Recently I got a Sankyo 432 that was not running. This has the Telechron like sealed can field coil motor, like many other Sankyo clocks (see this list) as well as other clocks that use the Sankyo mechanism.
During the repair I learned a few lessons that I like to share.
Lesson 1: the “heat it up and apply some force to the outgoing axle” method to get it going is not a good idea on the Sankyo motors
Inspired by this video I used this method (but turning the gear by hand, not with pliers!) on a few canned motors, also Sankyo motors, with succes. This time though it did not work. I got movement on the axle, but it did not feel right and it still would not run when powered. In the end I opened up the motor and it appeared that a gear had broken. Unlike the Telechron motors that have all metal gears, in the Sankyo motor there are a few plastic gears. The one on the rotor axle appeared to be made from a brownish plastic the had gotten very britl and disintegrated.
In the proces though I learned:
Lesson 2: you can open up a Sankyo sealed can motor for service
With the first motor dead, and still wanting to se my 432 running, I decided to cannibalise one of my “lesser” clocks (an Intel 42/301) for another motor. This motor was running but very noisy. Now knowing what a mess it can be inside I decided to open it up and properly service it. Here is how:
Step 1: remove the seal
This is a time consuming step. The white seal is hard and the aluminium is soft. I tried all kind of sharp tools but with any of them it still was an endless slow scraping and grinding. Sometimes you’re lucky and bigger chips come off, but most of the time it is a tedious slow proces. I did not dare to use any powered tool like Dremel or a drill for the risk of damaging the case. If anyone knows a better way, please let me know!
Step 2: get the mechanism out
With the seal removed the mechanism sits still tight in the case and there is little to get a hold on to get it out. Just pulling on the axle won’t do. This puzzled me for a while, but then I found this trick worked: gently tap the edge of the case with the handle of a screw driver or something alike. Tapping round and round the edge will slowly move the mechanism towards the edge of the case. Once there a little pull on the axle is all it needs to get it out.
Step 3: clean
Using alcohol and a small brush I removed the remains of the old lubrication.
Step 4: Relubricate
I used synthetic motor oil, but judging by what I read on all kind of forums I think any light oil will do. I was a bit unsure how much oil to apply. I certainly think you should not drown the thing in oil since that will give too much resistance. On the other hand, there are I think what seems to be “capillary plates” on each side. These are intended to hold some oils by capillary force in place such that the axle ends are always lubricated, so since these need some oil too you should also not apply too little. I applied about two drops per axle.
Step 5: Straighten the rotor
The rotor discs are easily bend by all the handling needed in the proces up till now. Any misaliigned may cause vibration and thus noise. So better straighten up these discs now you can.
Step 6: Reassemble and test
Insert the mechanism in the case and in the coil and let it run for a while. Just to make sure there aren’t any problems before sealing it up.
Step 7: seal the can
I used an epoxy adhesive to seal the can. This was a transparent epoxy which makes it a bit hard to see what you are doing, but other than that, it did the job.
Done! It has been running silently for two weeks now.
This is the first time I did this, so any ideas that may improve this procedure are very welcome!
During the repair I learned a few lessons that I like to share.
Lesson 1: the “heat it up and apply some force to the outgoing axle” method to get it going is not a good idea on the Sankyo motors
Inspired by this video I used this method (but turning the gear by hand, not with pliers!) on a few canned motors, also Sankyo motors, with succes. This time though it did not work. I got movement on the axle, but it did not feel right and it still would not run when powered. In the end I opened up the motor and it appeared that a gear had broken. Unlike the Telechron motors that have all metal gears, in the Sankyo motor there are a few plastic gears. The one on the rotor axle appeared to be made from a brownish plastic the had gotten very britl and disintegrated.
In the proces though I learned:
Lesson 2: you can open up a Sankyo sealed can motor for service
With the first motor dead, and still wanting to se my 432 running, I decided to cannibalise one of my “lesser” clocks (an Intel 42/301) for another motor. This motor was running but very noisy. Now knowing what a mess it can be inside I decided to open it up and properly service it. Here is how:
Step 1: remove the seal
This is a time consuming step. The white seal is hard and the aluminium is soft. I tried all kind of sharp tools but with any of them it still was an endless slow scraping and grinding. Sometimes you’re lucky and bigger chips come off, but most of the time it is a tedious slow proces. I did not dare to use any powered tool like Dremel or a drill for the risk of damaging the case. If anyone knows a better way, please let me know!
Step 2: get the mechanism out
With the seal removed the mechanism sits still tight in the case and there is little to get a hold on to get it out. Just pulling on the axle won’t do. This puzzled me for a while, but then I found this trick worked: gently tap the edge of the case with the handle of a screw driver or something alike. Tapping round and round the edge will slowly move the mechanism towards the edge of the case. Once there a little pull on the axle is all it needs to get it out.
Step 3: clean
Using alcohol and a small brush I removed the remains of the old lubrication.
Step 4: Relubricate
I used synthetic motor oil, but judging by what I read on all kind of forums I think any light oil will do. I was a bit unsure how much oil to apply. I certainly think you should not drown the thing in oil since that will give too much resistance. On the other hand, there are I think what seems to be “capillary plates” on each side. These are intended to hold some oils by capillary force in place such that the axle ends are always lubricated, so since these need some oil too you should also not apply too little. I applied about two drops per axle.
Step 5: Straighten the rotor
The rotor discs are easily bend by all the handling needed in the proces up till now. Any misaliigned may cause vibration and thus noise. So better straighten up these discs now you can.
Step 6: Reassemble and test
Insert the mechanism in the case and in the coil and let it run for a while. Just to make sure there aren’t any problems before sealing it up.
Step 7: seal the can
I used an epoxy adhesive to seal the can. This was a transparent epoxy which makes it a bit hard to see what you are doing, but other than that, it did the job.
Done! It has been running silently for two weeks now.
This is the first time I did this, so any ideas that may improve this procedure are very welcome!
Comment