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.
The different wave logo can be seen on the caseback as well as a production date of October 1978.
Once opened up things didn’t look too good with the discolouration around the battery area.
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!
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.
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.
With the calendar side stripped the extent of the staining can bee seen.
The circuit and coil were removed revealing a mess on the mainplate.
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.
This is how it comes out of the vinegar before the trip through the cleaning machine.
The watch was now fully stripped and went for cleaning and inspection.
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.
Reassembly started with the motion work, hacking lever and coil.
The circuit was fitted, the stem replaced and a new battery fitted, the movement then sprang into life once more.
The calendar side was rebuilt….
….and the dial and hands were refitted. Considering the rest of the damage these have survived in remarkably good condition.
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!
A new one was sourced and refitted.
And the crystal assembly was pressed back in.
The movement was recased and the watch lives again, considering what it’s been through it’s turned out beautifully!
The Watch Bloke 
Great job Duncan.
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Thank you, these models are often overlooked in favour of the true divers but I think they’re cracking little watches.
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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!
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The circuit, coil and crystal weren’t too difficult to source but the chapter ring was a lucky find!
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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
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Great Job 🙂 Just picked up a June 78 one of these up 🙂
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Amazing!
I bought this exact model in Singapore, 1979, and have worn it literally (almost) daily ever since. I last dived with it in 2002, in the Coral Sea, to a depth of 43 meters (unintentionally deep, on a drift dive).
It has only been “serviced” once, in 2001 in Bangkok, where I treated myself to a new Seiko as a Christmas present but found a very small timing discrepancy. I took both watches to the service department for comparison .. who had only to replace the O-ring, found nothing else needed, and admitted “it keeps better time than the new ones”.
It still keeps better time than all my new watches!
Doug Ross
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Hi, I still wear one of these purchased in 1982 which keeps wonderful time. It now could do with a professional check up and possible refurb. Are you still able to carry this out and source any necessary parts, including the bracelet.
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Hi John, send me an email to thewatchbloke@gmail.com to discuss your requirements please.
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Hi, did that but my email has been bounced back address unavailable!
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Apologies, I had gmail spelled as gamil! Try again now and it should get through.
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Any idea where I can get a replacement movement and crystal for this model?
I have one that I bought in 1976 that I would like to get working again.
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I got one of these watches for a Christmas present in 1980 from my wife. I still cherish it, it keeps brilliant time and the stainless steels used in its construction are very tough, it’s had a few knocks. In the mid 1990s I sent it to Seiko factory for servicing and it came back with the second hand pointer tip bent ( very slightly). Under the crystal is slightly misted as well. I was thinking of e-mailing you for a service and refurbish quote. Many thanks for your article.
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Thanks for this article. I have the same I bought late 1978. It has run ever since, though lately it’s running slow (it has a fresh battery). I’m thinking of giving it a cleaning/lubrication but have only worked on mechanical movements. Do you mind sharing what oil(s) you used for lubrication?
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HP1300, HP500, Moebius 9010, Moebius 9501 and Seiko TSF-451.
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Thank you for the prompt reply! I think I can figure out where most of these get used, but not sure about the HP500/Moebius 9101. Can you let me know where that goes?
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