IWC automatic from 1975 cal. 8541b.

I am the happy owner of this watch. It works perfectly in the daytime when I am carrying it.( without winding it at all). But when I take it off at night it will only work for appr. 3 hours, then it stops. It should have a reserve of 44 hours?? I have tried to wind it when I take it off at night - it does not help.
What is wrong??
greetings boerge from Denmark.

Without physical examining it, we can't tell for sure. I suspect the mainspring is caught, and only winds minimally --enough so that the Pellaton winding system rocks enough to keep the watch wound sufficiently when you wear it.

But --something is broken, and you need to get it fixed. Good luck.

Hello again,
Thank you for a good answer, I will contact a good watchmaker and get it fixed and get the watch serviced. Do you have any idea of what it will costs if it is the problem you mentioned?

kindly regards from Denmark. Boerge.

Hello again,
Thank you for a good answer, I will contact a good watchmaker and get it fixed and get the watch serviced. Do you have any idea of what it will costs if it is the problem you mentioned?

kindly regards from Denmark. Boerge.

Hello again,
Thank you for a good answer, I will contact a good watchmaker and get it fixed and get the watch serviced. Do you have any idea of what it will costs if it is the problem you mentioned?

kindly regards from Denmark. Boerge.