After two years running my beloved Sankyo 535L started to play up. It stopped now and then, and as now and then became ever more often, time came to do something about it.
This clock is battery powered and has what I call a "self winding mechanism". In short it has a conventional spring driven escapement mechanism that runs for a minute and then triggers a switch that powers a small DC motor. This motor then does three things: forward the drum wheels by one minute, wind the spring, and switch itself off. And from there the next one minute cycle starts.
After some investigation I found the issue was in the DC motor and when opening up the motor it became clear: the brushes had worn away.
It would have been easiest to replace the motor with the exact same model, but I could not find any online. I guess these are already out of production for a long time. Also the mounting bracket that is integral part of the motor seems to be specific for the clock mechanism which makes these motors even rarer.
So instead I replaced it with the slightly smaller Mabuchi RF-130CH motor from AliExpress (This is the same motor I used to repair my Twemco BQ-50. I bought a few of these, so I had it already in stock). Replacement was simple in principle but making a mounting bracket for the motor took me some time. It is just simple piece of bent metal, but getting all the holes positioned correctly such that the gears align required some attempts.
Below is a picture of the new motor in place during a trial run (normally the whole mechanism is hidden behind a metal cover).
The clock has been running fine now for a few days and runs even a bit quieter!
This clock is battery powered and has what I call a "self winding mechanism". In short it has a conventional spring driven escapement mechanism that runs for a minute and then triggers a switch that powers a small DC motor. This motor then does three things: forward the drum wheels by one minute, wind the spring, and switch itself off. And from there the next one minute cycle starts.
After some investigation I found the issue was in the DC motor and when opening up the motor it became clear: the brushes had worn away.
It would have been easiest to replace the motor with the exact same model, but I could not find any online. I guess these are already out of production for a long time. Also the mounting bracket that is integral part of the motor seems to be specific for the clock mechanism which makes these motors even rarer.
So instead I replaced it with the slightly smaller Mabuchi RF-130CH motor from AliExpress (This is the same motor I used to repair my Twemco BQ-50. I bought a few of these, so I had it already in stock). Replacement was simple in principle but making a mounting bracket for the motor took me some time. It is just simple piece of bent metal, but getting all the holes positioned correctly such that the gears align required some attempts.
Below is a picture of the new motor in place during a trial run (normally the whole mechanism is hidden behind a metal cover).
The clock has been running fine now for a few days and runs even a bit quieter!
Comment