Seiko 2620A quartz technical manual

[DanB]

I'm working on a Seiko 2620A quartz movement from a watch dating back to about 1979. Any chance someone has the technical manual? I have what's called the "technical guide" that I got from the Mizeni.com site which is the same as the one from Cousins which are really just parts lists, but what I need is information on the order of the train of wheels when reinstalling (when I disassembled the watch they moved out of order so I wasn't able to get a good photograph of them for when I was putting it back together).

Thanks!

 

I figured out the train order. Now I just need to get the bridge back on - not so easy. Would still like to get a detailed tech guide if one exists.

[bklake]

There are technical guides for the 2628 and 2633.  I think the 2620 has no calendar side or seconds hand.  Between the two above, you should be able to work it out.  Take lots of pictures.

[JohnR725]

On 12/14/2022 at 10:04 AM, DanB said:

Seiko 2620A quartz movemen

It might help if we could see a picture of what were talking about.

The problem with the technical guides are there typically for parts lists is not necessarily for repairs. Not that the tech sheets didn't probably have repair section somebody just scanned in the parts list. Not unique to Seiko I've seen that with quite a few documents on the cousins website of only the parts list is shown not the technical

On 12/15/2022 at 12:51 PM, bklake said:

There are technical guides for the 2628 and 2633.

And yes if you go through the list of all ones after that they're basically all the parts list except these

On 12/14/2022 at 10:04 AM, DanB said:

Now I just need to get the bridge back on - not so easy.

This is the problem within a quartz watch or in a watch for that matter. It just takes a lot of patience. And maybe just some Luck

Seiko 2633A.pdf Seiko 2628A.pdf

[DanB]

Thanks again for the advice and tech guides. They were very helpful. The watch is reassembled and is working. Before starting I thought it was kaput, but the cleaning worked. Patience and persistence helped. 

I have one question - should I need to regulate it, which direction would the trimmer be turned? Intuitively it would go clockwise to speed the watch up - is that correct?

 

[JohnR725]

3 hours ago, DanB said:

I have one question - should I need to regulate it, which direction would the trimmer be turned? Intuitively it would go clockwise to speed the watch up - is that correct?

First off the amount of regulation by turning to trimmer is really really small. Usually the timing machines are measuring seconds per month so I not talking a lot of time change here. Then you will be really careful how you do this somebody else on the discussion group pressed a little too hard and broke their trimmer. On something that it cannot conveniently be replaced perhaps. Then the tremor is made out of ceramic and ESC it will break if you push down on it. Plus it has interesting property they can go in either direction. So while it might seem logical to turn in one direction conceivably going on the other direction would be the direction you have to go in. So unless you find it's off by seconds per month and it makes you unhappy I would just leave the tremor alone ideally should have a timing machine to see what's going on.

[DanB]

Thanks. I don't have any testing equipment for quartz, so I'll just have to check it on how it performs real time. Over the past 24 hours it seems fine, so I may not have to fuss with it, and if I do I'll proceed with caution.  Just grateful to have it running again. FWIW, my mother and I bought it for my father on his 60th birthday in 1979. He wore it on and off for a long time, passed away in 2000 and it has been sitting in a drawer ever since. 

[LittleWatchShop]

I agree with John...lea e it be. But to satisfy your curiosity,  the trimmer is two overlapping plates, each with a half moon of conductive material. When the two half moons completely overlap, you get maximum capacitance. Turning either left or right reduces the capacitance.   So, depending on the current orientation you may need to go right or left to, say, speed it up.

[bklake]

My limited experience with this era of Seiko movements is that they were well regulated from the factory.  Once cleaned and properly lubed, they run very close to how they left the factory.  One of my 7546 watches was running about 10 seconds a week slow.  Cleaned and serviced it is about 2 seconds off when I reset it twice a year for Daylight Savings Time. 

I tried to turn the adjustment screw on a 2625 once and it broke free from the circuit board.  It had a little battery leak corrosion but when something has not turned for 40 years, it doesn't always want to turn. 

Service it and take what you get.  It will probably be very close to perfect unless someone messed with it before you. 

[DanB]

I've taken everyone's suggestions, left the regulator as is, etc. It's been about a week and it's running quite accurately with a new crystal and gaskets. This was a great warm-up before I tackle my 7546-6049. Thanks again. 

[MichaelLLF]

I was Googling info about my 2620A and came accross this thread.  Here's another link I found that might be helpful.  

https://seikoserviceusa.com/uploads/datasheets/2620A.pdf