Bulova Accutron 214
In my article of the Bulova Watchmaster 600, I mentioned that I had a Bulova Accutron 214 that belonged to my departed father. I wished to restore it and decided to do the job myself. After doing some research and visiting watch forums, the consensus among the experts was that I should learn how to service mechanical watches before servicing Accutron’s. I decided to listen to them.
I’ve spent these last few months learning watch repair. I have also spent much time researching tools and their prices; new versus used and vintage tools versus newer style used, to get the best tools and most value for my limited dollars. Included with tools and equipment, I’ve also been acquiring factory Accutron service manuals and other watchmaking books including the “Chicago School of Watchmaking” course (CSOW), and “Watchmaking” by George Daniels.
It’s been a fun and interesting journey learning watchmaking. I must admit that it is more involved and more complicated than I envisioned at the outset.
The Bulova Accutron is a very interesting watch movement that was offered for sale beginning in October of 1960. I’ll give a brief summary of it but there is no need of me typing 20 pages when there is much information on the Net about them. Rob Berkavicius has a wonderful website about Accutron’s that has tons more information than I could put in a couple of articles. He also has a lot of info about various types of Accutron movements, including schematics and other interesting information. I recommend anyone interested in learning more about the amazing Accutron to visit his website.
The Bulova Accutron wasn’t the first electric watch utilizing a miniature power cell, which eliminates the need for a mainspring to power the watch. There were others that used the power cell however they still used the balance wheel and escapement mechanism for their time basis, which are the weakest part of the watch movement and the greatest source of trouble in a mechanical watch.
The Accutron uses a precise frequency standard, the tuning fork. The tuning fork with conical magnets inside the cups and the coils around them is controlled by an electronic circuit, thereby eliminating the balance wheel and escapement mechanism without adding complicated elements to the watch. There is an index arm with a tiny jewel at the end on one of the tuning fork tines that moves the index wheel to move the wheel train that is almost torque free since it doesn’t have the constant power of a mainspring pushing on them.
The Accutron tuning fork movement also minimizes positional error and eliminates isochronal error which is the fluctuation of power in a mechanical watch due to the status of a mainspring between fully wound down to its unwound state. It also reduces friction making the wheel train floating thereby reducing the dependency on lubrication. The tuning fork does not require lubrication, nor does the index/pawl jewels on the index wheel. Of course the wheel pivots need lubrication, but since they have such low torque on them and much less friction, the lubrication isn’t as necessary for the watch to keep good time.
It amazes me that the Bulova engineers could design and build the Accutron movement in the late 1950’s before modern computers and lasers! The 214 index wheel is only 95/1000 of an inch in diameter (2.41mm), and has 300 teeth!
The coil form has 2 coils that each use about 80 meters of 0.015mm diameter copper magnet wire at about 8100 turns, with approximately 25% of one coil used for the phase sensing coil. The phase sensing coil controls the pulses of current to the drive coils. The circuit controls the tuning fork frequency at 360Hz when everything is working properly.
In the next few photos you can see the fork cups, conical magnets, timing regulator tabs, and one coil form. I’m glad that I didn’t try to power the movement in the beginning since it is so filthy, as you can see. The magnets seem to still have plenty of magnetism which is a good sign. Besides being filthy, everything is looking good so far.
Below are some photos including close-ups of a tuning fork cup with the conical magnet, and one of the coil forms.
The above photo shows the left coil dial side up. At the top are the two wires that come from the one side of the Drive Coil 1 and one side of the Phase Sensing Coil that connect to the negative side of the battery. The bottom left side is the other side of the phase coil that goes through the green wire to the other coil hooking into the resistor/capacitors (one side of the 1nF) to the base of the transistor. The bottom right wire connects Drive Coil 1 and Drive Coil 2 through the red wire to the other side and connects with the other side of the 1nF cap. The other side of Drive Coil 2 connects to the emitter of the transistor. And the yellow wire goes from the positive battery well pad to the emitter of the transistor on the other coil side.
I don’t see any breaks in the wires anywhere. I’ll go ahead and close this article. In the next article, Bulova Accutron Part 2, we will take a deeper look at the electronic circuit and the indexing mechanism. I hope you guys/gals enjoy these articles. It’s looking like I’ll probably need three articles.
Robert Calk is a hobbyist from the USA who loves Electronics, Leatherworking, and Watchmaking. Please leave any comments you have below. Thanks.
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Please check out his previous repair article below:
https://jestineyong.com/sensio-bella-blender-repair/
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Parasuraman
May 20, 2017 at 4:32 pm
You took me to my higher secondary school days, when I learnt mechanical watch, timepiece and wall clock repairs from a neighbor, who was a Postman, doing this part-time family traditional job. I have repaired many of these during 1965 to 1968 period. That was my first exposure to outside the curriculum.
Good and very in-depth, informative article! Hat's off!
Robert Calk
May 20, 2017 at 10:41 pm
Thanks Parasuraman. The word "website" was supposed to contain a link to Rob's website. The link is: http://members.iinet.net.au/~fotoplot/acc.htm
It kind of makes me look stupid without it. Also "Bulova Watchmaster 600" was supposed to have the link to the article. I'm not very pleased that they were omitted.
Jestine Yong
May 20, 2017 at 11:48 pm
Hi Robert,
It was my mistake that I did not check the article and published it-sorry. I have just included the link.
Jestine
Robert Calk
May 21, 2017 at 12:20 am
Ok. Thanks Mr. Yong.
Jestine Yong
May 21, 2017 at 5:05 pm
Hi Robert,
You are welcome.
Jestine
sudhir
May 20, 2017 at 8:55 pm
HI Robert
Thank you for this informative artical and the passion for your chasing your dream.
now got the minute detail about the watch and its movement.
Thank you
Robert Calk
May 20, 2017 at 11:17 pm
Thanks Sudhir. It wasn't a dream of mine, it's just something that I thought would be fun to do, and also a good hobby to have.
Gerald Musy
May 20, 2017 at 9:07 pm
Hi Robert, I was waiting for this one and I am not disappointed. Excellent article and superb pictures.
Looking forward for the next one.
Cheers,
GM
Robert Calk
May 20, 2017 at 11:19 pm
Thanks Gerald. Maybe Mr. Yong can put the links back where I had them.
Jestine Yong
May 20, 2017 at 11:46 pm
Hi Robert,
I have just put in the link. Thanks for pointing out to me-sorry.
Jestine
Jean-Claude Picard
May 20, 2017 at 10:12 pm
Bonjour Robert,
Very interesting article, that also brought me some memories, for I was the owner of one of those accutron watch, that I had bought at a Wanamaker store in Pennsylvania a long time ago. I've sold the watch to my nephew who doesn't own it anymore, and i sincerely regret that sale. I wish I still own it, for it was a very interesting piece of electronic. Don't remember how much I'd paid for at the time surely a few hundreds dollars.PS. Excuse my poor English.
Robert Calk
May 20, 2017 at 11:27 pm
Thanks Jean-Claude. Your English is fine. My grandson loves to listen to my Accutron watch hum. I wear an Accutron 2182 that I will be servicing after I'm finished with the 214. I also have another 2182 that I'm going to service as a present for a friend of mine.
The 2182's will receive a complete service with new clear-coat and luminescence on the dial and hands.
Albert van Bemmelen
May 21, 2017 at 1:58 am
Indeed again another excellent article and superb pictures Robert! I've send this article by e-mail to my pro watchmaker friend Charles. Jestine is very busy at the moment because he forgot to email me the today's link with these new repair articles. They were just mailed to me by my good friend Erik.
Robert Calk
May 23, 2017 at 1:43 am
Thanks Albert, I'm glad you liked my article.
Anthony
May 21, 2017 at 8:34 am
Wow Robert....in another life you could have been a neurosurgeon! Very impressive work you have
presented here with great photos to match too ! This kind of work is too fiddly and beyond my
manual dexterity...but I certainly admire people like yourself who have the capability to perform it !
Thanks for sharing this article with us here and wishing you the best of success in restoring this
much treasured watch !
Kind Regards
Anthony
Robert Calk
May 23, 2017 at 1:46 am
Thanks Anthony. I don't think I could do it without a good microscope. My experience with electronics is very helpful when dealing with tiny components.
Yogesh Panchal
May 21, 2017 at 2:53 pm
Excellent!
Informative vintage collection article sir,
by the way photo quality is very good which camera you are using.
Robert Calk
May 23, 2017 at 1:56 am
Thanks Yogesh. Most of the photos are with my AmScope MU300 Digital Camera, and a few are with my Fujifilm FinePix SL 1000. The Fujifilm camera shows the date in the photos, but sometimes a comment box covers the date up.
John
May 22, 2017 at 1:34 am
Hi Robert
I have an accutron that my wife gave me on our 1st anniversary in 1964 I wear it to this day and it runs like it did when I first got it.
I used to enjoy the sound of the tunning fork but as the years have gone by my hearing has gone but I know that it is still humming as it keeps perfect time
This was a fine article
John R Phillips Jr
Robert Calk
May 23, 2017 at 1:58 am
Thanks John. I'm glad your Accutron is still humming wonderfully.
LaNell Barrett
May 22, 2017 at 3:11 am
Fascinating hobby. A science more than an art.
I do NOT trust the only watch repair person in my area. Though full of Pateks, Rolexs, and such....I have no idea where they take them for any type of service.
My watch, unworn for decades, is a lady's Bulova automatic I received new in the early 1970's. The ugliest watch ever, but I'd like it all to be cosmetically fixed. And checked for all else in case mechanically out of order.
Any suggestions. My USA zip is 34102.
Robert Calk
May 23, 2017 at 2:17 am
Thanks LaNell. Watchmaking is a great marriage of science and art. I'm just learning and don't have enough experience to recommend anyone. I would visit watch forums and ask people. You can google it and find people in your area and ask around. Maybe people you know or work with could recommend someone.
You can find information at the NAWCC here: http://mb.nawcc.org/index.php
And here: http://www.nawcc-index.net/RepairShopsUS.php
Humberto
June 4, 2017 at 8:27 pm
Hi Robert, good article and high quality photos. You have studied a lot and that is good for everybody. I,m studying Marketing nowadays.
Robert Calk
June 5, 2017 at 10:47 pm
Thanks Humberto. I'm glad you liked it.