A couple of questions for our resident watchmakers

I hope someone will be able to point me in the right direction / let me know what could be wrong with 2 watches I own. Not in an effort to cut costs or corners on servicing but because I would like to know what might be the cause before I send them off for overhaul. - it’s always good to learn about what makes them tick.

First up I have a Omega flightmaster it keeps great time (within a constant - 15 seconds a day) and has a good power reserve (at least 35 hrs) It has an intermittent fault when the chronograph is run. It occasionally stops the entire watch. I.e. when the chronograph is engaged the watch will run but sometimes the chronograph will stop as will the entire watch. A quick shake and the watch restarts immediately. The watch does not stop if the chrono is not engaged.

Second up I have a PRS82 with the older movement. This no longer runs at all. It has sat untouched in my watch box since March and was running perfectly when I last wore it.
If you shake the watch the rotor spins and you get a stuttering movement of the second hand but for no more than a few seconds. Sometimes the second hand will stutter backwards when shaken. It winds but this does not spark the watch in to life. I am guessing broken mainspring? How it could have broken when sitting untouched in a box in a safe, I do not know.

Many thanks in advance and merry Christmas

John

Don't want to clutter you thread but I have exactly the same problem on a 321 cal Speedmaster . It's off to Simon Freese as soon as restrictions lifted but it would be nice to know for my own curiosity!
My thinking is a clutch problem or one of the hearts getting stuck!
Strange how both watches with different calibers presenting the same problem!

I’d say the depthing between the coupling wheel and the chrono runner is probably too tight and needs adjustment.

Thanks watchbloke , fairly common problem with these old watches ?

It’s not an unusual issue to find, the depth can be affected by a build up of grime on both wheels surfaces. The depth is checked once everything has been stripped, cleaned, inspected and reassembled to establish if adjustment is needed or whether it’s acceptable once again after the clean.

Depthing problems will stop the chronograph function running quite easily!

Thanks Duncan

That would make sense.