Rolex 3130 Amplitude

[JustBlueFish]

I have a brand new Rolex OP with the 3130 movement. On my No. 1000 timegrapher I'm seeing something strange with regards to amplitude. This is being tested on a watch at full wind, with lift angle settings of 52 deg in the flat dial up position.

When I take the watch off wrist and place it on the timegrapher, I always start out with an amplitude in the 290 range. As it rests on the TG stand for a few minutes the amplitude will slowly drop and eventually settle around 270. It will fluctuate up and down a few degrees. I've seen it go as low as 267 and it will go up to 273. I've monitored it for the better part of an hour and it seems pretty consistent.

I've tried this several times and I always seem to get the same results. Higher amplitude at first and once it rests for a couple minutes it drops down. 

#1 I'm concerned with how it seems to drop amplitude.

#2 Isn't 270 for a brand new Rolex 3130 in the dial up position at full wind on the bad side, or am I wrong?

#3 My AD says "it's in spec". Should I be happy with this?

Thank you for the information.

[JustBlueFish]

Here’s a shot of my timegrapher when the amplitude was at its lowest. Everything else looks fine.





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[clockboy]

Not a lot wrong I would say. Over a long period the amplitude will drop slightly because the auto wind is not working and so it is effective unwinding. An amplitude of 270 is not bad and for some watches such as Seiko's it is impossible to achieve. If you are still worried then have it serviced by Rolex. 

[rodabod]

1. You need to understand how a timegrapher works in order to interpret (mis)readings. Basically, it’s unlikely you have a problem with the amplitude changing.

2. You need to achieve 270 degrees to achieve “good” isochronism with respect to balance poise. For that reason, it’s considered a target.  How does it measure dial-down? And are you sure the mainspring bridle had started to slip (fully wound) before you measured?

3. I personally wouldn’t trust anything a dealer says, but I’m not saying they are either right or wrong. I think there is a slight danger of misunderstanding when non-watchmakers use timegraphers to make judgements on watch movements. I believe this is the main reason why we see people posting online about getting beat-error as close to zero as possible, when in reality it doesn’t matter much as long as it’s reasonably low for the given beat-rate. 

[Delgetti]

I have the spec here lying in front of me (won't post a pic for copyright reasons). About amplitude for 3130 it claims 2 criterias:

- after maximum winding: in dial up and dial down position amp must be smaller than 310

- after maximum winding followed by 24 hours unwinding: in crown down, crown left and crown up position amp must be higher than 200

There is no further comment how high the full winding amp should be