Seiko 7546-6040

This Seiko Sports 7546-6040 recently came in for some refurbishment, it belonged to the current owners father and hadn’t run for many years. The Sports range of Seikos look like dive watches but are only resistant to 100m and carry a different logo on the caseback, a more stylised wave than the tsunami of the divers watches. This example was in need of a bit of TLC, the crystal needed replacing as well as getting it going again and servicing the movement.

Seiko 7564-6040

The different wave logo can be seen on the caseback as well as a production date of October 1978.

Seiko 7564-6040

Once opened up things didn’t look too good with the discolouration around the battery area.

Seiko 7564-6040

The caseback bore witness to where the battery had leaked years previously, this article should serve as a lesson in not leaving dead batteries in watches if you can help it!

Seiko 7564-6040

The date wheel has been discoloured by all the nasty vapours that escape when a cell leaks. You can see the periphery of the mainplate doesn’t look too healthy either.

Seiko 7564-6040

The calendar top plates are also stained by the battery, it gets everywhere as there’s no means of escape for all the noxious elements/gases that leak out.

Seiko 7564-6040

With the calendar side stripped the extent of the staining can bee seen.

Seiko 7564-6040

The circuit and coil were removed revealing a mess on the mainplate.

Seiko 7564-6040

Fully stripped it was going to need some attention before going into the cleaner. If you ever have a problem like this instead of trying to scrape the corrosion of with scrapers and fibrelass pens or whatever try putting it in a glass of white vinegar for 20 minutes or so. If you have an ultrasonic bath place the glass in that and give it a zap.

Seiko 7564-6040

This is how it comes out of the vinegar before the trip through the cleaning machine.

Seiko 7564-6040

The watch was now fully stripped and went for cleaning and inspection.

Seiko 7564-6040

Seiko 7564-6040

Another couple of victims of the leaking battery was the coil and circuit so a replacement set was sourced. On the damaged pair you can see the black corrosion on the underside of the trimmer and down the brass tracks. The coil’s wire was rotted through.

Seiko 7564-6040

Reassembly started with the motion work, hacking lever and coil.

Seiko 7564-6040

The circuit was fitted, the stem replaced and a new battery fitted, the movement then sprang into life once more.

Seiko 7564-6040

The calendar side was rebuilt….

Seiko 7564-6040

….and the dial and hands were refitted. Considering the rest of the damage these have survived in remarkably good condition.

Seiko 7564-6040

A new crystal was sourced and fitted. With this design of case the crystal is secured by a rubber gasket in the crystal ring and a black anodised inner ring pressed up from underneath. This assembly is then pressed into the case and held in place by a nylon ring, to remove it the chapter ring has to be pressed out which takes the crystal assembly with it. The problem with this method is the chapter ring generally gets covered in particles as it’s removed. When I used compressed air to remove these particles the battery gases had made the ink so soft that just blowing the chapter ring was enough to smudge it – another victim!

Seiko 7564-6040

A new one was sourced and refitted.

Seiko 7564-6040

And the crystal assembly was pressed back in.

Seiko 7564-6040

The movement was recased and the watch lives again, considering what it’s been through it’s turned out beautifully!

Seiko 7564-6040

Seiko 7564-6040

Seiko 7564-6040

6 comments

  1. Interesting watch and I want one!
    Really good job, Duncan. The clean up worked wonders on the movement. How easy was it to source those parts?

    Good read, thank you!

    Like

      1. Well I have one of these cracking watches. Bought in Jeddah in the early 80’s and worn continuously since then apart from battery changes and services at Seiko UK. It gains approximately 8 seconds in one week – not too shabby I think! Case back gasket (FH 2980 BOA) difficult to source…. I really enjoyed your post so many thanks

        Like

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