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HOW TO: Set the time on the GMT II (CHS) A3186 movement

Watch-Out

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1/2/20
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I have replica 116710BLNR with 3186 movement. I was informed by the seller, that it was the top of the line product with exact replica movement. However I have noticed that when changing the date with the jump hour hand, on moving the hour hand back, the date does not move back to the previous day.
Is this normal for a replica 3186 movement

Please read my questions and the answers I have been given... Best way is to not play with the jumping hour hand. Especially not backwards. Best way is to change date in time setting mode. It takes a long time but lowest risk to damage sth.
 

KJ2020

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Hey guys,

Saw this listing - https://puretimewatch.io/gmt-master...-1-best-edition-on-ss-bracelet-sa3186-v2.html

Movement is advertised as A2836, so the "safe bet" movement. However, the title says the movement is a SA3186 V2.
Bit of a newbie here, is this a timebomb?
if so, is it not worth the purchase despite the significantly better price compared to alternatives?

I know you already have your answer from another thread, reposting it here for the benefit of others.

The web description is wrong, although the 2824 CHS timebomb is often mischaracterized as having a 2836.

In GMT Movements Explained, I explained how to identify what you see in the ad pics.

1. The hour hand is on the bottom of the handstack, so it is CHS.

2. The movement is an ETA clone.

There is only one correct conclusion that can be made from those two facts. It is a 2824 CHS timebomb movement.
 

James2020

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Deleted. Reposted in the more relevant thread.
 
Last edited:

Max Dad

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I just purchased the Noob factory GMT II from a TD on this site. Setting the watch is a little complicated due to the custom A3186 / A3187 movement in the watch, so I thought I'd share my findings in a tutorial to help other members.


CROWN POSITIONS:

Position 0 = Crown screwed in
?
Position 1 = crown unscrewed.
?
Position 2 = hour hand adjust, resulting in the date changing when cycled 24 hours.
?
Position 3 (crown full out) = time adjust, including minute hand, hour hand, and GMT hand.

RULES / NOTES:
It seems the main rules to be aware of, are:
- Never adjust the hour/date hand in position 2, whilst GMT hand is between 10:00 - 02:20. This will break the movement apparently.
- Apparently never adjust any of the hands using a clockwise direction on the crown if possible (I found this impractical when setting the minute hand, and mine has not broken).
- I also noticed that moving my crown anti-clockwise changes the the time forwards, which seems to be the opposite to the gen, in which it would adjust the time forwards. So in short, the crown movement seems to adjust things backwards... A little bit strange, but none the less, something to be aware of.

SET THE WATCH IN 4 STEPS:
1. First, set the GMT hand to your time zone, to the nearest hour thats just passed.
2. Second, adjust the minute/hour hand to the actual time.
3. Third, adjust the hour hand.
4. Finally set the date.

STEP 1 - Set the GMT Hand

Always set the GMT hand to the hour that has just passed in your time zone. For example, if it's 05:15, then you would start out by calibrating it to 05:00. If it's 16:38, then you would set it for 16:00.
- First fully pull out the crown to position 3.
- Then adjust the crown anti-clockwise until the GMT hand is pointing to the correct hour on the bezel appropriate to where ever you are. Assuming the actual time is something like 16:38, then move the crown anti-clockwise until the GMT hand is pointing at the number 16 on the bezel or 08:00 on the dial, and the minute hand will be at 00:00 position (ignoring the hour hand for now).
- Push the crown back in to position 1.
- Done. The GMT hand is now set to your time zone.

STEP 2 - Set the minute hand
If you followed the instructions above, as per the example, you will need to wind the minute hand forwards now to the correct minute.
- First pull the crown all the way back out to position 3.
- Then move the crown anti-clockwise to the correct minute. In the example above, you would need to move it forward to 38 minutes (the GMT hand should also move forward slightly to co-ordinate).
- Push the crown back to position 1, and you're done.

STEP 3 - Set the hour hand
By now your GMT hand will be in the right place, and your minute hand will be correct too, so you just need to set the hour hand.
- First pull the crown all the way back out to position 3, then gently push it in with a very small click so it's at position 2.
- Then move the crown anti-clockwise until the hour hand is correct. In the example above this would be at 04 (for 16:38).
- Push the crown back in to position 1, and you're done.

STEP 4 - Set the date
By now your GMT, hour and minute hands will be in the right place, so now you just need to set the date right.
- First pull the crown all the way back out to position 3, then gently push it in a small click so it's at position 2.
- Then move the crown anti-clockwise in 24 hour cycles in order to increment the date forwards.
- Once the date is correct, make sure to keep turning the crown until the hour hand is back on the correct hour.
- Push the crown back in to position 1, and you're done.

Finally, screw the crown back in to position 0

For a better video explanation of how to set the (gen) GMT II, and to understand how to use it in different time zones, I found this video useful:


To understand the crown positions, I found this video useful:


Hope thats helpful.

Is this still valid like with todays versions of this model/movement? If so, when you say GMT between 10 and 2 do you mean 22 and 2 or 10 (like 5) and 2 (1)?? Thx
 

KJ2020

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Is this still valid like with todays versions of this model/movement? If so, when you say GMT between 10 and 2 do you mean 22 and 2 or 10 (like 5) and 2 (1)?? Thx

It is valid only for the 2824 CHS timebomb and the (way more rare) 2813 CHS timebomb movements.

TDs and factories don't call these movements timebombs so you have to know what you are buying.

GMT Movements Explained

Mods for the GMT timebomb

The cautions for "10 to 2" refer to the normal hour hand, when it is displaying PM-to-AM times.The reason for the caution is that during these hours, the calendar driving wheel spring is being put under increasing tension and the operation of the calendar parts puts extra stress on the jump click. This is similar to the same caution about not attempting to quickset change the date on any watch during these hours. It can adversely affect the calendar parts.

The caution has nothing at all to do with the GMT hand or the GMT 24 hour scale on the bezel. It's possible for the GMT hand to be located similarly in this caution zone but it can be operated independently so it should not be used as the determining factor.
 
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Lew

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3/7/21
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Noticed the new Clean Factory GMT Master II uses 'VR3186' is that another name for the A3186?

Really don't want to buy a timebomb, all these rules are far too much for me! Need a movement that won't break if I twist the dial the wrong way or change the time at the wrong time of day
 

KJ2020

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If you have a 2824 CHS timebomb movement, follow these few simple common sense rules to give your jump click a good chance of survival.

Never hour jump backwards through a date change.

Never hour jump backwards more than necessary, for example you can set a seasonal semi‐permanent GMT offset.

Avoid hour jumping forward through a date change as much as possible. If you need to advance through a lot of dates, hour jump from 3AM to 9PM, then use normal time setting from 9PM to 3AM to change the date. Repeat for each date change needed.

Keep the watch on a winder to minimize the need to change dates very often.

Always be gentle and slow with hour jumping. The click is very fragile and additional pressure is put on it when it is forced to drive the calendar parts through a date change.

Fix for the GMT timebomb movement

You can always just not use hour jumping at all, but if you are careful it can last a good while.
 

KJ2020

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Noticed the new Clean Factory GMT Master II uses 'VR3186' is that another name for the A3186?

Really don't want to buy a timebomb, all these rules are far too much for me! Need a movement that won't break if I twist the dial the wrong way or change the time at the wrong time of day

The CF GMT movement is not a timebomb bro.
 
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Lew

You're Saying I Can Sell?
3/7/21
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The CF GMT movement is not a timebomb bro.

Thanks realised that now!

Mine should be arriving soon, is there anything I need to be aware of with this movement? Never had a watch with a special movement like this before, does it matter if I accidentally turn back time? Can I change the date whenever I need to?
 

KJ2020

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Thanks realised that now!

Mine should be arriving soon, is there anything I need to be aware of with this movement? Never had a watch with a special movement like this before, does it matter if I accidentally turn back time? Can I change the date whenever I need to?

I have a gen 3185 and do not change the date backwards on it, even though you can on both the gen and the rep VR3185/6. You have to go back to about 9PM for the date is change backwards.

There are no other extra precautions using those rep movements. If you want detailed info on them, you can just use the Rolex user guide. As with any mechanical date watch, you should not quickset change the date when the local time on the watch is between 10PM and 2AM.

https://www.rolex.com/media/user-guides.html
 
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