You would have to disassemble the dial side of the movement to access that mechanism. That mechanism is under the calendar.

 

Hello, I'm having the same problem of a broken crown stem. It is deep in the movement. I disassembled the dial side of the movement, can clearly see the stem, but cannot get it out. Could you tell me which part exactly holds the stem? Thanks a lot!

 

Thanks. Great video. And cool challenge ahead...

 

So outcome is: unsuccessful success... I've been able to take out the broken stem, but I killed the mechanism when re-assembling it! Not sure at which stage, maybe unappropriately putting back in place the escape wheel, but more likely at the pallet fork/balance reassembly stage.
I've also been unable to put back in place the day and date wheels, and I lost a screw...
At least something positive: now I know I cannot change the day and date wheels so I'm giving up on my plan to buy the cheapest movement as replacement and change these wheels myself.
Thanks again for your help.

 

I probably didn't emphasize enough in the earlier post that you only needed to "...disassemble the dial side of the movement." Just removing the calendar would reveal the mechanism that holds in the stem. You could have left the other side intact...

The things you broke are common for newbie watchmakers. Congratulations for having learned to do this task.

 

😜

Actually I went further than your reco because the way the stem was broken did not allow me to take it out from the dial side. Anyway the mouvement was not usable with the broken stem inside so no further loss overall.

 

Which part of the stem is broken?
Pictures showing the stem and the rest of it in the movement would be helpful.

 

Reviving this thread from the dead. I have this issue with two Seiko movements (similar ones think NH35a/NH36, etc. I can't think of anything common to the two failures except suddenly the stems won't go all the way back into the watch. I'm guessing whatever the pointy end is supposed to fit into has been bumped out of place while the stem was out.

Can that be gotten to from the dial side?

Anyone have an exploded view of that sort of movement, showing which way is best to try to fix this issue?

TIA!