Stops after case ring installed??

[LittleWatchShop]

This is one of my 404 watches.

Thought it was done, but I discovered that with the case ring installed, the watch will stop relatively soon thereafter.

Remove the case ring and all is well.  I did this experiment twice--same result.

It is clear that when it is stopped, there is NO power getting to the escape wheel. Hmmmm.  I do not see where the ring could possibly touch any active element.

I show here the movement in the case and the case ring next to it.

[oldhippy]

I see it is a sweep seconds movement. Are you sure with that case ring fitted it isn't pushing the sweep second hand close to the glass? 

[LittleWatchShop]

2 minutes ago, oldhippy said:

pushing the sweep second hand close to the glass?

Excellent question.  I am not 100% sure, but I did look at it.  I installed a new crystal and it may not have the same height as the old crystal.

I will go back and investigate this further...it is probably the best path to troubleshoot.

Will report back soon!

[HSL]

Took a quick look too, it looks like a front loader. If it is you need to fasten it with the two case clamps which are missing in that picture, otherwise you will have that same problem regardless of which glass you choose.
The movement will just move freely back and forth just the winding stem hindering it to pop into the glass.

Edited July 5, 2021 by HSL

[LittleWatchShop]

1 minute ago, HSL said:

it looks like front loader.

No, it is a very conventional back-loader.

I have removed the movement from the case and attached the case ring (as if it were installed in the case) and have it on the bench watching to see what happens.

[HectorLooi]

Something doesn't look right with that case ring. There are screw holes on the plate for case screws, I guess that's why HSL thought it's a front loader.

Does the lug sticking out that case ring touch the balance wheel when the case back is put on?

[LittleWatchShop]

4 minutes ago, HectorLooi said:

Something doesn't look right

This appears to be a virgin assembly.  I see zero indication that anyone has ever worked on it before (screw slots perfect with no marring).  This assembly did not use case screws.

I just checked...the balance is far away from the lug by at least a mm outside of the case, but given the clearance, I would say it would not be able to reach the balance with the case back on.

More and more, I am believing the hypothesis of @oldhippy

[Nucejoe]

Some tests to eliminate possible faults.

Remove the crystal put the ring in and tighten back plate.

Of the four prongs of the ring, the one across the stem(180 degrees with the stem) can be pushing on train bridge, if so movement  should stop when you push on the bridge with your pegwood.

Bent dial plate can cause this too.

 

[LittleWatchShop]

OK, old crystal back on. In the case, with back snapped on.  Wait and see.

[LittleWatchShop]

OK it has been running nicely all afternoon.  I am going to declare @oldhippythe winner in this troubleshooting task.

Thanks for all comments.

Now I need a high-dome crystal...will work on that.

[LittleWatchShop]

Still running!

[KarlvonKoln]

One time, I got curious and used a dry-erase marker and touched it lightly to the seconds hand of a watch that wouldn't run in its case.  Checked the inside of the crystal afterwards for a spot of red.  Sure enough, there it was.

And dry-erase markers clean up spotlessly, especially with alcohol.

[LittleWatchShop]

1 hour ago, KarlvonKoln said:

used a dry-erase marker

Very clever!!