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Seiko Kinetic Crystal


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Hi all!

I just picked up a lovely little Seiko Kinetic for $45 CAD. Just needs a new capacitor and crystal. I've already sourced and ordered the capacitor, but I'm having some trouble finding a crystal. I'd like to go with a genuine Seiko crystal if at all possible. If that's not possible, I'll just pop it out, measure it, and order a generic crystal. But before I do that, can anyone help me find a genuine Seiko part? The model of the watch is 5M42-0A30.

 

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20 hours ago, Dumasdrew said:

I'll just pop it out, measure it, and order a generic crystal. 

That is the most practical and economical approach. You can also fit a sapphire crystal for about the same cost of an original one, if you even were to find it.

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It should be 290A02SN02.  From that number we can tell it's Ø29.0 mm, glued in, sapphire, no-coating, and transparent.  Can't tell how thick it is unless there was a list that said how thick serial number "02" was for this crystal.

You don't need to remove the crystal to measure the thickness, which will be harder to get back in because it's doesn't look like it's press fit with a gasket.  Just put something inside the case that sticks out enough so that you can get calipers on the crystal and whatever is in there.  Maybe a plastic bottle cap?

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On 2/8/2021 at 9:59 PM, xyzzy said:

It should be 290A02SN02.  From that number we can tell it's Ø29.0 mm, glued in, sapphire, no-coating, and transparent. 

A bit strange is the OP wanting to replace it, which suggest it is badly scratched, that shouldn't happen with sapphire. Just like any other modern Seiko, it uses a nylon gasket, P/N 86580100.

Anyway as it happens in these cases of "in search of Seiko crystal" is always good to openly tell how this information is gathered, whicj is hardly a secret.

Parts numbers for a given reference can be found from a variety of online sources like the ones mentioned by watchweasol above, plus Boley.de and Seiko Australia. Of course, the fact that a part is listed doesn't mean that is available, or convenient to buy.

And here attached the Seiko document that allows to decode, to an extent, crystal codes.

Crystal Codes.pdf

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Thanks all!

The crystal is scratched and chipped, particularly over the date window.  I've attached a photo here so you can see. I agree that it's a bit odd that a sapphire crystal is in such a state, but as I've only just bought the watch, I have no insight into its history. Perhaps a previous owner had the original crystal replaced with something other than sapphire. I can live with it as it is, but for the cost of replacing a crystal I'd love to have a new one.

I'm 99.9% certain that JDM is correct and it is fitted with a nylon gasket. But I'll know that for sure once I pop it out. My measurements came out to 29.0mm, but I just wanted to make sure by cross-referencing an original part number. I'm always a bit skeptical of nice, round numbers. ?

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The fourth digit of "A" should indicate a glued in or non-water-resistant crystal.  A "W" or a "P" would be with a gasket.  At least, according to the decoding information in that Seiko newsletter.  The crystals I've personally seen and recorded haven't contradicted it yet.

You can also tell by the case construction mark.  This is the two digital code like "A1" that is inside a box, usually after the case model, e.g. "5M42-0A30 [R1]".  If the code is "Rn" or P, then it's a glued in crystal, while an "An" code would be pressed in.

A quick search brought up a 5M42-0A30 on ebay with a good view of the case back.  It quite clearly says sapphire, water resistant with NO pressure rating, and case construction type "R1".  I don't have any specs on "R1" specifically, but the other "R1" watch I've disassembled had a glued in crystal when I got it.

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