Watch losing time at a specific minute mark

[PRLJAMR]

I have a watch that is timing fairly well on the timegrapher however the minute hand slows to a near stop when it reaches the 31 minute mark.  I know the amplitude could be higher and the beat error could be a little less however I’m not sure what is happening with the minute hand.  Any suggestions?  Thanks 

[watchweasol]

I would suggest you have a problem within the wheel train such as a damaged tooth, perhaps minute wheel , as a starting point check out the freedom of the train, min /hour wheels. as it is always about the same point.

[HectorLooi]

Check your cannon pinion, minute and hour wheel. Sometimes it's just a speck of dust or sometimes the cannon pinion might not be pressed down properly.

[Nucejoe]

  If the movement is cased ( as in the picture) minute hand might be rubbing on the glass, otherwise clean and inspect all parts mentioned above.

[clockboy]

If it has not been un cased then it is highly likely a train wheel issue. If it has been un cased the first check is the hands for clearance. 

[Nucejoe]

7 hours ago, Nucejoe said:

  If the movement is cased ( as in the picture) minute hand might be rubbing on the glass, otherwise clean and inspect all parts mentioned above.

So this happens once every minute, simply remove the minute hand ( the hand that goes round once every minute) this is a simple  process of elimination.

In case the issue persists, the fault is within the minute train and/ or date jumper.

 

[JohnR725]

23 hours ago, PRLJAMR said:

I have a watch that is timing fairly well on the timegrapher however

it would be nice to have background story? In other words you found this watch laying on the street and tossed it on your timing machine or you recently service this watch or what what's the background story of the watch?

Then one position timekeeping on the timing machine is not quite worthless but almost. Why don't you give us another picture crown down position just because. also the graphical display doesn't look quite as nice as it should be looking when was the last time the watch was serviced?

 

[PRLJAMR]

Okay - turns out it was a loose cannon pinion.  Thanks for all the recommendations!!