Seiko 6139A & 6139B technical service manual WARNING !!

[Endeavor]

I am certainly not the first one who happen to ruin the chronograph center-wheel of a Seiko 6139B.

The internet, when you search for it, is littered with stories, even here on WRT there are some.

One of the problems is that the service manual of the 6139A is readily available on the net, not so with the service manual of the 6139B. On top, reading other forums & stories, there are people who claim that there is hardly any difference between the 6139A and the 6139B movement, so the 6139A service manual will suffice.

However, one of the crucial differences is the design of the chronograph center-wheel.

Also the Seiko reference numbers are different. For the 6139A, the reference number for the chronograph center-wheel is 888610 and for the 6139B: 888612.

To lubricated the 6139A chronograph center-wheel, the following graphic picture in the 6139A service manual is given;

One has to press down the sprocket and oil it.

Unaware of the difference in chrono center-wheel design, I pressed down on the sprocket, but there was no movement. Perhaps not understanding or interpreting the drawing correctly, I pressed with the tweezers on the 4th wheel. This caused the 4th wheel, which turned out to be a press fit to the sprocket by the 6139B, to strip off the sprocket. Thereby me joining the line of all the others, who tried this before and are now searching for "how to fix" this misfortune.

In an older thread on WRT, member @ricardopalamino place a picture in which he shows the difference in center-wheel design between the 6139A and the 6139B. To the left the 6139B and to the right the 6139A.

As can be seen on the left center-wheel, the 4th wheel is pressed onto a sprocket. Pressing down on it, as shown in the 6139A service manual, gives a ruinous result.

People did several attempts to repair the damage, but so far, I haven't found a success story. Here is one of the attempts;

Reading what already has been tried, I tried a different approach ..... but sadly failed too.

Nevertheless, I'll show what I've done; perhaps somebody may fine-tune or expand on the idea and has success?

In my staking set was an anvil with a 4.5mm hole, exact the size needed to fit the chrono center-wheel "up-side-down". The distance between the clutch parts and the 4th wheel was 0.25mm. To support the 4th wheel as close as possible up to its center, I used feeler gauge blades, on one side a 0.25mm blade, and on the other side a combination of 0.15mm + 0.10mm blades.

This allowed me to tap the sprocket back onto the 4th wheel ......

The thickness of 0.25 blades doesn't prevent some "spring" action, and so my 4th wheel was slightly deformed.

The re-attachment seemed successful, but when trying to true the wheel, the connection failed again

Currently there is a NOS 6139B chronograph center-wheel on eBay. Last Sunday the price was €150, on Monday the seller increased the price to €165 !!

 

 

 

 

Prevention is better than the cure and I do hope that anyone in the future, searching for a 6139 manual, with read my "Warning".

As for my Seiko, I'm not going to invest €165 for one part and since the rest is pretty good, I will sell the watch for "parts or repair"

 

Edited April 17 by Endeavor

[watchweasol]

Hi as an addition a pertaining to the assembly of a 6319B  which will be handy for those working on this caliber

Polly's 6139 guide.pdf

6139A.pdf 6139B.pdf

[Endeavor]

25 minutes ago, watchweasol said:

Hi as an addition a pertaining to the assembly of a 6319B  which will be handy for those working on this caliber

The original 6139A manual is very clear in how to disassemble and how to assemble ...... step-by-step.

However I haven't seen the 3169B manual, even in the Japanese version around, which clearly highlights the difference in center-wheel.

 

6139A Seiko Technical Guide.pdf

6139_A.pdf

6139A.pdf

6139b.pdf

6139B repair guide jp.pdf

 

 

 

 

Edited April 16 by Endeavor

[nevenbekriev]

Nothing is lost at this stage. But You first have to take out the clutch part from the pinion. Then next is to fix the wheel table to the pinion. If it can not be riveted, then must be soldered. Then trueing, and clutch part reattaching. It is possible to make a bush that will stay press fitted between the table and the clutch and will hold tight the table in place instead soldering.

[CYCLOPS]

I saw one on eBay today in Canada for less and said it was NOS, that is one expensive part...

 

 

[Endeavor]

10 hours ago, CYCLOPS said:

in Canada

Perhaps not where you live, but here in DK, you get by the taxman financially quartered if you buy from outside the EUSR.

These center wheel weren't that expensive 5 - 7 years ago, around $45-$50.

I guess the stock is drying up and these days we have to pay with getting worth less & less confetti money.

Edited April 18 by Endeavor