Miyota Automatic Service - "three Screws To Rule Them All"

[Lawson]

Miyota Automatic Service - "Three Screws to Rule Them All"

 

 

Now for something completely different, a Japanese Automatic from Miyota.

 

This is a budget driver's watch from a fashion brand called Scorpion, and I had no idea what I'd find when I removed the caseback  :huh:  Whatever!  I just wanna work on watch movements, increase my knowledge, and the repertoire of movements I've had experience with.  It's also a blessing to post these to help people with reference photos and walkthrough of various movements.

 

 

When put on the timegrapher, it was quickly obvious that this movement was not running well at all.

Extremely low amplitude, high beat error, and a graph that looks like the pepper in your mash potatoes :P

 

 

Well, it happened to be a Miyota Automatic Movement ... I have no idea of the caliber, as there are no stampings on any of the plate ... beside the brand name.

 

 

Once removed from the case, I pulled the Hands...

 

 

...and then the Dial.

 

 

After that, I flipped it over and removed the oscillating weight to get a better look at the movement itself.

Notice anything scary about this already??

 

 

There are only 3 screws holding the complete movement together!! :o Ack!!  Visions of the Seiko 5J22A Kinetic "Auto Relay"  , with it's 9 pivot gear train plate flashed before my eyes!!  This was NOT going to be fun putting back together :P  But I do so love a challenge.

 

As per usual, I removed the tension from the Mainspring, and removed the Balance and Fork.

Note: The red arrow is pointing to a very thin spring which you pull back to disengage the Click.

 

 

Here's a closer reference photo of it after I'd pulled the plate off

 

 

So as the title says ... Three Screws to Rule Them All .... Bam!  The whole movement has to be located into ONE plate, that's only held by three screws ... this is not Rolex quality gentlemen ^_^

 

 

After tipping the movement up-side-down and telling the complete movement fall onto the desk (just kidding), you are left with only the Centre Wheel.

 

 

Once the Centre Wheel Bridge was removed, the fault with the movement running so badly came to light ... RUST on the lower piviot!

 

 

Rust also on the Pinion

 

 

Over to the Calendar and Keyless Work ... looking way over complicated for a simple Date Wheel, as all the springs are there for a day complications as well; minus just the Day Wheel :( ... Gotta love cheap movements.

 

 

Reference photos of the Keyless Work.

 

 

One last thing to note with this movement.  The setting lever is riveted into the Main Plate, so it's not able to be removed.

 

 

Well this little gem is in the Watch Cleaner, and I've got a few weekend chores to do, so I'll put it back together tonight and post the results later.

Hope you enjoyed this write-up, and got a few giggles out of it as well :)

 

[WillFly]

Fascinating. You'd wonder why - given the overall engineering of the main plate - the setting lever would be riveted in. For want of a screw...? Miyota were certainly being economical with screws on this one!

[Geo]

Another job well under way with excellent reference photos!

[Lawson]

Assembly

 

The rust that was on the Centre Wheel and Pinion cleaned up real nice,

 

So the first step was putting all the Gear Train, Mainspring, Winding Gears, and the Automatic Work onto the Main Plate, and then locate all those pivots once the Bridge was placed on top ... this movement is a good test of your patience and skill :)

 

 

As it's not possible to wind up the Mainspring for testing the Pallet Fork, I decided to install the Keyless Work so I could wind it up

 

 

While I was on this side I also removed the shock system and oiled it.

 

 

It's a very interesting system, and extremely easy to clean and re-oil ... perhaps the easiest I've come across.

 

 

Flipped the movement and installed the Pallet Fork and Balance ... then cleaned and oiled the shock system on the Balance Cock.

Started ticking straight away with very nice amplitude.

 

 

Next was the rest of the Motion Work and Calendar Work

 

 

Date Ring and Cover Plate back in place

 

 

Lastly the Dial and Hands replaced.

Again this movement used H3 tubes on the Dial and Hands, so very little clearance when fitting the hands.

 

 

Back on the Timegrapher ... and she's purring like a kitten :)

 

 

I thank the Lord Jesus Christ for the wonderful gift he has given me, I really enjoy this work, and every movement is an adventure.

 

I hope you've enjoyed it as well, and it helps those who come across this movement to service or repair.

 

 

[bobm12]

Hi Lawson,

 

Another jewel to the collection and watchmaking documentation. You, my friend, rock! By the way, I have a feeling this movement is a Miyota 8200 -- or variant -- I got the specs and happen to be working on them at the moment! So far I'm in the cleaning phase after disassembly! Cheers, Bob.

 

343_Citizen 8200,8210,8260,8270,8280.pdf

[clockboy]

I have said this before but in my experience the cheaper the movement the more potential problems.

Timex being a good example.

[anilv]

Don't worry, its not that bad!

 

Anil

[noirrac1j]

Hey thanks for the pictorial walk through of the Miyota. I've never done one, but have done many pin levers, and so am very familiar with having to locate all of the pivots over one plate--my self-imposed torture is complete on those!  The calendar works is very complicated indeed! It reminds me a little of a quick set day/date omega I did not too long ago. What type of timegrapher are you using by the way? 

 

JC

[Lawson]

bobm12, on 15 Dec 2014 - 03:14 AM, said:

Hi Lawson,

 

Another jewel to the collection and watchmaking documentation. You, my friend, rock! By the way, I have a feeling this movement is a Miyota 8200 -- or variant -- I got the specs and happen to be working on them at the moment! So far I'm in the cleaning phase after disassembly! Cheers, Bob.

 

343_Citizen 8200,8210,8260,8270,8280.pdf

 

That's the one Bob my old friend ... thanks for the PDF, it's neatly tucked away in my files now.

[Lawson]

 What type of timegrapher are you using by the way? 

 

JC

 

It's an Ace Timer 1000. Just a cheapie mate.

I just checked this watch on a $10,000 timegrapher, and the calibration on 1000's aren't perfect ... especially on the Beat Error, but you get what you pay for.

[perpetual92]

Sorry to dig up an old thread...but this write-up, Lawson, really has helped me. The reference photo of the gear train layout was just the ticket.  I'm lousy at reading part schematics so a photo to confirm saved the day.  I will say, the keyless works on the Miyota just seem, to me, more robust than on an eta 2824 I just had apart.

 

Now to figure out how to remove the Balance shock springs to service.  What tool did you use to move the ring?  I'm thinking of using a needle to drop in and turn it.  What did you do??

 

Thanks again, Lawson, for all your write ups on movement servicing.  Many of us really benefit from them.

Edited November 15, 2015 by perpetual92

[rogart63]

Those movement are really nice to work on once u now how they are assembled . I think i did a teardown of a 8215 or something like that some time ago . I had a lot of old 8200 and 8205 movement in my spare parts box . They where great as all of the parts are interchangable . And if u ever need a part they are super easy to come by on Ebay .Only costing a few £ The balance jewel is easy just to twist with a sharp object like a tweezer or some old oiler . 

Edited November 15, 2015 by rogart63

[perpetual92]

I agree, they are decent to work on once you have tackled the train bridge for the first time.  A bit of a pain, but not that big of an issue.

The Balance's shock system are very easy, indeed, to service. 

 

When done, the movement was producing +5 s/d, 265amp and .1 beat error. Lift angle of 49.  Which is the correct Lift Angle for the 8215.

 

I look forward to a future service with the new 9015 to compare.

 

Thanks again to Lawson for this very helpful Miyota Service walk through.

Edited November 16, 2015 by perpetual92

[GeorgeClarkson]

Had I found this old thread sooner, my service of a friend's Tiffany & Co Atlas with an ETA 2892-A2 automatic movement would have been faster, and easier... This movement is pretty similar to the one I just serviced, which was not working due to the broken mainspring. I did find the relative PDF but it took a couple of hours, since I am not acquainted with Miyota movements at all (actually that one was my first).

 

The ETA 2892-A2 is fairly more "high end" than this one, but apart some aesthetic differences, it is very similar. The oscillating weight has a different way to be attached apparently (3 screws instead of 1, and you have to remove them from beneath the oscillating weight). Here a pic of the movement used in a Cartier Roadster watch:

 

Image courtesy of http://www.urdelar.se/

[bobm12]

Hi George,

 

Apart from some similarities I find on and off in many watches from different makers, I fail to see what a Japanese Miyota 8200 and an Swiss ETA 2892 has to do in this walkthrough. Maybe you can point out what you found so helpful so your interesting post has more meaning to me. I'm all for learning...

 

Thank you for the enlightenment in advance,

 

Cheers,

 

Bob

[GeorgeClarkson]

Like perpetual92 before me I found the pictorial description very useful, and did something similar with the Eta movement myself, so actually I was not comparing the cheap Miyota with the swiss Eta, but only commenting on the methodology used to service the Miyota: I am basically learning by doing and a pictorial walkthrough, no matter on what movement is based, is always very helpful for me. Hope this clears my enthusiastic comment.

Hi George,

Apart from some similarities I find on and off in many watches from different makers, I fail to see what a Japanese Miyota 8200 and an Swiss ETA 2892 has to do in this walkthrough. Maybe you can point out what you found so helpful so your interesting post has more meaning to me. I'm all for learning...

Thank you for the enlightenment in advance,

Cheers,

Bob

[bobm12]

Thank you George,

 

Sorry, I thought you were talking about something of note in the movement or service that would make this walkthrough pertinent to/appropriate for the ETA movement...

 

Me too, I find all walkthroughs very helpful and Lawson's walkthroughs in particular tend to highlight many interesting and sometimes overlooked details and techniques (extras) that add to the already wealth of educational material involved.

 

Cheers,

 

Bob

[GeorgeClarkson]

No worries, Bob, I was probably writing too enthusiastically and forgot to mention the reasons I was writing... I love movement pictures, I could stare at them for hours! Pictorial walkthroughs are just the reason I subscribed to this forum (apart from the videos, which I find excellent but "harder" to follow sometimes - I cannot study a video still image as accurately as a high definition picture).

 

Lawson's walkthroughs in particular are excellent: hi-def pictures, excellent description and some humor to mix it all up. Just great.

 

 

Thank you George,

 

Sorry, I thought you were talking about something of note in the movement or service that would make this walkthrough pertinent to/appropriate for the ETA movement...

 

Me too, I find all walkthroughs very helpful and Lawson's walkthroughs in particular tend to highlight many interesting and sometimes overlooked details and techniques (extras) that add to the already wealth of educational material involved.

 

Cheers,

 

Bob

[GeorgeClarkson]

BTW, I just serviced a Skagen 755XLSLB automatic watch that has  Miyota 8215 movement, so once again I found the walkthrough very useful (and this time for the proper reasons ;) )

Edited November 17, 2015 by GeorgeClarkson

[xzqt]

I have tried servicing a 8215 before, it is pretty difficult to get the bridge onto the pinion.

You are correct that its a test of skill and patience.

 

*i still prefers the Sii movt.

Edited November 19, 2015 by xzqt

[Giumollo]

Almost 4 years old but this post saved my day!

No way I could have the calendar works back together without these pics.

Thanks!