WS 19: Servicing a SEIKO Chronograph 6138

Foreword and Notice

This is not a 6138 service manual but a photo series about servicing a 6138 Chronograph movement. Do not think by looking at these pictures, you could simply go ahead and dismantle your 6139 or 6138. While some parts of the procedure are explained, others are not. Thus simply enjoy this as a complete strip-down of a 6138 and learn about its components. Servicing and adjusting a 6139/8 requires skills, one needs to know its parts and their functions, otherwise it would become an endless and frustrating puzzle.

Rob had always wanted one of these bigger case (ca. 41 mm diameter) SEIKO chronographs and suggested to shoot a photo series about the complete servicing and adjusting of such a movement. This one is going to be in his private collection. All the watch work had been done by Rob, I simply kept interrupting him when I "needed" a picture. Despite those frequent breaks, all went well and speedily. Rob knows this movement very well, he had serviced more then 10 of those recently and thus to him this was a walk in the park.

Reto Castellazzi, Bangkok, October 2004

Please respect our copyright. Do not use any of the pictures in this report  for any of your Sales activities. This is not only to protect our copyright, but also to protect future buyers. There are so many Franken 6138 movements out there, if you see one advertised using our pictures, simply run!
Of course you are invited to use these pictures for your personal information and for discussion watch forums. If you use the pictures, the copyright mark may not be removed and the picture not be altered in any way. But once more: NOT for sales forums and NOT for Ebay auctions. We will report abuse immediately.

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The Start

The Case Back removed

The Disassembly starts

First Surprise

Dial Side

The Rotor is removed

Automatic Winding removed

The Day and Date Disks

Dial Side: Day Date disks removed, chrono hour wheels removed

The big parts Basket filling up

Rob at work

The small Parts Basket

The ultrasonic "Bath"

After the Bath, rinsing in Methyl Alcohol

Laying the Parts out

First Batch of cleaned Parts

Adding the big Parts from the first Batch

View of the Chrono mechanism and Balance

The wrong and correct Wheel

Chrono plate and Balance removed

The big Balance Wheel

Now the Movement is completely disassembled

The vertical Clutch 

The vertical Clutch opened!

The Top and the Chronowheel axle

Column Wheel Comparison with Valjoux 72 (3 pictures)

All Parts
<<< End of the Disassembly

Start of the Assembly >>>


The Dial Side

The Chronograph parts are reassembled

Date Disk

On the Timing Machine Vibrograf 200

A look at the Movement from the Side

Close-up from Side

Replacing Hands

HOROTEC Hands Press

The Magic Lever

The Case and Movement and the Automatic Winding system

The Case Back
The Happy End