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Many years ago, indeed way back in February 2010, I contacted Orient Watch Co. Ltd., regarding their J39's, which I'd then just started collecting. They never really did provide much in the way of information and I'll always remember that classic sentence from their email, which I've quoted many times before:

We had several type of J39 chronograph models until 1990 year, but it is regret to say that we do not have such records in hand now.

However they did kindly provide me with a .pdf copy of the J3920 Technical Manual (or at least 2 pages of it), which I uploaded to the website, soon after it got started:

https://www.seiko7a38.com/J3920Techmanual.pdf

I've often wondered if there might be a few more pages to the document - say as compared to the equivalent Seiko 7A38A Technical Guide and Parts Catalogue.

April 12, 2019 at 4:16 AM

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Seiko7A38

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Posts: 14428

It seems there are. Yesterday, I was idly googling 'Orient J3920' (as you do) and stumbled across this search result, which I can't honestly say I'd noticed before. God only knows how I'd managed to miss it. :roll:

https://www.awci.com/member-center/technical-guides-references/orient/page/3/

AMERICAN WATCHMAKERS - CLOCKMAKERS INSTITUTE

Setting Service Standards and Educating the Horological Community

Scrolling down to the bottom of that page (3), I spotted this:

So naturally, I attempted to register on the AWCI website, so I could log in and view 'the full document'. Unfortunately, I didn't manage to get past the second page of the process, because the mandatory requirements of the address fields called for a US State / Province / ZIP code. :mad: As it transpired, my failure to register turned out to be somewhat fortuitous, because there is a $175 annual membership fee payable (which I wasn't aware of). I didn't really want to join the AWCI anyway. All I wanted was to view that one particular document - to see if was the same as I already had.

So I filled in the contact form, explaining what I was trying to achieve and also sent an email direct to info@ACWI.com. Almost immediately, I received a reply from their Membership Coordinator, a very helpful lady named Maureen. After a couple more exchanges, late yesterday evening, Maureen very kindly scanned the full document and emailed it to me as a .pdf.

April 12, 2019 at 4:38 AM

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Seiko7A38

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Posts: 14428

This morning, I uploaded it to the website, alongside the existing 2-page document:

https://www.seiko7a38.com/J3920TechManual-Full.pdf

It's dated August 1986. As you can see if you click on the link, as I'd suspected, the document does include pages numbered 1 and 2, which Orient Watch Co. Ltd. had emailed me back in Februrary 2010. But there's rather more to 'the full document'.

Not surprisingly, it's very similar in format to the Seiko Cal. 7A38A Technical Guide. The main difference is that there isn't a separate parts list. The Orient part numbers and descriptions are both shown on the exploded views on pages 3 through 6 and there is a separate table of their equivalent Day Wheels on page 8 ....

.... which incidentally is something that's missing from the Seiko 7A38A document.

Most of the J3920 movement component part numbers shown in the exploded views are in the same xxxx-J3920 format as the Day Wheels in the above table.

Naturally, one of the main reasons I was eager to learn the equivalent Orient part numbers, was in the vain hope of possibly finding available stock of some of the harder to find obsolete components - especially with the prices some sellers are asking for Seiko 7A38 parts nowadays. I haven't met with any success so far. I don't really expect to either. One of the oldest results returned by a google search on 'Orient J3920' (which I'd first seen many years ago), is this, from a German watch and jewellery wholesaler, Flume Technik:

http://www.flume.de/en/249352.html

One last thought, for now - it really begs the question why Seiko Epson Corp. went to the effort of allocating separate part numbers for the Orient J3920 version of the movement, when all that differs from the OEM Seiko 7A38A version is the Orient J3920 stamped anti-magnetic backplate (and the blank battery +ve plate).

April 12, 2019 at 5:33 AM

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Seiko7A38

Site Owner
Posts: 14428

Isn't it strange, how Google suddenly miraculously produces 'new' results, out of the blue, for a term that you search regularly. I know that if I'd ever seen this one before I certainly would have remembered it. So, this lunchtime, I was idly googling Orient J3920 (as you do), and what should come up in the results, but a listing on Spanish classified site, Todocoleccion.net for an original copy of that Orient J3920 Tech Manual - dating back to September 2012 !!