Low Amplitude After 30 Mins

[DJT2]

Hi guys, I've just cleaned & serviced a eta 2832. if I wind it fully I get good results on the timegraph however after about 30min on the timegraph the amplitude is low approx 160 & it's losing 118 s/d (sorry no image as I'm away from home) any ideas?

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[DJT2]

Also this happens once I installed the automatic winder mechanism

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[rogart63]

Hi guys, I've just cleaned & serviced a eta 2832. if I wind it fully I get good results on the timegraph however after about 30min on the timegraph the amplitude is low approx 160 & it's losing 118 s/d (sorry no image as I'm away from home) any ideas?

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Not super high amplitud from the beginning ?. Maybe needs a new mainspring ? 

[DJT2]

Not super high amplitud from the beginning ?. Maybe needs a new mainspring ?

Thanks, what sort of reading should I expect?

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[Marc]

+1 rogart63.

I would be inclined to look at main spring as my first port of call too.

 

Your photo of the disassembled parts shows the main spring barrel intact which maybe suggests that you didn't clean, inspect, and then re-lubricate the main spring.

It is actually quite important to have the main spring out during a service so that you can check condition of the spring, and the side and end shake of the arbor in the barrel, all of which could sap power. If I'm working on a watch that has known power issues then I will also measure the main spring thickness and length and compare against what is supposed to be in there in case someone has put an incorrect spring in in the past.

 

If all is well with the main spring and the train is running nice and free then I would be looking to see an amplitude of >270 at full wind with a re-used spring, and preferably nearer to 300+ with a new spring.

[DJT2]

+1 rogart63.

I would be inclined to look at main spring as my first port of call too.

Your photo of the disassembled parts shows the main spring barrel intact which maybe suggests that you didn't clean, inspect, and then re-lubricate the main spring.

It is actually quite important to have the main spring out during a service so that you can check condition of the spring, and the side and end shake of the arbor in the barrel, all of which could sap power. If I'm working on a watch that has known power issues then I will also measure the main spring thickness and length and compare against what is supposed to be in there in case someone has put an incorrect spring in in the past.

If all is well with the main spring and the train is running nice and free then I would be looking to see an amplitude of >270 at full wind with a re-used spring, and preferably nearer to 300+ with a new spring.

Good eyes Marc. You are infact correct, I didn't disassemble the mainspring as I don't have a mainspring winder. I'll order a new one tonight.

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[DJT2]

Another quick question if I may. On disassembly I noticed there was no balance stop. I thought this strange as looking at the specifications on rantf it states that the 2832 has hack. I tried the balance stop off a 2836 & it fit the plate but the end did not reach the balance wheel. Would this mean it's the wrong size wheel?

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[rogart63]

No i doesn't ? The different sized balance wheel is because there is a difference in the frequency . 36000 to 28800 for 2836 . If you toke the balance from a 2836 you are in trouble ? 

[Marc]

I would be surprised if it wasn't the correct balance if it is timing ok, more likely a different hack lever for the 2836 but I'm not overly familiar with the 2832.

 

Thinking out loud here, the 2832 runs at 36000bph according to Ranfft. I believe that the 2836 is a 28800 ticker. I'm thinking that it is probably necessary to make the balance wheel smaller and lighter to reduce it's inertia to obtain the increase in rate. If that is the case then (assuming the hack lever bears on the balance to stop it) the 2832 will need a longer hack lever to reach the rim of the balance if the rest of the movement architecture stays the same. Just a thought.

 

When you open the barrel to take the old spring out make a note of how the spring is oriented ( clockwise or anticlockwise) before you remove it, just saves a bit of time later. Also, why not have a couple of practice runs winding the old spring back in by hand before you install the new, it's a useful capability to have until you find you have to fork out for a winder.

 

Also check the shakes on the barrel arbor and don't forget your braking grease on the barrel wall.

 

Have fun. :thumbsu:

[Marc]

You beat me to it rogart :D

[DJT2]

Thanks guys. Just found this information.

All hand fitting and dimensions are the same between the 28,800 and 36,000 bph versions. Further, all parts, except the second wheel (#227), escape wheel (#705), balance assembly (# 721) and hack lever (#9433) are common between the 28,800 and 36,000 bph versions. (Even the mainsprings, a fact borne out by the Bestfit catalog.)

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[JohnR725]

Also this happens once I installed the automatic winder mechanism

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What happens if you do not install the automatic winding mechanism?

 

Then as this is a 36,000 bph it may very likely not have the amplitude of a lower frequency watch. 

 

So the normal watch when you wind it up super tight to get that extra bit of power and you see it running like this then dropping dramatically is because you don't have enough power to run the watch. So the mainspring would be number one place to check. But as this is a high-frequency watch running twice as fast as normal watch everything becomes much more critical like lubrication. Conceivably this watch will wear out twice as fast as a watch running at 18,000 bph.

 

Then the link below has some information on high-frequency watches

 

http://www.watchfreeks.com/33-general-watch-discussions/12946-36-000-bph-movements.html

[DJT2]

What happens if you do not install the automatic winding mechanism?

Then as this is a 36,000 bph it may very likely not have the amplitude of a lower frequency watch.

So the normal watch when you wind it up super tight to get that extra bit of power and you see it running like this then dropping dramatically is because you don't have enough power to run the watch. So the mainspring would be number one place to check. But as this is a high-frequency watch running twice as fast as normal watch everything becomes much more critical like lubrication. Conceivably this watch will wear out twice as fast as a watch running at 18,000 bph.

Then the link below has some information on high-frequency watches

http://www.watchfreeks.com/33-general-watch-discussions/12946-36-000-bph-movements.html

Nice read & very informative. Without the automatic mech it seems to stay regulated & retain higher amplitude much longer. See image however as soon as I fit the automatic winding mechanism, within mins the amplitude falls & starts losing fluctuating between -50 s/d & as much as -130 s/d totally unstable.

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[Geo]

I find it strange that the issue manifests as soon as the auto mechanism is fitted. Is there a possibility that you have mixed up a couple of the screws and that a longer screw is pressing on a bridge or wheel and causing the immediate drop in amplitudes?

[DJT2]

I find it strange that the issue manifests as soon as the auto mechanism is fitted. Is there a possibility that you have mixed up a couple of the screws and that a longer screw is pressing on a bridge or wheel and causing the immediate drop in amplitudes?

Hi Geo, I don't think so. I'm using the only 2 blue screws left to attach the auto mech.

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[Geo]

It was just a thought because of the immediate change.

Here's another thought. It might be an idea to check end shake on the pinions just I case there is a tight one and fitting the auto bridge makes it even tighter.

[DJT2]

It was just a thought because of the immediate change.

Here's another thought. It might be an idea to check end shake on the pinions just I case there is a tight one and fitting the auto bridge makes it even tighter.

I'll have a look at that as well as the mainspring. I'm away now in my truck until Fri, but I'll report back with my findings on Friday nite. Thanks guys

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[rogart63]

You beat me to it rogart :D

You explained it far better then i ever could :). 

Edited July 20, 2015 by rogart63

[DJT2]

You explained it far better then i ever could :).

Thanks buddy. Just ordered a new mainspring, but as suggested earlier I'll disassemble the old mainspring & have a go at handwinding for fun.

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[frenchie]

Lots of good suggestions here.

A few of mine (not sure they all make sense, I'm still learning :p)

 

Does the auto mechanism turn freely in both directions outside the movement (maybe a bad bearing) ?

 

Does it engage properly when you add it to the movement ?

 

Does it wind the mainspring without catching or skipping ?

[DJT2]

Lots of good suggestions here.

A few of mine (not sure they all make sense, I'm still learning [emoji14])

Does the auto mechanism turn freely in both directions outside the movement (maybe a bad bearing) ?

Does it engage properly when you add it to the movement ?

Does it wind the mainspring without catching or skipping ?

Hi Frenchie, Thanks for your thoughts, The answer is yes, yes & yes. I've ordered a new mainspring & the correct stop lever. I do believe it's the mainspring, as after full wind the watch stopped after only 8hrs.

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