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Why the CHS GMT movements are failing

Dr Fun Socks

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I know im not the only one but my two chs movements that failed have been running spot on since the day kj sent them back. The guy is a wizard of a watch maker and i am eternally grateful for his help :) Also, independent setting gmt hand is a pointless function for the amount you will use it. Quick change date for the win (even though i keep them both on winders).
 
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Timerajput

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Hi all I have an explorer 2 from china and the time wont go past 9pm and its a smooth transition when changing the hours rather than the jumpy one is there anyone I can it to? Thanks
 

jpchub

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KJ2020 an ex colleague of mine has the ZF Tudor GMT that I helped with ordering while
I was buying a watch. The movement now failed. It has the hour hand that is stuck. Can you perhaps point me in the right direction as to where I can get the custom made IDW support you mention in post #199?
 

jpchub

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KJ2020 an ex colleague of mine has the ZF Tudor GMT that I helped with ordering while
I was buying a watch. The movement now failed. It has the hour hand that is stuck. Can you perhaps point me in the right direction as to where I can get the custom made IDW support you mention in post #199?
 

KJ2020

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KJ2020 an ex colleague of mine has the ZF Tudor GMT that I helped with ordering while
I was buying a watch. The movement now failed. It has the hour hand that is stuck. Can you perhaps point me in the right direction as to where I can get the custom made IDW support you mention in post #199?

Those movements are 2836 ICHS bro so it wouldn't be the same repair it needs. Any rep watchmaker should be able to address it. A whole new movement is easliy found if needed.

ST-2146
https://bosshua007.myshopify.com/collections/movememt-parts
 

jpchub

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KJ2020 oh dear, how’s my reading?! Thanx a mil, those are nice and cheap as well, so probably best route. Still going to open it up and see if I can help him out without buying a movement.
 
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rich513

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Absolutely amazing exercise, knowledge and help Tickleshoes. You rock. I have an e-mail out to Li at JTime to get his perspective on the issue and this Explorer II which he stood me is produced by the GMF factory:

 
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beneton

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Hey gang. I finally had a chance to dig into a CHS GMT Master II with a "broken" jumping hour hand. Thought I'd share what I found since I've hand several members reach out with issues.

So props to the rep factories for trying to engineer a solution to get the hand stack correct. Unfortunately, it fails in execution. In short, the parts are so thin and frail that I imagine this will continue happening until it's fixed.

The Jumping Hour is made up of 2 gears which sandwich a spring. Here is a gen 3185/86 version from my watch:

1b34c39de2de93ed7423abe6bca3899e.jpg

7bef09fe673d26d77ea4352d035a47f3.jpg


A strong, thick spring holds those massive fingers against the grooves. Now compared to the Asian solution:

c783c89b1c4199a810d361cc84c5eff4.jpg


And with the top on:
55de943330073eb2ebbdfbbbcde54046.jpg


The spring has to be strong enough to move the top and bottom gears together when the watch is running but have enough give to let them jump independently when adjusting the hour hand. Unfortunately that spring is not up to the task.

As these are custom pieces there are no replacement parts. The only things that can be done are to A.) just live with whatever state the watch is in when broken or B.) glue the top and bottom gears together and reset the hands. This will insure that they don't become out of sync but you will not be able to adjust the hour/GMT hand independently.

Sorry for the bad news guys. Maybe the factory will engineer a better solution but I'd either never adjust the jumping hours or steer clear!

-TickleShoes
I have serviced a watch described as "GMT-Master II 116710 LN VRF Best Edition SA3186 CHS V2". The problem was that the hour hand would not always move easily back and forth, at the crown it felt like a break. The jumping hour wheel collet which should keep the round jewel tight on top of the claws was not sitting on its recess. I had to tighten the collet a bit and snap it back into its place.

Thank you for sharing!