After being sure the synchronar is really dead:
Strip the module from its components.
Cut all wire bondings to the IC.
And place a diode.
Next, kill a working ( in this case sanyo ) module and remove the display by putting a needle under it and gently heat up the display.
(I use a hot-air gun for removing paint from wood)
Once the display is hot enough the display will pop-off.
Next, test if everything will fit into the synchronars case, you probably need to remove some plastic.
Next, rewire the display.
Solder the display to the module.
Test if everyting is working OK.
Solder the module to the reed-switches and solarcells and put everyting in the case and test again and again.
Close the case with a little bit of glue and let it dry.
Pushing the right slider back shows time, pulling it towards you shows the date.
The left slider is used to set the watch, i removed the original left magnet so the watch can't be accidently set.
I now use a Pulsar magnet to set the watch.
And voila you now have a working "synchronar".
Well it is not original, but looks and feels the same :D