Need advice repairing a Copal II motor

[Reaper]

I just picked up a GE 7-4305F flip clock pretty cheap. It was advertised as "working" but it wasn't exactly working well. When I got it the bulb was very dim so I replaced it, and all the switch contacts and volume knob needed a good cleaning. The motor was barely turning so I took the metal cover off of the back and noticed it was a Copal II. I dipped the rotor part in a shot glass full of 99% rubbing alcohol and shook it around. When I lifted it out the alcohol was full of small brown particles. I spun it out and dried the motor with compressed air and tried it again. The motor ran perfectly and completely silent for a while, then started to get noisy and slow down a little. I cleaned it again until barely any dirt came out of it and put it back together.

Overnight the clock lost almost 2 minutes and began to get noisy again. I was going to try spraying lubricant into the rotor part and working it in, without getting any into the gears. Then remove the excess by laying it on paper towels and spraying the motor with air. I have some 3-in-1 professional silicone lubricant in a spray can. It's light and penetrating and dries quickly. It's also safe on plastic, vinyl, and rubber. Would this be suitable to lubricate the motor? Also, should I spray some into the gearbox? It's riveted onto the motor so I can't take the cover off to clean it out. Normally vinyl gears don't need lubrication but I wasn't sure. What about the main metal gear that connects to the clock mechanism? Should that be lubricated?

[flipoclock]

Not sure about the oil, but surely someone can comment on it.

You CAN actually open up the gearbox and put it back together again. You need to carefully pop loose all 3 rivets. They pop away from the gearbox and do not require much force. Do take care that on one individual motor you can perform this action 2, maybe 3 times before the 'rivets' wear out and will not hold anymore.
Also, bear in mind that you need steady fingers and a clean table cloth since you will be working with small gears and tiny shafts.

Lastly, remember to take pictures while working! Should something fall apart in bits, you will not naturally know where to put everything back :-) I learned this through experience :

[Mackey]

There are various technical manuals out there (somewhere, I've seen them) that do indicate lubrication of the gear or type of gear you specify is ok (haven't seen one for your specific model).
As far as that copal motor, all it is is a winding, and an axle connected to the rotating (external) rotor. I'm not sure about using the drying type lubricant. The rotor axle has very little space to move around inside it's bushing there. I think a good quality liquid oil is best here. Some here have actually used synthetic motor oil with good result. A former member recommended it and I can assert that it works well. But really any good oil would work, I think.

[Reaper]

I used the silicone lubricant by spraying the motor part full to make sure I reached the shaft. Then I removed all the excess with my air compressor on low pressure so only a thin film remained on everything. The oil was too thin for the motor and it made a vibrating noise. If you hold onto it the rotor can be moved in and out a little and very slightly side to side. I'm not sure if there's supposed to be any play in it or if it's worn out. So then I tried a hobby oil I had with teflon in a needle applicator. I put a few drops in the holes on the back of the rotor and let it run down to the shaft. Then I put a small chip in the gearbox casing so I could get the needle in there. I put a few drops directly on the main gear and the other side of the shaft and worked that in.

The vibration is gone now with the thicker oil and the clock seems to be keeping time. However, if you listen closely while near the clock you can hear what almost sounds like a fast clock ticking but more of a knocking sound. I assume it's the sound of all the mechanisms and gears being moved by the motor. The gears inside the gearbox are OK and the main gear on the clock assembly which connects to the motor is fine. Is this type of noise normal or is my motor worn? Maybe something in the flip mechanism needs cleaning or oil? My 7-4305C doesn't make that kind of noise but that's using a completely different clock mechanism and a sealed motor without a gearbox. The only noise that one makes is the typical "snake rattle" when strain comes on the motor to turn the tiles over. Maybe I might have to find a working clock and make one good one out of the two. This one was completely seized when I first got it.

[Mackey]

The only thing that comes to mind is the the rotor wheel is off balance and may be striking the shroud that covers it.
You're probably going to be better offing making the two from one as you mentioned.

[Dangermouse]

Thought I'd add to/hijack this thread rather than start a new one on a similar topic. I picked up a nice Copal Model RP-233 recently which is in aesthetically great condition but running very slow, like ten minutes an hour slow. I've done the alcohol dunk and tried oiling the motor but nothing I've tried has had any effect. The clock is really clean inside, the motor looks to be in fine fettle but it's still too slow to be of any timekeeping use. I'm in New Zealand and the clock is labelled as 50Hz but hey, who knows what could have happened to it in the last 30 years... Is it possible it's a 60Hz motor? Is that how it would behave in that case? I've got no reason to believe the motor has been replaced but I'm currently stumped. How easy would it be to find a replacement 50Hz motor for this beauty?

[RetroFlip]

Dangermouse Some gearboxes on copals have a switch for 50-60hz, even if labeled as 50hz on the case. Should be fairly obvious though, and say 50 60. Personally only seen those on 110v clocks for the Japanese market. This is a rear mounted motor, right?

[Dangermouse]

Rear mounted motor, yep.



I did find this label which must have been attached to the gearbox cover and fallen out on disassembly; seems to confirm a 50Hz motor all right so that mustn't be the problem after all.



I did find a loose solder connection to the alarm microswitch but that's hardly contributing to the slow running.

Anything else I might look at or try?

[flipoclock]

If you measure the time difference, it it like an exact number of seconds per minute? If it IS the wrong hertz, it should be exact.

On a different note, I should be able to supply you with a replacement motor, just send me a message.

[Reaper]

Just figured I'd post an update. I ended up scrapping this clock for parts. I just found a model I was looking for, a GE 7-4310F. When I received it there was a LOT of dust inside, and the motor sounded like it was screaming in agony! It had the same Copal II motor as my other clock, so I dipped it in alcohol to free it up. Then I put a few drops of 3-in-1 oil through the holes in the rotor and it started working fine. However, a few minutes later it started to get noisy again. I managed to carefully pry the plastic casing off of the gearbox. It actually just snaps on and clips in place. The problem is the plastic on these motors is *extremely* brittle. It cracked slightly on one side and loosened up enough for me to get it off. I put a small drop of oil just under the metal gear, directly on the shaft. The motor immediately got much smoother and now it works perfectly. I cleaned the excess oil off of the gears and snapped the cover back on, using clear scotch tape to hold the crack in place. It seems the only way to truly fix these motors is to get access to the side with the metal gear one way or another. Unless you can get at both sides of the axle you don't always get good results. Too bad there's no easy "trick" to getting the cover off.

Another thing I noticed is the main bulb on these clocks is held in place by a metal bracket in front of the clock, just underneath the numbers. The bracket reflects the light but it's not very shiny, so I covered it in aluminum tape to make it more reflective. It actually made a noticeable difference. This might be a good fix for someone wanting to brighten the display of their clock. Luckily the original neon bulbs in this clock were still clear and in good shape, they just needed to be wiped off. After much cleaning now I finally have a fully functional clock!

[flipoclock]

If you're looking to get red of the red/orange Copal clock, I'd definitively be interested... Send me a message.

[cthulhu]

I don't want to start a new topic, so I write here the issue I am struggling with. I properly lubricated the stuck Copal motor, which had obviously not been running for a long time. After that it helped a lot and it is running again, but there is a thing. In one place, the rotor seems to be slightly rubbing against the stator, so this irritating sound is produced, and it also doesn't always start up by itself after plugging in. If I move the rotor slightly and find a different position, everything is fine, but after a few minutes it always returns to the original position. I don't know if the reason could be some dirt inside the rotor, or if it's just the wrong position or deformation of rotor. Anyway, if anyone has struggled with a similar problem and managed to solve it, I'd be happy for recommendations.

[Johan de Jong]

I can think of two possible causes:

One is, as you said, the rotor is touching the stator. You might be able to solve this by readjusting the pins of the stator cage. See this post: https://www.flipclockfans.com/forum/...ttle-copal-225

Another possible cause is wear of the bearings causes it to run unevenly. I have seen exactly the behaviour you describe, and I'm not exactly sure what is going on in that case, but I imagine wear has cause the the hole in the bearing become oval or extend in one direction. In any case, not round anymore. When starting the motor it may run in a spot where it runs freely and then drift off to the spot where it has a lot of friction and then it stops. To determine if this is be the case you can hold the rotor and feel if is has a lot of room to move in the bearings.
You come at the right time as just a day ago I posted a solution to this problem : replace the bearings. See this post: https://www.flipclockfans.com/forum/...-a-copal-motor