Service: Seiko Diver’s Quartz Watch calibre 7546A

IMG_7142You thought you’d never see the day, but here it is. I’m servicing a Quartz watch ๐Ÿ˜‰

I got myself a proper quartz watch tester, as you have to be able to measure the average consumption, something you can’t do with a run-of-the-mill multimeter.

Not that I am a great fan of Quartz watches, but Seiko at least builds proper movements, and not the throw-away plastic trash that others put in their watches…

This watch was sent in by Torsten from Hong Kong, and it stops from time to time, and needs a service. I measure a power consumption of 2.9ย micro-amperesย  and that’s too much. Everything below 2.5 is fine, so there is too much dirt.


The wheel bridge actually has 2 jewels in it – that warms my heart a bit.


The gasket for the crown is almost completely dissolved – time to order a new one.IMG_7146

Bilingual day wheel.IMG_7151

For a quartz movement, this is as good a build quality as it gets.IMG_7155

Set and clutch lever assembly.IMG_7156

Bottom plate cleared.IMG_7157

On the top plate, I start by taking off the circuit board.IMG_7158

And here it is with its four screws.IMG_7159

This is a very sizeable motor coil indeed – no wonder the movement consumes over 2 micro-amperes.IMG_7162

With the gear bridge removed, you can see the wheels of the gear train.IMG_7168

Everything ready for the cleaning machine.IMG_7170

Reassembly starts off with the gear train.IMG_7171

I put the circuit back in, and test the movement. Power consumption is down to 2.1 micro-amperes, and I’m happy with that.IMG_7172

Now I can put the bottom plate back together.IMG_7173

The dial and hands go back on.IMG_7174

And I can case the movement.IMG_7175Back together and ticking.


12 thoughts on “Service: Seiko Diver’s Quartz Watch calibre 7546A

  1. Hi good article, could you tell me where you obtained the gasket set, and if it has a part number please. I currently have the same movement on my bench for a service..

  2. I do have a Seiko Quartz Sport 100 it stopped and i don’t get someone to repair it for me i think it need a new coil and i need help i’m from South Africa

  3. I do have a Seiko Quartz Sport 100 it stopped and i don’t get someone to repair it for me i think it need a new coil and i need help

  4. Surprised that ‘two jewels in the wheel bridge’ warmed your heart, as that tells me that despite having a 7548 circuit board, the movement in that watch is really a 7546, a 7548 has actually got three jewels in the wheel bridge….

  5. I know I should have paid more attention in GCSE Electronics but whats the copper capacitor\resistor for? I know some of the more expensive quartz watches have a sweeping movement on the seconds hand, is it anything to do with that?

    • If you are referring to the huge copper coil, that is the motor coil. It drives a little permanent magnet rotor, which drives the gear train to make the second hand move every second – so no sweeping second here. It’s the biggest mother of all motor coils that I’ve ever seen, so you have to be careful or the second hand will chop your finger off ๐Ÿ˜‰

    • Indeed! I still don’t like the price <-> build quality relation found in quartz watches. In the end, as with most watches, you pay for the case and bracelet, but that is just more pronounced in quartz watches.

      Nothing like taking apart a well built mechanical movement and admiring the build quality. Still waiting for that to happen with a quartz movement. This one is ok, but it doesn’t swipe me off my feet. Does Breguet do quartz movements? ๐Ÿ˜‰

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