The watch is fully wound, left to rest for 30 minutes and tested for performance in 3 positions. The positional variations are fairly good varying between -2.0 and +14.5 seconds per day but the amplitudes are low at under 230 degrees and the beat error is too large at 1.3 ms. Unusually, the horizontal position does not have higher amplitude than the verticals so, there is an issue.
Reviewing the rear (top) of the movement under the microscope shows a little corrosion on the regulator but the balance jewel has oil. It is, however, dirty and with oil outside the jewel.
This has a nice Breguet hairspring and the shape looks good.
Other jewels are virtually dry but fairly clean.
And the visible wheel teeth look good at first look.
Although the escapement is dirty with oil on the escape wheel spokes.
There is nothing obviously wrong so, after quoting for a full service and that being accepted, the strip down starts in the next post.