This is the watch in a non-functioning state. The plan is to re-finish the dial myself once time & finances allow.. The problem does appear to be with the hairspring and the balance - the two aren't connected very well.
Before I started tearing this thing apart, here are some photos of the Russian workhorse, an example of 1940s Swiss design that 'magically' migrated east in the subsequent decades.. This is the obverse of the movement, removed from case. The simple 2 position clutch mechanism has an annoying spring which is very hard to set (under the dotted plate).
The movement is in overall good condition. Apart from some rust on the regulator stem and the hairspring collet, its clean and fine.
The reverse with the balance cock, and the balance removed.
The reverse with the gear train bridge removed.
The reverse with the pallet fork cock removed.
The reverse of the plate with the mainspring bridge removed. This picture shows the flow of power from the mainspring barrel, through the centre wheel, third wheel, fourth wheel, escapement, and then the pallet fork. The energy is released in an incremental manner by the oscillating balance.
The reverse of movement plate almost bare, except for the center wheel - which is connect to the cannon pinion on the obverse.
The obverse of the movement with the clutch partly disassembled.
The movement (mostly) disassembled for cleaning - a combination of ultrasound & shellite/naptha/benezine
The problem. The c-ring that should crimp the balance spring to the balance shaft is loose. Usually this requires very expensive and very precise tools (which I currently don't have...), this would make the exercise futile given the very low value of the watch. However, with my handy loupe & a leatherman (I know, I know..), I re-crimped the c-ring the shaft successfully....
Balance spring and shaft re-attached.
The reassembled movement ticking away accurately, with no slippage on the balance shaft. Now keeping (quite surprisingly) accurate time.