Sunbeam Cordless Electric Wall Clock

Movementman

Registered User
Oct 30, 2012
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I bought this a few days ago on Ebay, and it just arrived about an hour ago. It is a Sunbeam cordless electric clock with a Jeco tuning fork movement in it. This is the newest out of my Jeco movements because this one has more plastic gears than my other two have. It has a sticker on the inside of the glass for the Antique Automobile Club of America that I believe was put on some time after the clock was fisrt bought. I cleaned it up the best I could for now, but I will clean it a bit more when I have more time. It still runs great and seems to have survived the post office. I have attached 5 pictures. View attachment 253195 View attachment 253196 View attachment 253197 View attachment 253198 View attachment 253199
 

Movementman

Registered User
Oct 30, 2012
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For some reason all but the first picture wont load for me, let me know if they work for you...
 

Tinker Dwight

Registered User
Oct 11, 2010
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Calif. USA
I get none of them.
Are these pointer to a photo box or did you download the
actual jpg or whatever.
I had to look them up. They seen to work on a variation of the
Sully reverse escapement. That first wheel turns really fast.
Tinker Dwight
 

Movementman

Registered User
Oct 30, 2012
61
0
6
I get none of them.
Are these pointer to a photo box or did you download the
actual jpg or whatever.
I had to look them up. They seen to work on a variation of the
Sully reverse escapement. That first wheel turns really fast.
Tinker Dwight
It seemed to work this time. It didn't seem to upload them even though I told it to. You should get them now. The first wheel turns fairly quick, maybe a few hundred RPM. These use a magnetic escapement and are not self starting, but are started by pulling and releasing the time set knob.
 

Tinker Dwight

Registered User
Oct 11, 2010
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Calif. USA
One wonders how the self starting ones work.
Unlike a synchronous motor, there is no initial
torque to get then started in the same way. The
tuning fork gradually builds up in amplitude
and always at the same frequency.
Cool idea.
Tinker Dwight
 

Movementman

Registered User
Oct 30, 2012
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6
One wonders how the self starting ones work.
Unlike a synchronous motor, there is no initial
torque to get then started in the same way. The
tuning fork gradually builds up in amplitude
and always at the same frequency.
Cool idea.
Tinker Dwight
I personally really like these things. I think that the self starting ones are a lower frequency so they might have a bit more torque than these ones, if you get what I mean. These are very reliable and pretty accurate so I use them. I put one of these movements in an older Verichron Quartz clock case last year because the original movement was shot. Besides, the smooth second hand looks better on that clock because the seconds are split into smaller parts. It has been running perfect for about a year with just a little speed adjusting, but otherwise accurate.
 

Movementman

Registered User
Oct 30, 2012
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I adjusted it so now it has not gained or lost more than 1/2 a second for about a week. It seems to bee more accurate then most quartz clocks I see.
 

Tinker Dwight

Registered User
Oct 11, 2010
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Calif. USA
Gone are the days when a quartz clock is properly
tuned.
Most do what is called a digital tune.
I am fine tuning my new-old Seiko transistor clock,
right now.
I'm seeing about the same mount of daily variation
on the going rate. It uses a balance wheel of the type
used on many of these single transistor drive clocks.
I'm quite happy with it as it has a world time dial.
What is it that you look for to find one like your clock
with the tuning fork? Most of these newer looking clocks
are just regular quartz movements.
Tinker Dwight
 

Movementman

Registered User
Oct 30, 2012
61
0
6
Gone are the days when a quartz clock is properly
tuned.
Most do what is called a digital tune.
I am fine tuning my new-old Seiko transistor clock,
right now.
I'm seeing about the same mount of daily variation
on the going rate. It uses a balance wheel of the type
used on many of these single transistor drive clocks.
I'm quite happy with it as it has a world time dial.
What is it that you look for to find one like your clock
with the tuning fork? Most of these newer looking clocks
are just regular quartz movements.
Tinker Dwight
I figured that it gained 10 seconds in a 5 days so I adjusted it, then it was slow by a couple seconds, than I did it again and than one more time. After about 2 days I found the sweet spot and it has drifted about 1/4 of a second according to my cable box over about 1 week.
I typically only look for AC clocks, but the older quartz and transistor movements are very interesting to me. The tuning fork movements are interesting to me because of how they work. When I look for specific types of clocks, I just keep looking around and they turn up eventually.
I have seen this same clock with quartz movements, electric, and various electronic movements on them, but most commonly electric movements. This clock would date back to the mid-to-late seventies with this movement on it. With some patients and time, these older electronic clocks can be just as accurate as quartz or synchronous clocks.
 

Tinker Dwight

Registered User
Oct 11, 2010
13,666
72
0
Calif. USA
I finally got a clock with one of these movements. I hadn't fully
realized how these worked.
They are really clever. There is nothing mechanically connecting
the tuning fork to the "escapement wheel".
The tuning fork has two small magnets, one on each side of the
escapement wheel.
The escapement wheel has teeth and below each tooth is a slot.
the wheel is made of steel.
As the tuning fork vibrates towards or away from the escapements
arbor, it attracts either the tooth, in one direction, or the metal between
the slots, in the other direction. The solid part is right below
the gap between teeth.
Once the wheel is spun, by a starting kick, it will stay synchronous
to the tuning fork. One each cycle, it moves to the next tooth
or the next solid part between the teeth.
The clock I got had battery leakage damage that had not been properly
fixed. I did some cleanup and replaced the hacked wire. It seems
to run really well.
The movement is also a Jaco and the clock dial says Boluva and has
the little tuning fork symbol as seen on the watches.
Tinker Dwight
 

dAz57

Registered User
Dec 7, 2011
2,018
30
48
sydney Australia
Country
Region
Yep, Jeco licensed to make theses from Bulova, these Jeco movements turned up in lots of different clocks, even Smiths made one which was actually a Jeco, they were probably the most accurate clock available until quartz came out, they were a well made solid movement, easy to service, the main problem with them is the index wheel pivots would dry up and it would chew the pivots off, so just make sure to clean the pivots well and peg out the jewels cups and use a good quality oil.
 
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