Lejour 7765 Chrono - stops running after engaging the second hand

[chicane]

I have a very nice LeJour 7765 Chrono (Heuer based). The watch runs like a top if the second hand is not engaged and I can occasionally get it to work for hours with the second hand engaged. But by and large it stops moving on or near the 12 o'clock position after engaging the second hand for one minute.

Any ideas on what this might be and how to remediate?

[nickelsilver]

If it stops with the seconds just before 12 it's likely an issue with the minute counter- somewhere between the minute counter jumper and the finger on the chronograph runner.

Often it's that the jumper tension is too high, but could be a handful of things.

[chicane]

4 minutes ago, nickelsilver said:

If it stops with the seconds just before 12 it's likely an issue with the minute counter- somewhere between the minute counter jumper and the finger on the chronograph runner.

Often it's that the jumper tension is too high, but could be a handful of things.

Thank you for your response.

Could you tell me how to reduce the jumper tension?

Also, could you tell me what the other potential causes could be?