The strangest a7750 issue Ive ever seen?

[Guest carlsbadrolex]

Ok, I have an a7750 with a rather odd issue. When the chrono is started the center second takes off smoothly. When the center second reaches 12 the minute counter jumps to the 1 minute marker. When the center second reaches the 3 ocklock position (15 seconds later), the minute hand jumps to the 2 minute marker.

When the center second hand moves to the 12 oclock position again, the minute hand will move to the 3 minute marker for a moment, and then jump backwards to the 2 minute marker. (effectively putting it where it should be)

What mechanism (besides the return button) allows the gear to move in reverse (but only one click)? Ive had ALOT of Swiss and Asian 7750's and never seen this one before.

[FxrAndy]

I had a similar problem with a seagul, st 18 after i had dislodged the spring that keeps the minute totaliser gear in position, but mine would not count nore than 3 min and then just flick between 2 and 3,

[Guest carlsbadrolex]

DING DING DING... That is exactly what is happening. I had not let it run more than three minutes before posting this.

It will not go past 3 minutes, and after resetting it about 10 times, it would only advance at all a couple times. Most of the time, it doesnt even move to the first minute marker.

How difficult of a fix is this? Is this an open the back and see the problem or is the issue on the front of the movement?

THANK YOU...

Im going to try to do a quick video later, its kinda funny to watch actually.

[FxrAndy]

on the st18 it was easy to see, at the side of the totaliser gear is a hair thin long straght spring witha v bend at the end, this sits in the teeth of the totaliser gear and alows it to move on one min at a time , you should be able to see it from the back.

[FxrAndy]

have a look at the picture below,

[Guest carlsbadrolex]

Andy, Your the Man!!! Sure enough, that little spring had popped up and over the minute totalizer gear. Put it back in place and its working like a charm!

Thanks RWG and Andy for another brilliant piece of information!

(I still dont see how this gear being out of place allowed the gear to roll backwards) But its fixed and THATS whats important!

T

[FxrAndy]

Glad i could be of help.