add a little power this just might spin out the foreign object. Before you attempt this just make sure all pivots are oiled, you don't want the wheels spinning in a dry hole, it could shear a pivot off.   

[Mrfixit 5]

36 minutes ago, oldhippy said:

It sounds to me like dirt. Just a tiny foreign object will cause this. The best way is to clean the movement, that means taking the whole thing apart. You could try this if you like, that would be let the mainspring down. Remove the complete balance and pallets and then add a little power this just might spin out the foreign object. Before you attempt this just make sure all pivots are oiled, you don't want the wheels spinning in a dry hole, it could shear a pivot off.   

Excellent, thank you for the advice. Although I've worked on the train on other movements hesitant here due to size and lining up pinions. Will try your suggestion with the balance.

Thank you.

[watchweasol 315]

Hi   Once again Old Hippy is on the ball as my own diagnosis would be exactly as quoted follow that and all will be well, Small movements are delicate and therefore take your time. The smallest I worked on was a ball watch the size of a marble with a broken staff, replaced with a Balance comp, cleaning and reassembling took a while . Take your time and enjoy.

[Chopin 167]

Indeed it sounds like it needs a good service. I hate working on ladies movements but I have to do it every now and then...

[Mrfixit 5]

Thank you commenters for your time and opinions. It's this kind of feedback that gives folk such as myself the confidence to move further within the movements.

Kindest regards to all.

[Ajohnw 3]

I was just curious about faults so googled the movement and found this

https://wahawatches.com/restoration-zentra-watch-with-fhf70-movement/

15 jewels though

John

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[Mrfixit 5]

7 minutes ago, Ajohnw said:

I was just curious about faults so googled the movement and found this

https://wahawatches.com/restoration-zentra-watch-with-fhf70-movement/

15 jewels though

John

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Thanks John. I referred to the FHF70 as the only movement I had fully stripped, whereas this is a rotary movement I believe based on ETA 2412. Good article on the FHF70.

Regards

Chris

[Mrfixit 5]

Update - resolved.

After taking OldHippy's advice and removing the balance and pallet fork gave it a few turns - gears spun up but were reluctant to restart without encouragement. On closer inspection, there was a tiny strand of fabric wrapped around the escape wheel centre shaft. You can only imagine me elation when I grabbed the strand with tweezers and the gears spun into life.

One happy chap.

[anilv 690]

Older ladies watches are not the easiest to work on. I don't like to work on them and when I do its usually a favor for someones heirloom.

The pivots are really fine and the mainsprings are really weak (by design) so if the mainspring gets 'set' and doesn't provide much power the watch wont run well.

My action plan is usually remove power from the spring and remove/check/clean mainspring and the barrel. Next remove/check/clean the balance jewels (Assuming Incabloc or similar) and just dunk the whole thing in the cleaning solution. Dry off properly and use a puffer to get any bits off. You might need to remove some of the keyless parts to access the jewels for oiling. put it together. If it works then good. If it doesn't then that's it.. too bad.

If there is any trace of moisture don't even bother. Even a smidgen of rust on the pivots is enough to make it run poorly. And most ladies watches of the 50-60s had abysmal water protection.

Anilv

 

[oldhippy 1,891]

13 hours ago, Mrfixit said:

Update - resolved.

After taking OldHippy's advice and removing the balance and pallet fork gave it a few turns - gears spun up but were reluctant to restart without encouragement. On closer inspection, there was a tiny strand of fabric wrapped around the escape wheel centre shaft. You can only imagine me elation when I grabbed the strand with tweezers and the gears spun into life.

One happy chap.

Foreign object found and removed.