I’ve heard the movement has a tendency to require frequent service of its automatic winding mechanism. Not sure if there’s any validity to this though.
That's interesting... I don't have any personal experience with this movement, but it seems very similar to the omega 55X series, with a number of changes. The latter doesn't have many issues with the automatic winding, so I would think that the 431 series would be similar considering the automatic winding mechanism is very, very similar.
To answer OP, yes. I do have another question regarding ultra-chron movement in general. I realize that all 17-jewel 431 (please correct me) are adjusted to 3 positions, and all 25-jewel 431 (again please correct me) are adjusted to 4 pos. and temp. But however only limited ultra-chron bear the "Chronometer" designation on the dial, meaning only those that sent in for chronometer test had the inscription. My point is, I have always read that "all ultra-chron are chronometer grade hence the "chron" in the name"... which I find un-supportive. I understand that it's a adjusted movement, but without the chronometer designation on dial and on the rotor, it's hard for me to swallow that all ultra-chron are chronometer tested.
Other than the special gold (colored, not solid) trimmed rotor, I am unaware of any differences in parts between the rated and unrated versions of the cal. 431 movements. However, I’m sure there was extra labor involved in making the adjustments to ensure the movement met COSC standards. gatorcpa
Thanks; There is also the "Chonometer" wording inscribed on the rotor other than the gold trim for the rated ones. But my questions is really if all ultra-chron are chronometer tested. I don't believe so even with the adjustment inscription on the movement saying it's adjusted to 3 pos. and etc. I believe if there is no chronometer on dial, it was not chronometer tested.
Appteciate the responses. So my ultra chron auto winds and runs well, but when I try to wind by hand, the crown will not budge. Service time?
Correct! Yes. I believe that the mainsprings and barrels on these are sealed units that are not supposed to be opened and lubricated. Once the oil inside dries up, the whole thing has to be replaced. gatorcpa
Yes. This is not related to the barrel or mainspring though, considering the watch still winds using the automatic winding. Could be winding/setting issues, or locking up of the "reversing wheel" in the automatic winding. I've not found the automatic winding on these to be particularly problematic, but of course worn parts need to be replaced and the service done correctly. Of course being a 36,000 A/hr movement, service frequency will tend to be more often on these. These do use a "sealed" mainspring barrel... Many companies used these in this same time frame...Bulova, Longines, Zodiac...some are more conducive to opening and replacing the barrel than others. For example on most Bulovas, it's not a problem at all and I;'ve done it often. On Zodiacs, the way the barrel lid is fastened makes opening it without damage quite difficult. For the Longines in question, I have always been able to find NOS barrel complete, so I've not opened them. However the barrel lids are not crimped like they are on the Zodiacs. Cheers, Al
I'm not sure if all UCs have this, but my 431 seems to have a similar issue: it's difficult to wind manually, owing among others to the small crown compared to the earlier 290/340 series. I do notice however that it's comparatively easy when the power reserve is low.
@Archer These sealed barrels seem to be rather difficult to obtain. May I ask if there is a particular time when these need to be replaced, and where one without a thick suppliers' Rolodex could get these?
I just ask the watch material suppliers I use...no idea where you are located but there are plenty of suppliers out there. Jules Borel in the US (and many others) Cousins in the UK, Ernst Westphal in Germany, etc. You could also look on eBay I suppose... I always replace the mainsprings in watches at service, so if I'm servicing one of these, I would be putting a new sealed barrel in. Cheers, Al
I remember someone saying that if there is no pic, then the conversation never took place So here it goes. This is the watch in question.