Parennin x 171

[Gaus]

Good afternoon fellow forummembers,

I have serviced a Parennin x171 movement. I have replaced the mainpspring. The watch runs nice, but it looses time between 11:00 en 12:00 hours. What can be wrong? I appreciate your suggestions. With kind regards, Hans

[WatchMaker]

Does this happen once or twice a day ?

If once a day then it's probably something to do with the date changing mech not quite running smoothly and the 'drag' causing an issue.

If twice a day then put the crown in the time-change position and take a close look at the hour hand as your move it slowly around the dial ... does it sweep cleanly with an equal distance between it and the dial at all times? You just want to ensure that the dial is seated correctly and the hour hand was put back on level. If this checks out then be certain there isn't some some contaminate somewhere e.g. some fluff or dirt in between a tooth on the hour wheel.

[Gaus]

Hello Watchmaker, thanks a lot for this tips. I will check this and let you know.

[Gaus]

Hello watchmaker, I guess you're right with a problem with the date changing. Manually it looks oké. What can cause the "drag?".

[WatchMaker]

I'm not familiar with the Parennin specifically, and it's difficult to find much info on the web about this movement, so I'll need to talk generally...

A date change mech will normally consist of i) a wheel (or relevant mech) that pushes the date ring forward at midnight and ii) a date jumper that ensures that the date ring clicks forward neatly one day.

The date jumper is just a simple lever with a smooth curved end held lightly in position with a spring. When the date ring is pushed forward it slides over the next notch in the date ring and relocates. However if the original date jumper spring has been replaced with something that is too strong this can cause too much drag (or even prevent a date change) and affects the movement. This is the most likely initial cause and my suggestion to prove it would therefore be to remove the date jumper and spring and see if the date moves forward and the watch continues to keep time.

If however the watch still misbehaves at date-change time then we're to the mech that changes the date. You may need to post a picture or two to see if myself or someone else can spot the issue in that case.

[Gaus]

Oké, thank you.