Seiko 7A38 - by the numbers

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Forum Home > Bend it, Mend it - Mods & Wreckers > Deep inside a 7T32 (or Shiojiri Y182B) movement

GeorgeClarkson
Member
Posts: 508

Doing what most deem foolish, or just impossible, I usually tend to try to fix the Seiko 7TXX movements (32 - 36 - 39 series are all the same basically). Who has to repair a 7TXX watch usually does not care or dare to service it completely, and prefers to swap the broken movement with a working one, but these becoming more scarce and more expensive, it is slowly becoming not viable anymore. This is why I always try to service them, like if they were a mechanical movement.

The only practical difference being the fact that most parts of the movement are in plastic, you only need to take special care during the reassembly of the movement, and in particular replacing the train wheel bridge, since you can easily damage the tips of the wheels and the step rotors.

I made a series of videos showing how to properly (well, according to me) disassemble and reassemble the movement. Each video is approx 25 minutes long, due to the video camera memory card being not so big. So here it goes with the first 4 videos:


How to disassemble a 7T32 movement - Part 1: 

 

How to disassemble a 7T32 movement - Part 2: 

 

How to disassemble a 7T32 movement - Part 3:

 

How to disassemble a 7T32 movement - Part 4: 

 

Hope you enjoy!

--

My personal Blog: www.onlyvintagewatches.com/blog

April 9, 2015 at 3:32 AM Flag Quote & Reply

GeorgeClarkson
Member
Posts: 508

Paul corrected me on the name and manufacturer of the movement, which I had forgot to mention: actually this movement is a JEPIC Corp. Z7A movement out of a Puma Z7A001-70 with just a Shiojiri Ltd. stamped back-plate off a donor movement from a Pulsar Y182. Nevertheless, the movement is identical to the Seiko 7T32 and thus perfect for this project.



April 9, 2015 at 7:42 AM Flag Quote & Reply

Seiko7A38
Site Owner
Posts: 12380

Precisely, George. ;)

This is why the outer backplate (which you commented on as being surprisingly clean in your first video) shows little or no signs of the battery acid attack. In fact, the topside of the JEPIC Corp. Z7A backplate (which I retained and fitted to the working Shiojiri Y182B movement, for reasons of 'correctness') wasn't too bad - with just some minor discoloration, which cleaned up pretty well. :)


Here's the JEPIC Corp. Z7A backplate swapped over onto the Shiojiri Ltd. Y182 movement (still in the Pulsar case for the time being).




I'm going to leave your topic title as is - that way the thread (and your YouTube videos) is more likely to get the views it deserves ....

But I did correct your original mis-spelling of Shiojiri (you'd written Shijori). ;)


April 9, 2015 at 8:02 AM Flag Quote & Reply

GeorgeClarkson
Member
Posts: 508

I managed to post another couple of videos, here they are:

In Part 5 I reassemble the coils and check their resistance, after having installed the step rotors.
In Part 6 I finally complete the installation of all the wheels and parts, and proceed to replace the train wheel bridge, which is the most interesting part of the series of videos.

Part 7 will cover the dial side components, instead. It is still in the works, so please be patient.
--

My personal Blog: www.onlyvintagewatches.com/blog

April 11, 2015 at 2:13 PM Flag Quote & Reply

Sir Alan
Member
Posts: 457

Very informative George, I've enjoyed the first 4 videos, I'm sure I'll enjoy this next set.

I have several 7T34 movements that mostly work - I'm feeling like I might have a go at getting one good one going .......

April 11, 2015 at 6:03 PM Flag Quote & Reply

GeorgeClarkson
Member
Posts: 508

Thanks for the comments, Simon. I uploaded the next 2 parts already, in my post above you can see the links. Part 7 will come in a couple of days.

--

My personal Blog: www.onlyvintagewatches.com/blog

April 12, 2015 at 7:26 AM Flag Quote & Reply

Sir Alan
Member
Posts: 457

Video #6 has got me thinking :D

I need to dig out my 7T34 movements.......

I've also just bought a digital multimeter (model VC99).


April 13, 2015 at 7:04 AM Flag Quote & Reply

GeorgeClarkson
Member
Posts: 508

The 7T34 is very similar to the 7T32, as you already know, Simon. And actually almost 99% of the parts are interchangeable. glad that my video "got you thinking" ;) that was exactly the purpouse in making them. Video no.6 is the video almost everybody was waiting for, problably... :P

--

My personal Blog: www.onlyvintagewatches.com/blog

April 13, 2015 at 7:38 AM Flag Quote & Reply

GeorgeClarkson
Member
Posts: 508

Since video no.7 never made it to youtube, I am here to present the final result of the "rebuild" of the t732 )or Shiojiri Y182B) movement, inside a proper case.

I had bought a 7T32-7B30 NOS case with dial and hands, and what you see above is the final result. The only thing that is still "in the works", is the chronograph second hand, which is not original, but taken from a spare movement I had and it is slightly golden, not completely chrome as all the other hands of this model 7B30. I am looking for a proper replacement, but until then, it will have to do.

--

My personal Blog: www.onlyvintagewatches.com/blog

April 22, 2015 at 2:14 PM Flag Quote & Reply

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