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I recently acquired a 1991 Seiko 7T32-7G20 from a New Old Stock collection. They were manufactured in 3 versions, black dial and bezel, black dial with silver bezel, dark blue radial sunburst dial with silver bezel, and silver radial sunburst with silver bezel.

The one I managed to get my hands on has the dark blue dial. The case and bracelet are in mint condition, the hands dial and crystal are mint.

It had never been serviced so expected it to not work correctly and also expected battery corrosion.

On opening the case I was pleasantly surprised to see no corrosion at all. But the stopwatch, minute sub dial and alarm were malfunctioning.

I took it apart and on close inspection of the circuit tracks there were a few areas of very slight corrosion, bridging some of the tracks and thus shorting areas of the circuit. I rectified this, it came up like new and passed tests.

After a thorough clean, lubrication and reassembly of the movement, all functions now work correctly.

I'm really chuffed. In this condition from the 1990's they're extremely rare. I think.

Here are some images and a video:

 

 

7G20-1.jpg.6b4b25f94dc9caf7b8a51f18461ff044.jpg

 

 

7G20-2.jpg.42c68f4d6e71a0d5388d07f03f6741ff.jpg

 

7G20-3.jpg.b0914a0272f61a9d2b55dc0923e46a4c.jpg

 

7G20-4.jpg.682a89828459313e18e81ac0ddde82ed.jpg

 

7G20-5.jpg.ace20ce5fa7eb333bafc486a0f5cdb7b.jpg

 

7G20-6.jpg.cb810353dec6f186b23ad0abbae3b3d3.jpg

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    • Even after thorough cleaning unfortunately the issue persists. I have made sure that all wheels are perfectly clean, no teeth are chipped, no gunk is left built up on them etc. yet the issue is not gone. When reassembling the movement I of course checked if the wheel train moves freely as that was the suspected cause of the issue before. And the intersting thing is - it does - but only in the "wrong" direction. Driving the wheeltrain by turning the mainspring barrel in the opposite direction as it would turn in normal operation, all wheels spin freely, and continue spinning for a few moments even after I stop providing power by hand. They behave the way I'm used to and have seen with other wheels before. However: When I apply torque in the opposite direction, the power delivery througout the train is not smooth or continuous. While it does turn, there are stages of increased resistance in the train. In addition to this, you can hear a slight "rubbing" sound whenever the trian passes by this point of increased resistance. The sound, to me, is more indicative of a surface rubbing on another surface, rather than the teeth of two wheels getting stuck within each other. Installing the click and putting a wind in the mainspring confirms this same issue, it does unwind and all wheels are powered, yet when the power reserve approaches depletion, it doesn't have enough power to push the wheeltrain past this point of friction. The slightest bump on any of the wheels will free the train, make it spin for however many rotations and then get stuck in the same way. You can do this several times before the power is actually completely depleted. This has really left me dumbfounded. I have inspected all of the wheels, pivots, teeth etc. on the entire wheel train and can't find any traces of dirt, any bent teeth or any warped or out of plane wheels. Besides: If one of the wheels was bent and rubbing up against some other part of the movement during a rotation, shouldn't it be doing this regardless of the direction of the rotation? This is supremely confusing to me and I can't figure out for the life of me why there is increased friction in only ONE direction and not the other. Installing the balance yielded the same result as before the disassembly: the watch runs great for about 50 seconds and then get's stuck when the wheel train get's bogged down. I mentioned earlier that there is a periodic scraping noise that can be heard when the gear train turns fast, this noise is not present when turning the train the opposiste direction. Does anyone have any ideas about which parts of the movement I can check for rubbing? I found no signs of wear or scraping on any of the bridges etc. so what would cause this periodic friction in one direction but not the other? I am very much a novice and have never dealt with such an issue before so I would love to hear what you people think about this. Thanks.
    • For me the second site has been hacked. 
    • https://www.mikrolisk.de/show.php?site=280&suchwort=Tschuy-Vogt&searchWhere=all#sucheMarker Wierd the first link didn't work.  They used other manufacturers movements, like most watch companies.  The watch you are asking about has this movement  https://calibercorner.com/ronda-caliber-3540-d/
    • Is there a way to interpret that?  I assume that is information on the watch?  Thanks!
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