Seiko SQ Sports 100 - how to service

[DanB]

Hi all, 

I bought this Seiko Sports 100 new in 1978 and over these 40+ years it has run incredibly well. It has had a working battery in it for probably 3/4 of those years so has almost been running continuously, though not worn nearly as much. The only thing wrong with it was the crystal which was full of scratches. I just changed it, as well as replaced the bezel gasket and case back gasket. I'm considering giving the movement a service, but my only experience is with mechanical watches. I searched for YouTubes about this particular model but could not find one.  Anyone have any advice on how I should move forward on this, where I might find more information? Thanks!

[Poljot]

40 minutes ago, DanB said:

Hi all, 

I bought this Seiko Sports 100 new in 1978 and over these 40+ years it has run incredibly well. It has had a working battery in it for probably 3/4 of those years so has almost been running continuously, though not worn nearly as much. The only thing wrong with it was the crystal which was full of scratches. I just changed it, as well as replaced the bezel gasket and case back gasket. I'm considering giving the movement a service, but my only experience is with mechanical watches. I searched for YouTubes about this particular model but could not find one.  Anyone have any advice on how I should move forward on this, where I might find more information? Thanks!

 

 

Probably here: download your parts list

https://www.cousinsuk.com/PDF/categories/3127_Seiko 7546A.pdf

[rodabod]

My personal opinion for quartz watches is that if it keeps good time and gives a good amount of life from each battery then leave it as-is. They do not suffer bearing and pivot wear like mechanical watches do. And some of the parts such as the hands tend to be flimsier and do not always handle repeated removal and refitting as well as more rugged parts. 
 

If you do need to clean it, then this is a simple caliber - the entire going-train is underneath the bridge with two screws holding it down. 

[Poljot]

41 minutes ago, rodabod said:

My personal opinion for quartz watches is that if it keeps good time and gives a good amount of life from each battery then leave it as-is.

I would only recommend changing the back cover gasket and crown wheel gasket / O-ring, and apply Seiko silicon grease to make sure your watch is water/air tight.

[DanB]

Hi Rodabod, Poljot,

Thanks for the Cousins info reference Poljot, and the followup re: gaskets/silicon grease. Rodabod, that's interesting advice. I was resistant to dive into a service, at first from the "if it ain't broke, don't fix it" perspective (I know that thinking doesn't apply to mechanical watches), but also because it has been remarkably accurate and reliable from the get-go. I typically get 6+ years per battery (I don't think the battery has been changed much more that 5 times in it's entire life), and it continues to keep running solidly. I may just wait until it doesn't run properly, and that will indicate it's time for a service (I'll probably need a service before then).

Re: how watertight it may still be, I will think of it as "water resistant", rather than as a watch that can be completely submersed. When I first got it (I was in my mid-20's), I did go swimming with it just as a lark. I've kept it intentionally out of the water since.

[MechanicMike]

try watchsleuth.com

I've used it a few times. it's helped.

[jdm]

8 hours ago, MechanicMike said:

try watchsleuth.com

I've used it a few times. it's helped.

That website is for identifying Seiko models but here the OP was asking about servicing his quartz watch.
I agree with the answers given above: no, unless there is any problem with it.

[JohnD]

I have it's brother......

Needed some TLC when obtained, rebuilt using the movement from a donor dress watch and fitted the day/date wheels from the diver, along with the dial and hands....

[Poljot]

1 hour ago, JohnD said:

I have it's brother......

Needed some TLC when obtained, rebuilt using the movement from a donor dress watch and fitted the day/date wheels from the diver, along with the dial and hands....

Well done! Someone asked me to replace battery in his "Seiko".. It was NOT Seiko inside, and both Hour & Minute hands were generic "cut to fit". Even plastic movement holder was also from another movement... What a chaos. I found a donor Seiko in questionable condition, but with original movement and hands, took it apart, cleaned, reassembled and, just like you, placed the old dial. Now it is perfectly legit Seiko!  

I also fixed "fake Seiko" Miyota and it is running (do not ask why i did that - just a habit, i guess).

[DanB]

Wow, JohnD, that movement looks like it took on quite a bit of water over the years. Thanks for sharing that. Great (and clever) that you were able to bring it back to life with the donor. There were so many of those quartz Seiko's made back in the day (probably millions?) that I bet there are a fair number just sitting in peoples chests of drawers.

 

[JohnD]

3 hours ago, DanB said:

Wow, JohnD, that movement looks like it took on quite a bit of water over the years. Thanks for sharing that. Great (and clever) that you were able to bring it back to life with the donor. There were so many of those quartz Seiko's made back in the day (probably millions?) that I bet there are a fair number just sitting in peoples chests of drawers.

 

The Seiko 7546 movement was the original quartz movement based on the 6309 automatic movement (the dial side of the movement being identical to the 6309 and sharing the same parts) and was 'refined' with one extra jewel in the bridge to creat the 7548 in the 7548-700* series of 150m quartz divers watches...

.Many of the early 7546 dress watches have been canabalised for their movements over the last few years,to replace movements in 7548 divers and up to a short time ago they were not seen as collectable. The supply is now drying up and they are now seen as collectible in their own right, with the price rising accordingly...Some of my favourites here, that were initially bought by me to be  donors but were reprieved and are now in my collection....

Edited December 6, 2020 by JohnD

[DanB]

Thanks for that information. Those watches look cool. I didn't think that much of them back in the 70's/80's, maybe because they were so ubiquitous. But I also don't think I paid that much attention, and now with my diver back on my wrist I have a renewed interest.  Those integrated bracelets on those watches you have look really good. 

[JohnD]

1 hour ago, DanB said:

Thanks for that information. Those watches look cool. I didn't think that much of them back in the 70's/80's, maybe because they were so ubiquitous. But I also don't think I paid that much attention, and now with my diver back on my wrist I have a renewed interest.  Those integrated bracelets on those watches you have look really good. 

Your 7546-6040 100m Sports 'Divers' watch is now very collectable and worth  more now than when you bought it in 1978 (even adjusting for inflation). try to keep the bezel insert in good condition, they are irreplacable, as far as I know an after market replacement has never been made for these and Seiko never sold the insert on it's own, only complete with bezel and those are now even rarer than rocking horse droppings......

[DanB]

That's good advice re: the bezel insert. I'm lucky it's in relatively good condition. I do have a question about the bezel gasket. My local watch parts distributor, Otto Frei, did not have an original replacement bezel gasket for this watch case, said it was discontinued, so I installed an O-ring gasket, 35mm inner diameter x .6mm width x .6mm thick. It kind of works, but not so great. Do you have any suggestions for the correct bezel insert?

[Bodo]

Personally I think overhauling a quartz is important. This is because I've seen worn bearings, over oiled calendar sides that spread to the day date wheels, rust forming, moisture or grease on the dial outer edge where it meets the chapter ring that can pull paint in future if worked on, worn centre wheel holes that may require jewelling, it helps battery life, it helps lower circuit consumption which may increase life span and is just a good thing to do to maintain these things even if not subjected to the same wear as an auto. There is still wear and good reason to check all is well, imo.

Edited December 6, 2020 by Bodo

[DanB]

Bodo, on a quartz movement like this would you suggest similar oil choices as one would use for a mechanical watch train and metal to metal friction points - D5/HP1300, 9010, grease for keyless works, etc?

[Bodo]

I tend to use 9504 for keyless, very small amount... also on centre wheel staff for canon pinion. 9010 or Moebius quartz oil on jewels and 9104 on bearings. 9010 on outside of cannon pinion for hour wheel and maybe a touch of 9104 on the date wheel jumper where it meets the teeth of the date wheel.