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T5AUS

Seiko Chrono Sport

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Hi guys, newbie here with a question on this 7A38-6020 Sports 100 Chrono which I recently picked up in a junk shop. I stuck in a new battery and she is firing away perfectly although I am not sure what the top left Chrono button does, I thought perhaps a light but nothing happens when pressed and it moves quite freely. The other three are fine, top right being stop & start of chrono , bottom right the chrono reset and bottom left the day date set.

The crystal is gouged and I know from searching on here, replacements are a problem so something I have to work on.

Another little niggle is the inner hours/minutes chapter ring, it seems to be slightly off set if you line it up with say the top 12 and bezel marks, could it have come loose and need re setting?

Also, are there any download instruction manuals available for these anywhere ?

Thanks for any help

SeikoSport1001_zps79da7a46.jpg

SeikoSport1002_zps194bc24a.jpg

Edited by T5AUS

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SeikoSport1004_zpsa5152c35.jpg

Just a follow up, I took her apart today and realigned that chapter ring which I think has improved it although the main outer bezel, which I think is fixed, does not quite line up so I am going to have to remove the insert and move it a fraction anti clock wise.

Whilst I had the movement out the battery became dislodged and so now all chrono hands re set to the positions in the photo. I have removed and re attached the battery several times to try and get to reset correctly but they all just set to different positions around the dials ? Is there a magic default system to reset these to TDC ):

(hope I am asking these questions in the right forum, anybody out there?)

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To answer a couple of your questions, the top left pusher button is for split timing when the chronograph function is running. Press it once and it will freeze all the hands. Press it again (say after a few seconds) and the hands will advance to where they would have been, and continue timing as before.

To reset all the chrono' hands to zero (often needed after removing and replacing the battery), pull the crown out to the first position, and click the pusher buttons in turn: the 2 o'clock pusher advances the 1/10s subdial hand; the 4 o'clock pusher advances the center sweep second hand and the 10 o'clock pusher the 30 minute subdial.

Something else you might want to try, once you've got the hands all zero'd (or set to TDC as you put it) and the crown pushed fully home:

Press the 4 o'clock pusher and hold it in for a couple of seconds; all the chrono' hands should complete one revolution. This is the movement's inbuilt self test.

Looks like you got yourself a pretty decent example, though a lot of what was originally red printing (on the dial and bezel insert) has faded. It's a common problem.

You'll find plenty of information on these watches on the Seiko 7A38 forum. There is a topic specifically about your model:

http://www.seiko7a38...nodised-finish-

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Also, are there any download instruction manuals available for these anywhere ?

It's not the best of scanned copies, but here you go: http://thewatchsite.com/files/Seiko%20User%20Manuals/7A38%20-%20E.pdf

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Just a follow up, I took her apart today and realigned that chapter ring which I think has improved it although the main outer bezel, which I think is fixed, does not quite line up so I am going to have to remove the insert and move it a fraction anti clock wise.

A word of warning - Don't even think about it !!!

The bezel insert on a 7A38-6020 is acrylic and molded into the channel. It does not come out. I would recommend that you don't even try removing the bezel until you've found yourself a replacement crystal. These bezels are only held on by a rubber o-ring, but they are frequently reluctant to come off. If you twist them, in attempting to get them off, it is not uncommon for the acrylic insert to crack - usually right down the center of the lume pip triangle.

PS The bezel should rotate (both ways). Maybe yours is clogged up with dirt.

Edited by DeeDubya

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Thanks for your replies Deedubya, and apologies for my late response. I managed to pop the bezel, carefully starting with I fine Stanley knife blade and then a slightly thicker knife blade, just working at it gently around the bezel until it was freed. Then I gave the inside area a good scrub in warm water with an old tooth brush, worked a treat, there was a lot of gunk. When I came to put it back together I dropped a little watch oil around the inside of the bezel where the rubber ring sits and then pushed the bezel back down on it firmly until one side was down with the other side still a millimetre off and refusing to go further. I then placed a small piece of flat wood along the side that was still raised and gave it a firm tap with a hammer and it snapped on nicely. It now works perfectly

I did give the crystal a good going over with some fine diamond dust past and some fine wet & dry paper while the bezel was off which made a small difference so it doesn't look quite so bad but in the end, I think the only answer really is a new crystal. Are these crystals available, I heard somewhere that they are not, is this true ?

You mentioned that some of the red on my dial & bezel has faded but I can see no trace of this faded red? Normally on faded dials and bezels of other vintage watches it's possible to see traces of the original colour, it never totally fades, so looking at mine it seems just to have been a plainer colour all over with only the sub second and main second hands ever being red, could this be possible?

Thanks

Phil

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You mentioned that some of the red on my dial & bezel has faded but I can see no trace of this faded red? Normally on faded dials and bezels of other vintage watches it's possible to see traces of the original colour, it never totally fades, so looking at mine it seems just to have been a plainer colour all over with only the sub second and main second hands ever being red, could this be possible?

Usually the red pigments on Seiko dials (and sometimes hands) and particularly the 7A38-6020 fade to a sort of dull yellow colour.

Yours appears to have faded rather badly, but quite evenly to white. Bleached by sunlight, perhaps?

I've never seen another quite like it. This is how it would originally have looked.

571783d1323118856-wtb-seiko-7a38-6020-seiko-7a38-6020.jpg

Edited by DeeDubya

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Thanks, I understand what you are saying, but if that we're the case why have the hands not gone the same way ? Was red the only colour variant of these

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Compare the 'white' subdivision markings in your watch's 9 o'clock and 3 o'clock subdials with those of the 6 o'clock seconds subdial (which should be white). I can't explain why the hands haven't faded in a similar manner. As far as I'm aware, the stainless version of the 7A38-6020 only came with the black dial and (mostly) red markings. There is another brown PVD / black chrome version which has a very dark metallic brown dial with mostly orange printing. Those are usually more prone to fading to white - especially the bezel markings.

Edited by DeeDubya

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