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Discussion Starter #1
Hi all,
another rookie issue I 'm trying to sort out. I have put together 2x 6139Bs and 1x A. I have 2 others I need to assembly and I thought they were one of each. But both train brigdes I have look like Bs ,one has a small fitting missing on the pusher lever, green on photo.This part isn't on the A bridge. It has a little nipple on the pusher lever it hooks onto. The A I have in the picture is up and running ,just waiting for the top pusher spring from.Japan. Its different to the one on the Bs which has the longer tail.
So on #2 & 3 marked with red circles are 2 different small bridges. The 2 black arrows point to different hole type.
Do you think 2 & 3 are from a B movement with slightly different parts. I think so ,but just having one missing apart (green).
I have mixed and matched parts to get 4 out of five going and looking to source parts I used as donors to get the last one up, but unsure what to do go forward with these two.
I hope I've explained myself enough to make sense.
Thanks for viewing Cheers Tony
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Tony - Based on my limited knowledge of these movements I would say upper train bridge 2 is from an A cal movement and 3 is from a B cal movement. The primary differentiators I have observed are the jewel and pinion setups you have circled in green as well as the reset mechanisms that interact with the hammer. You are correct that #3 is missing a piece that is held in place with a pin that is staked on the back side. This piece is what interacts with the hammer when pushing the reset lever. On the A cal bridges #2, that whole reset lever mechanism can swing away from the bridge. On the B cal bridges #3, that reset lever is fixed with limited movement and will not swing away from the bridge.
 

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Discussion Starter #3
Thanks for the quick reply, it's midnight here right now. The bed awaits, I have a couple of more question but I'm agreeing with your call bridge wise. So goodnight from Brisbane. I will post later.
 

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What I can't understand is why the #2 an A movement has the piece that's missing from #3 B movement because I thought the 6139A was like #1 without this part.

Maybe someone did an upgrade? Interesting...because now you need the longer spring.....
 

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Item # 3 is a 6139B bridge and # 2 is a bridge for a 6139A. If your building a 6139B you need to stick with bridge # 3. Regards
 

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Discussion Starter #6
Gents thanks for the reply. I agree with you all. I think the #2 was confusing me with the pusher lever setup from a B. So as you say Merritt some one along the way has modded it and put the B setup on it. I've spare B springs so that's ok. Now to source a replacement B bridge for #3.
Thanks again for your input and comments.
Cheers Tony
 

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There are 4 different train wheel bridges used on 6139's. 17J "A" movement, 21J "A" movement, 17J "B" movement, and 21J "B" movement.
 

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Discussion Starter #8
Oh Ok thanks for that for that. Better check my jewel count. Does that info account for the different pusher levers on the 2 "A"s?
 

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Oh Ok thanks for that for that. Better check my jewel count. Does that info account for the different pusher levers on the 2 "A"s?
Bridge #1 is an "A". Bridge #2 + #3 are "B's"

Circled in red, #2 is an early "B" bridge and #3 is a late "B" bridge.
 

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There are 4 different train wheel bridges used on 6139's. 17J "A" movement, 21J "A" movement, 17J "B" movement, and 21J "B" movement.
Tom is absolutely correct. I should have looked closer at #2 bridge. It is an early B cal bridge. The A movement bridges use a small metal pin staked to the top of the second button flyback lever to engage the hammer where the B movement bridges use a more robust plate staked to the top of the second button flyback lever to engage the hammer. I have worked on early A movements were that small pin has come loose or completely fallen away from the flyback lever and floating around in the bottom of the movement. Likely the reason Seiko changed to a more robust design on the B cal movements.
 

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Discussion Starter #13
Thanks for all your input Guys, I will chase down another bridge as I don't have a staking set or the part to fix #3.
 
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