Venus 188 beating erratically after restoration

[clockboy]

If all is OK up to the train of wheels running freely then it’s the mainspring or mainspring barrel has too much wear. Either can cause lack of power through the watch causing low amplitude.. If you know the caliber of the watch check it has the correct strength mainspring fitted. If you follow Chronoglide Watchmaking on youtube one of the vids shows what to check with mainspring barrels and how to fix.

[Neverenoughwatches]

9 hours ago, ifibrin said:

If it does stop abruptly where do you usually look? End shake, jewels, pivots, pinion, and wheel teeth? Is there anything else? I have one movement with acceptable amplitude but doesn’t show backspin and does stop somewhat abruptly.

Hi ifibrin.  The one I'm working on now that had low amplitude, so I put it away to come back to later. I returned  to it a few days ago for another  attempt, discovered there was very little endshake on the balance. I used a little trick Mark showed on one of his videos. Raising a dot under the balance  cock. The cock screws were positioned quite forward on the cock and were pulling it down . It worked wonders and almost doubled the amp . But in dial up position stalled. A check on the free train was showing no back spin, turned out to be a worn bottom pivot on the third wheel. This will be my first repivot project.

[Neverenoughwatches]

3 hours ago, clockboy said:

If all is OK up to the train of wheels running freely then it’s the mainspring or mainspring barrel has too much wear. Either can cause lack of power through the watch causing low amplitude.. If you know the caliber of the watch check it has the correct strength mainspring fitted. If you follow Chronoglide Watchmaking on youtube one of the vids shows what to check with mainspring barrels and how to fix.

Hi clockboy, chronoglide is one of the few I watch and trust. There is a video tour of his workshop, its amazing.  I've been trying to fix a movement that has had a load of issues. Finally pinned down to a worn train pivot and possibly  an oversized mainspring  that has been fitted at sum point in its life.