Oscillating weight Seiko 7S26A

[Clicoon]

First post on this forum - first stripdown of 7S26A. When checking the position of the oscillating weight prior to removal, could not align it as explained in the Tech Guide for Cal.NH25/26. It seems to be cut-away such that I cannot match the centre of the weight with the winding stem while lining the tip of the weight with the balance bridge pin and the hole in first reduction wheel gear.

Started to wonder if my Tech Guide refers to a 7S26B? The watch I wear has a 7S26B and the weight looks more like the one in the Tech Guide ie; not as cut-away. Have attached a pic of the weight removed from from the stripdown job. Is the setting position as described in my Tech Guide the same for all 7S26 calibres? 

Have also attached a pic of the dial holding spacer showing some glue (goo) which I presume was used to hold the date dial flat. Would this have been necessary?

Cheers

 

[WileyDave]

1 hour ago, Clicoon said:

Have also attached a pic of the dial holding spacer showing some glue (goo) which I presume was used to hold the date dial flat. Would this have been necessary?

May have been used to hold the main dial flat , I have see this "fix" with broken/loose dial legs. Date dial should move freely inside spacer, glue wouldn't help it move. Did main dial come off with a fight?

[Clicoon]

Sorry - obviously should have said main dial. Only 2 brass coloured pins on back of dial and plenty of spots of glue. All came away without any effort. 

Thanks.

[WileyDave]

8 hours ago, Clicoon said:

Sorry - obviously should have said main dial. Only 2 brass coloured pins on back of dial and plenty of spots of glue. All came away without any effort. 

Thanks.

Can't understand why would someone glue down dial unless there was issue with legs or dial screws, the two pins on back seems correct, hope you don't find any problems when you reassemble. Good luck.

[jdm]

1 hour ago, WileyDave said:

Can't understand why would someone glue down dial unless there was issue with legs or dial screws, the two pins on back seems correct, hope you don't find any problems when you reassemble. Good luck.

I see a lot of glue on Seikos from the Philippines. The OP can tell where this one comes from.

[dadistic]

I've attached the 7S26A technical guide. The alignment method is on page 6.

 

7S26A_7S36A.pdf

[Clicoon]

Thanks dadistic - the Tech Guide I'm using for Cals NH25/26 was mentioned as "typical" for 7S26 Cals. but size and alignment of oscillating weight is obviously different between A-B-C cals. Thanks to your link to the actual Seiko 7S26A Guide I will proceed with more confidence.

As to the dial, I thought there would be more than two brass pins for it to sit level but no sign of any missing. The two pins I see,  only protrude a small amount, in fact the spots of glue securing the dial markers protrude nearly as much as these two pins. Can therefore see why glue may have been necessary, but hope I can install without the need for it.

Once again thanks to those guiding me on my way.

 

[jdm]

Thanks dadistic - the Tech Guide I'm using for Cals NH25/26 was mentioned as "typical" for 7S26 Cals. but size and alignment of oscillating weight is obviously different between A-B-C cals. 

No, it is not. Only the writing changes.

[dadistic]

The NH25/26 guide shows a differently shaped rotor. The rotors in the 7S26A and 7S26C Tech Guides are the same. I don't have a B, I don't know if one exists. 

Edited November 17, 2016 by dadistic

[jdm]

The NH25/26 guide shows a differently shaped rotor. The rotors in the 7S26A and 7S26C Tech Guides are the same. I don't have a B, I don't know if one exists. 

The shape if the rotor doesn't matter. The rotor must be aligned with its center line at 3 as the red circle in the illustration shows. This the position in which the magic lever is most efficient when walking, using the pendolum movement of the arm.

[dadistic]

15 hours ago, jdm said:

The shape if the rotor doesn't matter. The rotor must be aligned with its center line at 3 as the red circle in the illustration shows. This the position in which the magic lever is most efficient when walking, using the pendolum movement of the arm.

Correct. But the illustrated procedure is different, and can be confusing for someone who is not familiar with the movement. 

[jdm]

Correct. But the illustrated procedure is different, and can be confusing for someone who is not familiar with the movement. 

I think one should always try to fully understand what a tecnical manual tries to convey. Fortunately in this case it's easy as the illustration shows how the rotor must be dead on lined at 3H.

[Clicoon]

Thanks to all for the additional comment.

Now that I'm following the actual 7S26A tech guide the prior glitches are less likely. It will be some time before I get to reinstalling the rotor as I'm now at the early stage of reassembly and finding it a bit more difficult than the strip down. Much practice needed to reinsert small screws etc. Trying to assess the degree of wear on parts will also be problematic for me the novice. More study needed!

Cheers   

[anilv]

Don't think it needs to be exact. The idea is to have the rotor hanging at its optimum position for winding.. which is crown down (ie when you're walking and swinging your arms) and having the winding pinion in the middle of its travel.

Now I haven't gone thru all the Seiko literature but I don't think that there is any different setting for watches which don't have the crown at 3 o'clock (quite a few have the crown at 3:40ish). We are talking a radial displacement of 1/15 or close to 30 degrees here so I say get it as near as possible and be happy.

Anil

 

[Watchtime]

Where was the watch purchased? Sounds like a possible Mumbay Seiko or from the Philippines...use of glue is very common there....

If you post an image from the back of the mvt, you can determine what mvt is used, the rotor can be replaced by one not fitting the mvt.

[dadistic]

12 hours ago, Clicoon said:

Much practice needed to reinsert small screws etc. Trying to assess the degree of wear on parts will also be problematic for me the novice. More study needed!

When I did my first 7S26, I took the bridge on and off  ten times in a row as practice. Helped a lot.

[Clicoon]

Yes dadistic - that's exactly what I am doing at present. Need a steadying sip of something between each attempt !

[ro63rto]

Yes dadistic - that's exactly what I am doing at present. Need a steadying sip of something between each attempt !

You'll soon find that affects your ability to see [emoji23]

[Clicoon]

And keep steady??