Service: Nivada With an AS 1802 Movement
It was impossible to wind this Nivada because it was already wound to the maximum. However, it didn’t run so it was stuck in this position.
Many would call it over-wound, although that’s not an accurate description. You can read more about why an over-wound watch doesn’t exist in this article.
The movement is an AS 1802. It’s an unusual movement because it has a friction pinion on the third wheel and the minute wheel is held under tension by a spring.
Remove all power from the mainspring. Move the click away from the ratchet wheel and slowly let the crown slip between your thumb and index finger.
Remove the balance assembly, the pallet cock, and the pallet fork.
Remove the ratchet wheel and the crown wheel with the crown wheel ring.
Remove the train-wheel bridge to gain access to the train of wheels.
Lift the escape wheel, the sweep second wheel, and the fourth wheel.
Remove the barrel bridge and lift the barrel.
Turn the movement around and start with the minute works.
Remove the cannon pinion cover and lift the cannon pinion and the minute wheel. As mentioned, the minute wheel is held under tension by a spring. Take a note so you can reinstall the minute wheel on the correct side of the spring during reassembly.
Remove the set lever spring and lift the setting wheel and the return bar with the return bar spring.
Loosen the set lever screw and remove the winding stem with the clutch wheel and the winding pinion.
That leaves the friction pinion on the third wheel.
I used the green Presto puller. Normally, you use it for cannon pinions, but it works with friction pinions as well. The third wheel will drop on the bench mat as soon as you remove the friction pinion.
Pre-clean the pivot holes and bearing jewels with a peg wood. This way, the hardened grease and dirt are removed as much as possible to be cleaned more efficiently.
Clean all the parts in the watch cleaning machine. Six minutes per bath and the heating chamber will do the trick.
Install the new mainspring. Place the barrel back into position ans reinstall the barrel bridge.
Reinstall the escape wheel, the fourth wheel, the third wheel, and the sweep second wheel.
Install the set lever with the set lever screw.
The set lever screw doesn’t fit if you first install the train-wheel bridge. I forgot, so I had to install it twice.
Reinstall the combined bridge/train-wheel bridge.
Place the ratchet wheel and the crown wheel with its ring into position.
Don’t forget to lubricate the third wheel before you reinstall the crown wheel.
Flip the movement around and start with the minute work.
Firstly, the friction pinion. I lubricated it with some Molykote DX and used phosphor bronze tweezers to reinstall it to the third wheel.
Remember to install the minute wheel on the right side of the little spring that keeps it under tension. Install the cannon pinion and place the cannon pinion guard back in position.
Reinstall the winding pinion, the clutch wheel, and the winding stem. Place the return bar with its spring and the setting wheel in position and reinstall the set lever spring.
Flip the movement around and reinstall the pallet fork and the pallet cock. Give the crown a few turns and check if the pallet fork snaps to the next position with the slightest touch.
Reinstall the balance assembly and the watch should begin to run.
Clean and lubricate the jewel holes and the end stones from the upper and lower Incabloc shock blocs.
Install the hour wheel with the dial washer, reinstall the dial and the hands and recase the movement.
What do you think of this Nivada watch? Do you have a similar one in your collection? Let me know in the comments below.