watch stops with residual power

[east3rn]

Hello. I am a hobbyist watch fan. I have recently serviced my Molnija pocket watch with caliber 3602(hand-wound movement).

Watch was back in wonderful state (shown in photos) and ran roughly 40 hours during first day of test.

After couple of days, I noticed that the watch stops after running about 30 hours although it was wound fully.

I opened it up to check what went wrong and surprised to see that mainspring had substantial amount of power remaining.

I guess the mainspring had about 10 hours of power left. What do you think had stopped the watch? Please help. 

 

[Chopin]

Does it stop and no longer starts at all ? If you wiggle it around lightly does it start working again ?

[east3rn]

2 hours ago, east3rn said:

Hello. I am a hobbyist watch fan. I have recently serviced my Molnija pocket watch with caliber 3602(hand-wound movement).

Watch was back in wonderful state (shown in photos) and ran roughly 40 hours during first day of test.

After couple of days, I noticed that the watch stops after running about 30 hours although it was wound fully.

I opened it up to check what went wrong and surprised to see that mainspring had substantial amount of power remaining.

I guess the mainspring had about 10 hours of power left. What do you think had stopped the watch? Please help. 

 

 

13 minutes ago, Chopin said:

Does it stop and no longer starts at all ? If you wiggle it around lightly does it start working again ?

I tried shaking it but it won't run... any solutions? I think mainspring is the problem. I am considering lubricating it again. 

[Chopin]

Have you checked the pallet fork area ? With the mainspring charged if you try to move the pallet fork around does it re-start ? Or maybe rotating the balance a little bit...

[clockboy]

Its out of beat. It will run for longer when in beat.

[watchweasol]

Hi  I agree with clockboy  check the beat, on full power its overcoming the error as the power dimishes the error re asserts its self to  apoint where the movement stops. 

[m1ks]

In agreement with the above, I had this exact same thing happen on a movement after rebuilding the balance and cock, put it in beat and regulated it, (so I thought), then found after re casing it that it wouldn't run well once the spring had wound down a little and manually checked the impulse pin, it was way out despite the timegrapher initially looking OK.