In spite of the numerous potential pitfalls involved in buying a classic Seiko automatic chronograph, I found myself bidding on another eBay auction, this time a black dialed 6139-6012 and winning it. The dial and handset looked mint, the case a little tatty with plenty of grime in evidence, but more problematically (and perhaps predictably), the movement was running very slow, and the chrono function was, more worryingly, out of synch with the rest of the watch. This latter problem is a sign of the common symptom in these watches of a slipping chronograph clutch with the result that the forward momentum of the second hand at each tick, causes the clutch to slip, impelling the hand forward more than it should, with the chrono then appearing to run faster than the watch. I had this same problem on the blue 6139-6005 described in an earlier post, and the watchmaker who serviced it for me (Richard Askham) solved the problem by replacing the chronograph centre wheel. You can see the clutch ring on this cross-section drawing taken from the service document for the 6139A:
With Richard no longer working on these movements (due to the shortage of parts), it looked like I had a paperweight on my hands. I did make enquiries with another recommended watchmaker in Bristol, but their estimate was well into three figures, and so that appeared to be that and at this point I shelved the project.
And then, a month later (July 2010) I spotted another 6012, this time a gold faced dial. I figured it might be worth a shot to see if the movement could be transplanted into the black dialed watch and so I bid, and won this one too, again for peanuts, and in due course it arrived. But luck was not on my side and the movement in this second watch was barely running at all. So, I now had two paperweights. Here they are:
At this point, the two watches assumed a rather forlorn position in my parts drawer, where I would encounter them from time to time over the following few months as I foraged for other parts. But slowly my courage gathered itself up and, with nothing whatsoever to lose, and everything to gain, I started to wonder how much more difficult could a 6139 be to service than a 6309, 6119 or 6106, all of which I had stripped and rebuilt on numerous occasions. The base calibre of the 6139 is, after all, a 6106. I decided to attempt a service of the movement fitted to the golden dialed watch because there was the possibility that the chrono centre wheel on this one was ok. I would then fit the black dial and handset assuming all went well. Cosmetically it also looked the cleaner of the two.
I started the process expecting it to be no more than a learning exercise, and to have a movement at the end that might run, assuming I could reassemble it, but not realistically expecting the chronograph to function correctly. So, we start, having removed the hands, with the top of the movement, auto-winder removed, revealing the pawl lever seat, the pawl lever and the transmission wheel, all part of the automatic winding mechanism:
With these parts removed we get a better view of the chronograph bridge which supports the hammer click (the mechanism that provides the resistance you experience in pressing the reset button) and which I’ve unhooked from the nipple on the hammer, and the minute recording jumper:
Next, we remove the chronograph bridge and get a good view of the minute recording wheel (the cog on the left), the intermediate minute recording wheel (next to it on the right) and the centre chronograph wheel (north north east from the intermediate wheel. To the left of that you can see the reset hammer that snaps the second hand and minute recording hand back to their zeroed positions when you push the reset button:
With the coupling lever spring (top above) and hammer spring (left above) and hammer all removed we see the two coupling levers whose job it is to lift the clutch ring off the fourth wheel when the chronograph is stopped (see diagram above). When it restarts (by pressing the upper chrono button) the clutch ring is released and is pushed down onto the fourth wheel by the clutch spring. The slippage I was experiencing with the black dialed watch may have been due either to a weak spring, or perhaps to clutch slippage due to muckyneddy on the clutch surfaces and/or fourth wheel.
Now, with the minute recording and intermediate wheels, plus the levers removed, we have a better view of the chronograph wheel. You can see here the chronograph finger curving round at the bottom of the wheel whose job it is to transmit the instruction to the minute wheel to turn one click, once per revolution of the chronograph centre wheel. For this to work properly the chronograph finger has to be properly aligned with the teeth on the intermediate minute wheel.
Here’s the chrono wheel out of the watch:
With the barrel, chrono wheel, balance and centre wheel bridge removed we have just the pallet cock, fork and staff and escape wheel to go
Here are all the bits and pieces
which contains ammoniated watchmaker’s cleaning solution. While that’s doing its thing, we can turn our attention to the case
which needs a jolly good clean, as you can see here:
After the toothbrush, toothpaste and if memory recalls a go in the ultrasonic bath it is looking a bit better
With internal bezel, bezel ring, crystal gasket back in place
the case is ready to receive its lovely new crystal, courtesy of Sternkreuz via Cousins
A nice view of the internal dome here:
and we hit a snag. I cannot get the bezel to seat properly, no matter how much force I exert with the crystal press. In the end I realise the problem lies with the crystal. It is too deep and the bevel is fouling on the inner diameter of the bezel. I fitted one of these to the 6005 discussed earlier without any such problems but had heard from others that sometimes they don’t fit. The solution required simply sanding down the bottom edge of the crystal until it fouled no more.
With the movement bits clean and shiny, the movement reassembly and oiling proved reasonably straightforward, with the exception of one issue that I’ll get to in a moment.
With the hands test fitted, the problem that revealed itself was that neither second nor minute register hands were resetting properly. Perusal of the service sheet for the 6139A does not offer much comfort to an amateur such as myself, suggesting polishing the setting surfaces of the hammer to get it to contact properly with the minute and second hearts, located respectively on the minute register wheel and chronograph centre wheel. However, this is not a 6139A but a 6139B, and those clever chaps at Seiko had installed an eccentric screw to allow you to change the balance between the two registers. You can see it in the photo above just below the pillar wheel. I suspect that at some point in the disassembly process, I had tampered with said screw upsetting the balance between the two registers. A 180 degree turn was all that was required to effect a cure. You will note also in this photo that the minute register wheel has changed colour as has the hammer. This is because in attempting to find a diagnosis for the problem I substituted these two components from the other watch.
In this shot, I am depressing the reset button which impels the hammer to impact upon the two hearts, resetting the two registers.
A close-up of the chronograph bridge shows the chrono finger and minute recording jumper correctly seated in relation to the teeth on the intermediate wheel and minute wheel respectively.
You can get an idea of what is involved in setting this up properly from the following
I hasten to add that it all simply worked when I reassembled the movement – no adjustment required on my part, which is just as well.
At this point, we are ready to pop the hands back on, having swapped the dials between the two movements. First, on with the hour hand, the movement temporarily housed in the other (uncleaned) case:
and then the minute register hand
At this point another hurdle. The red second hand originally fitted to the black dialed watch is effectively dedicated to the chronograph wheel fitted to that movement, but we have swapped movements. Fitting the hand to the replacement movement resulted in it being misaligned when zeroed. This happens because the shaft on which the hand is seated on the chrono wheel, is profiled thus
to prevent slippage when zeroing. And there is no guarantee that the shaft will be oriented in the same way on every movement. So a new chrono wheel requires either a new hand or for the old impression to be filed out from the inside of the tube with a cutting broach – something which can often still leave the hand insufficiently well secured. Unable to source a replacement hand of the correct colour, I resolved to paint the yellow hand originally fitted to the gold faced watch
As it had originally been mated with the chrono wheel now fitted to the black faced watch, it should align correctly when zeroed. After much experimentation, the correct colour and consistency of paint was obtained by mixing some red railway modellers emulsion,
with some GlasArt blue transparent paint, to get the correct brownish tinge to the red colour, all thinned out using lighter fluid. The resulting finish is excellent and the colour match almost spot on. The hand re-seated without further trouble (remembering to depress the reset button when fitting). Next up, remove the gaskets from the crown and pushers
fit new, greased gaskets (fiddly as hell)
and we are on the home straight.
Those of you fed up with every watch ending up on the ubiquitous NATO strap might hanker after a bit of steel. These watches would originally have been fitted with a bracelet such as these:
Mine came with one, in slightly tired condition, but a bit of elbow grease soon had it looking decent once more:
In spite of its ordeal, in the week following its reconstruction, it gained a total of 12 seconds. Not bad I reckon.
Post script: For more on this 6139 see here.
I am now restoring a 6139 6005 and I am facing the same issue about the second hand. It was originally dark red, but it was losing the color, the paint comes off in pieces. So I decided to clean it completely using I removed the paint with sandpaper and painted with acrylic paint. However, the first try is not satisfactory, with the lens the paint looks grainy, maybe I have to dilute the paint more?
do you have any suggestion?
Did you use a paint with glossy or matte finish?
thanks in advance
manea catalin said:
I was surfing the net in searching for instructions to disasemble 6139B movement and I landed here. I have a Seiko Chronograph 6139-8030 watch whith the minute hand of the chronograph that was off the axel. I manager to put it back , but now I don’t know how to put back the crown shaft. It is not kept in and is going out when I pull it. I think that the small button that you have to push to get the crown out is stuck in too deep and it can not catch the crown shaft now. Do you have a solution for that?
If the stem release button is not flush with the mainplate, then it may well be stuck in, preventing you from correctly installing the stem. You could try to release it with a bit of gentle probing from within the stem hole in the mainplate but if that does not work then I am afraid that the only solution is to remove the dial and hands and re-set the keyless works. Good luck!
manea catalin said:
I tried that from within the stem hole with no succes. I will take the dial out and try from that side too. Thank you , Martin, for your prompt response! Keep up the good work!
Hi, love your site, great work! I have picked up a rather well kept Pogue but I guess because it has sat in a drawer for 30+ years with the chrono engaged it will no longer disengage. If I stop the chrono the movement stops too. Does it sound like something I can free up without actually replacing the centre chrono wheel? It resets fine and keeps good time and movement is clean and nice looking. No signs of any moisture at all.
But if replacing the centre chrono wheel I can expect alignment issues when using the original sweep hand? Can it not just be moved to zero while depressing the reset button according to the hand setting procedures of the manual? Forgive me for my ignorance, I am far away from understanding the whole movement! But I was of the understanding that second and minute hands that don’t return to zero can be adjusted to do so simply by pressing the reset button and moving the hands to zero with a pair of tweezers? With this belief I went ahead and ordered one of the 3D printed holders from Vintage time Australia. Maybe I’m in for a disappointment… 🙂
With reference to the previous comment the stem release button also sits low on mine. It still works though.
Hope you can enlighten me with a short reply! Thanks!
The stopping problem is most likely caused by a dirty chrono centre wheel axle causing drag on the movement which then causes it to stop. Regardless of whether or not the chrono is running, the chrono (fourth) wheel forms part of the going train and is always turning. When the chrono is started, the two levers either side of the clutch spring move out, releasing the clutch plate which makes contact with the fourth wheel and the seconds hand then rotates. When you stop the chrono, the pair of levers move inboard, pulling the clutch plate away from the fourth wheel and the seconds hand then stops. In that state the fourth wheel still turns but it is no longer connected to the seconds hand pinion. If the lubrication on the centre chrono axle has dried out or become dirty, the axle can no longer turn freely and may then stop the movement.
So, what does this mean for your movement? Well, a proper service probably won’t do any harm but that presumes that the problem with the chrono wheel can be resolved by a clean followed by correct lubrication of the axle.
If it turns out you need a new chrono wheel, then you will almost certainly need a new seconds hand too. The chrono pinion has a profile cut into its end. When a new seconds hand is fitted, that profile imprints itself on the inside of the seconds hand tube and the two then form a pair for life.
Not such a short reply, but then it was a rather long question!
Hi Martin, nice job on the restoration! I’m hoping to restore a 6139B myself and like the gold and black 6012 design. Do you still have the spare gold and black 6012 by any chance, and would you consider selling it? I believe you have my email address if you are interested. Thanks, Joseph.
As it happens, I do still have that watch but it is probably not entirely complete. I will need to check but the movement may have offered up some of its parts as spares and I know that it needs a new chrono wheel. I’ll need to check the status of the hands too. If your email address is the one listed on your blog, then I’ll use that to confirm what’s what this evening.
Great, looking forward to hearing from you.
Bravo! Excellent read. I’m still working up my courage to work on my Citizen 8110a project but I might follow your advice and start on it!
Keith Robinson said:
Great information Martin. Thanks. When I got my gold faced Pogue recently (albeit a 6139 of the 6001 variety), I was amazed at the excellent +few-seconds-a-day timekeeping. But I then discovered that the chrono’ is running very fast – about 2 sec per 60! Your explanation of the probable cause of this is fascinating. However, as I have other chrono’s when needing one, I shall leave well enough alone and just enjoy the looks and time-of-day accuracy of this lovely watch.
I’m pleased to hear you enjoyed the post and found it useful. These are great watches.
João Silva Nunes said:
I’m looking for a 6139-6012 blue dial movement for my Seiko.
Does anyone have it for sale?
Bimal Charan Pati said:
Very well described. Do u have manufacturing drawings of every component of this movement. I am interested to study.
There are service manuals and illustrated parts lists online. Just do a search for 6139 technical manual and your should find the files.
Just got a mint 1973 6139-6012 with champagne silver face, no ’70M resist’ text cluttering up the dial, and the alternate language to English is Arabic!
I think most of the 6139’s bound for Asia or Middle East had the champagne silver faces.