Seiko AGS vintage

This week for a change I feature a rather interesting Seiko quartz watch from the ’80’s.  The Seiko AGS or Automatic Generating System Model 7M22-6A40 gents dress watch first appeared in 1988 and was an early automatic quartz forerunner of what’s better known now as the “Kinetic” series.  It was first pioneered by Seiko in 1986 as AGM and further altered to AGS when this watch came out.

Early Seiko Automatic Generating System watch

This 1988 April version has a nice white dial with Roman numerals, black coated hour and minute hands with a central gold coloured seconds sweep.  A date window – black against white @6 completes the neat easily read dial and a good “Hardlex” crystal to the front.  The date features a quick set on the first click of the crown.  Finished in satin gold plate with matching gold coloured bracelet it looks very neat indeed.  The bracelet which is very smooth to wear can accommodate up to around a 7.75″ wrist.

Seiko AGS Dress Watch

This particular watch shown here was a brand new Old Stock model which has been in storage lying dormant for over 20 years, so is in absolute pristine as new condition.

So how does it work?

It works using a rotating pendulum rotor in similar fashion to the rotor in a mechanical automatic watch which is inside and attached to a larger gear which meshes with a very small pinion.  It operates on the wrist movement of the wearer and rotates via a 1/100 gearing pinion, transferring energy to a power-generator at high speed to produce an electrical current and charges a capacitor (KESU) which in turn feeds the time circuits.  Being one of the earliest models with a 3029110 power capacitor the full charge may last about 3 days or 75 hours – the full charge takes about 800 swings of the rotor, so really has to be worn a lot to get the best capacity reserve out of it.  Another feature of this early model is that the second hand operates in 2 second jumps if the power reserve capacity drops to around 3 hours.  Now as it can takes quite a considerable wear time and wrist movement to build up a sufficient charge, it can sometimes seem as if 2 second jumps are normal!
All is not lost however as in 1990 owing to these older capacitors having faults they were replaced by the newer 3023 24R capacitor (KESU) module which really improved both the reliability and ostensibly allowed a whopping 90 days on full charge – much better – so the 2 second warning was not so evident.

This particular model features a 5 jewel all metal 7M22A movement which is actually very good quality and better than many modern quartz watches, which tend to have added plastic parts within them.

The dimension of this watch is very compact for an AGS or Kinetic watch and measures 40mm top  to bottom and side to side ( without crown ) just 35mm.  Thickness ( crystal to back cover ) is 9.5mm and with a 28mm diameter crystal.  Quite neat and unobtrusive as befits a dress watch and I have to say it looks very good on the wrist.

AGS 7M22A 5 jewel movement

In this image you can see both the rotor and the capacitor (looks like a battery) at the left.  The serial number follows the Seiko numbering system with first digit 8 denoting 1998 and the 4 for April.  The next 4 digits represent the model number in that month.  Quite useful to see such an unusual and Seiko historic movement mechanism and note the cal. number etc.  You can also hear the rotor operating though once against the wrist it’s almost inaudible.

So an unusual model and actually quite a milestone in watch terms.  This one is in fantastic condition even after just over 20 years since it first came out.

Cons – not really – but –
I suppose if I was honest the full charge capacity is a little low at 3 days or so and the 2 second jump could I suppose appear if you’re one of those that takes the watch off at night, or if you wear your watches in rotation and leave it in the watch display box for a month.
But that said it CAN be changed and upgraded very easily as I already have the newer replacement capacitor ready to fit – but confess I can’t be bothered replacing it – and it works fine anyway ‘cos I wear it 24/7 anyway.

Anyway not withstanding the above – it’s still an intriguing and to my mind a historically significant watch and a great addition to my collection.  So I’m very happy with it – it keeps great time and it will be with me for a long time I’m sure.

Addendum – February 2015

In the event I decided to change the capacitor for the replacement as it was obvious the watch was unable to keep a decent charge for more than a day or two at most.  Replacement is easy as the replacement 3023 24R is the same size diameter.

Note how the original capacitor "appears" smaller than the replacement.

Note how the original capacitor “appears” smaller than the replacement.

Don’t be fooled by the apparent size difference.  It is misleading when you look at the capacitor via the exhibition glass back as the visible top part of the capacitor appears smaller diameter than the replacement.  This is because the capacitor is stepped and the lower part is actually a larger diameter.  The old capacitor is usually the GC920 and can be directly replaced with the 3023 24R.
Remove the screw back of the watch, then unscrew the central Rotor screw and remove it.  This allows easier access. The capacitor is recessed and before you can take it out you have to unscrew two small screws holding the top plate surround.  Take the top plate away and underneath there is a small brown insulator gasket, simply lift it off from it’s locating points.

Note the top side of the capacitor has a smaller diameter than the bottom.

Note the top side of the capacitor has a smaller diameter than the bottom.

You can then remove the capacitor.

Fitting the new one is simply the reverse of the process and once all done up again, a few shakes of the watch and it springs into life – this time in one second ticks as it should do – a testament to the superior capacity function.  Once fully charged it should get at least 30 days and perhaps 60 days as the 90 days quoted may be over optimistic.

The original capacitor for the AGS.

The original capacitor for the AGS.

Interesting to note how this pioneering technology has moved on from 1986 and the amazing models that are now produced by Seiko and others.  Not only has the miniature generating system advanced, but the science behind battery and capacitor systems is almost unrecognizable today and prompted in no small part by the watch companies quest for miniaturization.  Indeed the introduction of “smart” technology has also hastened the quest for ever smaller and more efficient forms of energy production and storage.
We are entering the world of battery mediums composed of incredibly thin strips of material and now transmitted energy with no contact between storage and user.

Amazing times.

See the results of the change (after 1 week wear and 1 month in the display cabinet) – HERE (on 16th March 2015)


Categories: Spotlight, Watch reviews


8 replies

  1. I was looking for a watch for my wedding. I was originally looking at Tag Heuer and other swiss made watches but I fell in love with this Seiko watch the first time I saw it!

    The watch is very beautiful (or handsome I should say) and expensive looking. It also feels sturdy and strongly built. The features of this watch (ex: Kinetic technology) beats those of the more expensive ones. You get more than what you paid for in my opinion.

    • I probably agree SS, the watch has a certain quality of build appearance that looks just right and it also appears larger than it actually is. The AGS system works very well and spares are still available from both Seiko and third party suppliers which is a bonus. Thanks for your comment.

  2. Good day,
    My AGS no longer holds a charge, no mater how much kenitec energy is produced.
    Is the Capacitor dead, can that happen, and can it be replaced or repaired.
    Thanks in advance…

    William Davidson

    • In best condition as this one is – around £170 to £200 today (they are getting scarce) would be the top price.
      I’ve seen other AGS variations starting around £100, but as always, very dependent on condition.

  3. Sir: I have a Seiko AGS which looks just like yours except the face has marks where the hours are and the band is silver with gold on every other link. My watch is stainless except for the gold ring around the face. S/N 7N3553. I am looking to replace the capacitor as mine won’t hold a charge for more than a minute. Where may I buy one? Thanks – Bud Ingles – Wisc

    • Hi,
      My Post gives instruction how to replace the old GC920 accumulator.
      A simple Google search brings up the newer Seiko 3023 24P replacement on numerous sites, so sourcing one shouldn’t be a problem.
      The new one gives a much better power reserve and my Seiko is still going well.
      Hope this helps.

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