Low amplitude in vertical position

[matabog]

Hello! 

I cleaned a wostok 2209 and I have the following problem: in vertical position (CD) the amplitude decreases from 280 to 190 and it looses (-60s).Dial up it has about 280 deg and it is in +-10s. I tinkered a bit with the HS and it is as flat and centered as I can. It is a Breguet HS.

 

Any ideas?

Thank you!

Bogdan

[Gasman]

The amplitude always decreases in vertical positions compared to Dial up and down. however 90 degrees of loss is excessive.  The amplitude reduction may account for the rate reduction.

The first question is is the poor amplitude isolated to a single vertical position or is it in all?

if in all and you have sure that the balance and hairspring is centred and free in all positions then the most likely cause is excessive friction between the pivots and sidewalks of the jewels either in the balance or train, as this contact is reduced dial up dial down. Need to make sure that all the jewels and pivots are all scrupulously clean. Start with the balance and work your way back. 

 

[matabog]

Crown down is the worst. For the other vertical positions the amplitude decreases with about 20 deg.

Thank you for the answer!

[Gasman]

So the other vertical positions are OK as regards amplitude.

i would take another look at the balance itself. You need to use a high magnification and look closely at the balance and hairspring in the CD position to check that all is ok. it may still be a dirty Jewel with the dirt on the dependant side in the CD position but it is less likely.

Also look closely at the train in the CD position to check for any cause of increased friction.