Hamilton

[Melus28]

I have been having trouble getting this watch to run properly.

The problem is that the balance wheel moves freely, The staff, roller jewel, and hairspring all seem to be fine. The balance wheel seems to be 'centered and not touching the watch. The fork has power and seems to be 'poised' correctly, but I suspect this may be where the problem lies. The balance goes back and forth a few times, and just before it sets itself into a proper rhythm, the balance seems to get 'stuck' at about the bottom of the swing to the left. About '7' o'clock.

The model 987S has no poising screws, just a 'split' at both ends of the pallet to open or close.

Any suggestions as to my next step?

kind regards

Melus

[Jtrenalone]

Hello Melus,
If there is no apparent cause for the balance to stop, the first thing I would do is remove the pallet fork, and hairspring and install the balance alone. Then see if it spins freely in all positions. If so, re-introduce the hairspring, and check again.

By doing this, you can better isolate the problem,
Hope that helps,
Joel

[Don Dahlberg]

I would follow Joel's advise, but before putting the hairspring back return the pallet and run the watch without a hairspring. This is called "half-timing". A watch should run for several seconds without a harispring. If not, something is binding or you are losing energy somewhere.

Don