V Posted July 26, 2006 Report Share Posted July 26, 2006 I have received an Asian 21J Pam (the cheap one) and although it is keeping PERFECT time, the seconds hand is very bumpy and skips seconds on the area of 0-15 minutes (and sometimes till 30) On the other side of the seconds it runs smoothly... Also when I wind it and it reaches 0 then it skips seconds while I am winding. What do you think it might be? Quote Link to comment Share on other sites More sharing options...
Shasta Posted July 26, 2006 Report Share Posted July 26, 2006 Gear has uneven teeth Quote Link to comment Share on other sites More sharing options...
V Posted July 26, 2006 Author Report Share Posted July 26, 2006 Gear has uneven teeth But shouldn't it be all the time the same skipping and bumping? SOmetimes (very few) it runs smoother than others. If the problem is gear's uneven teeth is there any cure? Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted July 26, 2006 Report Share Posted July 26, 2006 Your problem is due to the design of the movement, it's an indirect center seconds drive (as are the Miyota and most Asian auto models). Indirect seconds is a big gear driving a small gear for the seconds, and these are known for having jumpy seconds display. It does not affect the timekeeping, is not a defect or anything that you can fix or correct...it is what it is... Here's how you test this out... Take your watch and hold it up with the "12" facing up and watch the seconds hand, especially from 12 - 6 as it moves...my guess is that it's jumpy from 12 to 6, but smooth from 6 - 12... Now turn the watch upside down, so the "6" is up and do the same test...I guess that now the seconds hand is jumpy from 6-12, and smooth from 12 - 6, the exact opposite of the problem with it's right side up... Why? Because gravity takes up the slack in the gears when it's going in the upper against gravity direction, but when it's going down towards gravity, the slack is not taken up in the gears... I wait to see the results of your test... RG Quote Link to comment Share on other sites More sharing options...
Usil Posted July 26, 2006 Report Share Posted July 26, 2006 Amazing, I just tried this on my PO and that is exactly what I saw. Looks wierd but as long as it keeps good time. Usil Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted July 26, 2006 Report Share Posted July 26, 2006 Amazing, I just tried this on my PO and that is exactly what I saw. Looks wierd but as long as it keeps good time. Usil You had your doubts?? RG Quote Link to comment Share on other sites More sharing options...
V Posted July 26, 2006 Author Report Share Posted July 26, 2006 You had your doubts?? RG WOW.. You are so right... It happened exactlly what you said Do you think there is a way it will improve in the future? I guess it is the desing of the movement but an Asian 21J I had on my Pam Submersible 24 it was much much smoother.... Josh told me that it may improve after a couple of weeks of wear? Quote Link to comment Share on other sites More sharing options...
RWG Technical Posted July 26, 2006 Report Share Posted July 26, 2006 WOW.. You are so right... It happened exactlly what you said Do you think there is a way it will improve in the future? I guess it is the desing of the movement but an Asian 21J I had on my Pam Submersible 24 it was much much smoother.... Probably not, it's a design issue, and time will not change the way it is... Most Asian models are close copies of the Miyota 8215, and are interchangeable... Replacing it with a Miyota is probably the only way you will fix it...but it's only astetics, it will work fine and keep good time...the one I have does... Quote Link to comment Share on other sites More sharing options...
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