Problem Omega calibre 1120 (ETA 2892)

[Rolexman]

So I fully disassembled, cleaned and oiled an Omega calibre 1120 for a friend (and damn was it dirty).

I put it back together and now the twilight-zone begins. When on the vibrograph the rate is affected by the position of the rotor.... yes, the position of the rotor. And not just a little bit. E.g. when the rotor is on top the movement runs slow and when I turn the rotor only half a turn it runs fast (movement in horizontal position).

I'm out of ideas so I hope an other movement guru can give me some insight on a probable cause?

Thanks in advance!

Mark.

[RWG Technical]

Not sure what you have done so far, so this is what I would do based on your comments.

1. Remove the rotor

2. Check the timing again and note how it reacts

3. Test it Dial Up, Dial Dn, and Crown Down, what are the readings over say 30 seconds time

4. Make sure the gain on the vibrograph is fully maxed out or as high as possible without it skipping, you want the mic to pick up the pallet giving the impulse to the impulse jewel, not the escape locking on the pallet stone

5. Demagnitise the watch, but the hairspring is non-magnetic so it shouldn't really make a difference.

6. Check the hairspring for centering, coils concentric and flat and not touching.

7. Check the regulator pins, watch with a 10X loupe as the hairspring winds and unwinds, is it always touching the pins or does it touch and float free

That should be enough to keep you busy for a few minutes...curious as to the findings...

And if that doesn't help, obviously you have to De-Gauss the Flux Capacitor, that's always a problem on these models.

[Utheman]

And if that doesn't help, obviously you have to De-Gauss the Flux Capacitor, that's always a problem on these models.

... and that's gonna take about 1.21 gigawatts

[Rolexman]

Not sure what you have done so far, so this is what I would do based on your comments.

1. Remove the rotor

2. Check the timing again and note how it reacts

3. Test it Dial Up, Dial Dn, and Crown Down, what are the readings over say 30 seconds time

4. Make sure the gain on the vibrograph is fully maxed out or as high as possible without it skipping, you want the mic to pick up the pallet giving the impulse to the impulse jewel, not the escape locking on the pallet stone

5. Demagnitise the watch, but the hairspring is non-magnetic so it shouldn't really make a difference.

6. Check the hairspring for centering, coils concentric and flat and not touching.

7. Check the regulator pins, watch with a 10X loupe as the hairspring winds and unwinds, is it always touching the pins or does it touch and float free

That should be enough to keep you busy for a few minutes...curious as to the findings...

And if that doesn't help, obviously you have to De-Gauss the Flux Capacitor, that's always a problem on these models.

An answer by a guru it is ....Thanks! Will check it out tonight.

[Rolexman]

Not sure what you have done so far, so this is what I would do based on your comments.

1. Remove the rotor

2. Check the timing again and note how it reacts

3. Test it Dial Up, Dial Dn, and Crown Down, what are the readings over say 30 seconds time

4. Make sure the gain on the vibrograph is fully maxed out or as high as possible without it skipping, you want the mic to pick up the pallet giving the impulse to the impulse jewel, not the escape locking on the pallet stone

5. Demagnitise the watch, but the hairspring is non-magnetic so it shouldn't really make a difference.

6. Check the hairspring for centering, coils concentric and flat and not touching.

7. Check the regulator pins, watch with a 10X loupe as the hairspring winds and unwinds, is it always touching the pins or does it touch and float free

That should be enough to keep you busy for a few minutes...curious as to the findings...

And if that doesn't help, obviously you have to De-Gauss the Flux Capacitor, that's always a problem on these models.

1. done

2. rate more stable

3. beat error verry irregular. 0 dial down and 0.5 crown down

4. no mic configuration possible

5. done, no effect

6. everything perfectly centered

7. no abnormalities

Now that I'm typing I think it also could be a dirty pallet fork jewel... will look at it over the weekend.

Mark.

[RWG Technical]

Ok, great feedback.

On no 3, that should not be happening, also have a good look with 10X loup at balance pivots for damage etc.

Let me know how the rest of it goes...

[Rolexman]

Ok, great feedback.

On no 3, that should not be happening, also have a good look with 10X loup at balance pivots for damage etc.

Let me know how the rest of it goes...

Well Rob,

I think I overlooked #7. It was touching one of the studs all the time. After adjusting the stud so that the hair spring touches and then floats free the beat error improved. One thing I find peculiar is that the rate drops when shifting from dial up to crown down. Normally it gains speed.... also I find the amplitude on the low side for a freshly serviced 2892.

Some ratings:

Dial up

+7 s/d

167 o

0.0 ms

Crown down

-3 s/d

166 o

0.2 ms

[RWG Technical]

Glad you found something.

If the 160 is the amplitude degress, that is way too low and something is wrong, may be best to see if the train wheels are all free and have the correct end shake, it appears as if there is friction somewhere or a loss of power...