zOwie Omega Discussion Forum

: There are three versions of the calibre 2500 - A, B and C. The A
: version was used only in the first limited and numbered Deville
: Co-axials; your watch does not have one.

: The GMT version is the calibre 2528, of which there are A and B
: versions.
: 2500B is the same calibre as 2528A, which has a GMT module on it.
: 2500C is the same calibre as 2528B.

: The 2500B and 2528A have a known issue with failing to start after
: setting. These calibres beat at 28,800 or 8 ticks per second. I
: have a Deville 2500B, and it sometimes exhibits this issue.
: Rather than having the watch serviced, I simply look at the
: watch after I set it and first put it on to ensure it is
: running. A light tap or shake of the wrist is all that is
: required.

: Omega changed the 2500C and 2528B to beat at 25,600 or 7 beats per
: second, which is closer to the ideal frequency for the coaxial
: escapement (I'm told), making it a better timekeeper, more
: reliable and stable. I have a Deville GMT 2528B and it has no
: issues.

: See these one second exposures to see the difference in my two very
: similar watches.

:
:
: 2528B with 7 beats per second 2500B with 8 beats per second

:
:
: 2528B with 7 beats per second 2500B with 8 beats per second

: Rather than servicing your watch (and any 8 beats per second
: movements), I understand Omega often replaced the movements with
: the more stable 7 beats per second version. Very few people
: notice the difference, and timekeeping usually improves.

: If you are curious, take a one second exposure of your second hand
: and count the beats. One of your photographer friends would
: relish the challenge if you don't have the time and equipment.

: I strongly suspect you have (now) a 7 beats per second watch.

: Other than this issue (where Omega did not follow the advice of the
: inventor of the coaxial escapement, George Daniels, to use 7
: beats per second from the start), I am aware of no other issues.
: As with most new technologies coming to market, there were a few
: missteps along the way.

: Sam aka Hewybaby

I too had problems with my SeMP GMT, cal 2628A (sorry to correct you Sam... :-) ) The first problem was it stopped running and was dealt with under warranty, the problem I suspect on that occasion was the (over)oiling of the escapement, causing fling-off onto the hair-spring. There were also isolated cases I believe, as Sam says, due to the high-ish beat rate causing the pallet fork to jam. The second failure was as the OP described, except mine stuck at ten. The watch could be quickset ok with no problem but when the watch was left to actually run, the hour hand would stick at about 10 pm. It was out of warranty, yet Omega UK fixed it for free, only saying it was a "material failure", suggesting there seems to be a known fault with the newer quickset GMT's and isn't just confined to the co-ax models, I've read of similar hour hand failures on cal.1128's...
By the way, the synthetic lubricants used in modern watches don't have the same propensity to coagulate like the older mineral lubricants but that's not to say you shouldn't have it serviced round about the recommended service intervals...
Oh, and my watch has been fine since... :-)