I got this non-working 24-hour Raketa; the dial itself is in good condition, but it’s missing the second crown to rotate the ring with city names, the glass is broken, and it doesn’t work. I never took one of these apart yet so I wasn’t sure what I would find.
It quickly became apparent that the stem was stuck and couldn’t be removed, so I started disassembling the movement inside the case. Apparently someone used salad oil as lubrication – or some other inappropriate oil that polymerizes on oxidation – and it had turned into a solid sticky goo mixed with rust :/
The good news is that this side looks entirely interchangeable with any other Raketa 26** movement so any part that’s too far gone could probably be swapped out easily.
Eventually I got the stem out, and the movement out of the case. This is the back of the dial, the “world time” bezel, and the dial side, where things get interesting:
This large retaining plate is, as far as I know, unique to the 2623. On first glance it’s immediately obvious that the hour wheel is about twice the size of the one on a regular watch. So this is how you make a 24 hour watch; a different base plate and 2 different gears, everything else exactly like a regular 12 hour watch.
This is the dial side of a 2628 for comparison. A 2609 would be better, but I don’t seem able to find a good picture at the moment. The relevant difference is the size and position of the 2 brass colored gears (all the extra stuff is the date mechanism):
And here it is right after cleaning and swapping some parts: