# Inside The Seiko 7546 Movement



## Sir Alan (Sep 10, 2010)

I've bought three Seiko 7548 watches, two working perfectly and the most recent (still in transit from the States) listed as not working.

So, in readiness to hopefully fix this one, I've also been collecting the sister movement to the 7548, the 7546.

From what I've read, most of the parts are interchangeable between the two movements.

Today I thought I'd have a good look inside one of the 7546 movements, this one was listed as:

"Scratched glass, not working. Havent got correct battery to test."

which I know from experience really means:

"this watch is dead as a dodo, you'll need a car battery to get this one going."

still, I do like a challenge, and any salvageable parts will be useful in the future. Here's what I found.



OK - obvious signs of battery leakage. Let's see how bad.



Hmmm. Pretty bad.



but there's limited damage to the circuit and tracks. Maybe the circuit still works?

Given there was a lot of debris in the whole movement, I decided to go for a full strip down and clean. Always a leap of faith the first time but I figured I've nothing to lose.





yep, definitely needed.


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## no8yogi (Oct 1, 2012)

I love these threads!! I am always impressed by your work!


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## Sir Alan (Sep 10, 2010)

Lifting the second bridge revealed the final part on this side of the movement. To remove this I needed to strip the dial side down.



so, time to flip it over and start on the dial side. There's more battery debris here as well.



the day dial comes off easily



as does the date dial.





this above picture was the most important one I took.


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## Sir Alan (Sep 10, 2010)

So, with all the parts removed (well, almost all - more on this later) this is what the main plate looked like:



and



I put some fresh solution in the ultrasonic cleaner and popped the main plate, the 3rd, 4th and 5th wheels and the two bridges in for a clean.

And here we go (I have re-fitted the center wheel and cannon pinion)





I then proceeded to reassemble the dial side, oiling as required.



that was the easy bit over with!!


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## wookie (Apr 27, 2009)

Hi

I enjoy tinkering with this caliber as the front is just a 6309 which I'm quite used to, all parts are interchangeable between the 7546 and the 7548 the only difference being one jewel and of course some 7546 watches are 3 o/clock crown position, I think most 7546 fixer uppers are now being bought up to help repair the 7548 as coils and circuits are all gone every where.

Fingers crossed for you that she will fire straight up once cleaned :yes:

wookie


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## Sir Alan (Sep 10, 2010)

The more complicated part was the setting mechanism. This took me a good couple of hours to suss out.

The first couple of parts went in easily:



and



but I couldn't figure out where, and more specifically how this part (the setting leaver) was placed.



I knew it went under those first two parts (the setting leaver spring and yoke), but couldn't figure out how.

I couldn't find any other tutorial on this movement or pictures, and the Seiko Technical Guide didn't make it clear either.

Luckily, after studying the photos I took when I was disassembling the movement, I worked out what was wrong.

I was missing a piece!!

Specifically the setting leaver axle:



apologies for the crud on this - luckily it was in the ultrasonic cleaner (in the mesh basket). I'm not sure where the black gunge has come from because from the strip down photos it was nice and shiny before its bath.

Anyway, I cleaned it up and popped it into the hole it had fallen out of. Then it was obvious how the setting leaver was positioned:


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## Sir Alan (Sep 10, 2010)

putting it together from here was fairly straightforward:





and then a test with the crown/stem in each of the three positions:







all appears to be working as it should.


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## Sir Alan (Sep 10, 2010)

Then the last few parts on this side. The date dial and guards, making sure to engage the finger spring:





and finally the day dial, again engaging the finger spring:



Tomorrow I'll do the other side and see if we can get this movement working .......


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## jonti (Mar 1, 2014)

What a great post, like a good book I cannot put it away & looking forward to "tomorrow".


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## Sir Alan (Sep 10, 2010)

Tomorrow arrived, and I skipped breakfast and went straight into tinker mode.

I studied the Technical Guide last night and noticed a couple of important points I'd need to follow.

So, here we go, starting with the rotor stator:



then the center wheel bridge



then the 3rd, 4th and 5th wheels and stator. I find that you just have to trust that these will find their bearing holes/jewels in the main plate if you carefully nudge them (I use a cocktail stick and sometimes brass tweezers):



all of the gear wheels including the stator were carefully cleaned:



then the crown/stem and clutch wheel:



the Technical Guide says to set this in the second click position before re-fitting the reset lever.



from here it starts to get fiddly....


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## Sir Alan (Sep 10, 2010)

The final part to fit was the plastic second setting lever:



then it was time to put the main bridge on:



this has to be done carefully and without any force, the bridge will initially float on one or more of the gear wheels that have not seated into their bearings (top and/or bottom):



The secret (which I learned from another tinkerer) is to fit the screws that will hold the bridge in place, but not to tighten them.

Then, guide each wheel in turn so that it finds its bearing hole, nudging and turning the wheels as necessary.

Then as a bearing sits in place, gently turn the bridge screws little by little, using the tweezers or cocktail stick.

This is a laborious process but again, you need to trust that everything does want to find its correct place and doesn't need to be forced. The result:



the main bridge correctly fitted - phew. I've also fitted the screw that holds the reset lever in place.

Next it's the coil and the +ve battery terminal:



and then the cleaned up circuit block - luckily none of the tracks have been damaged:



but will it work?


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## Sir Alan (Sep 10, 2010)

Nearly there .......

Here's the dial side:



and yes, having fitted the crown/stem and clutch assembly the quickset day/date functions correctly.

And the bottom side, with the dial holding screws fitted:



and we're almost at the moment of truth. We need one of these:



and I loosely fit the seconds hand (no dial):



as there is nothing to hold the battery in place, I have to pop the movement back into the case.

And ......................



it works. First time :thumbup:

I've really enjoyed this service. It had a few 'moments', the worst when I dropped the rotor while I was cleaning it with rodico and all I heard was the faint rattle as it fell on the floor and bounced off somewhere. Luckily I've learned not to panic and search methodically and very very carefully.

So, when my 7548 arrives I'll be ready for it.


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## dobra (Aug 20, 2009)

More, more!! Well photographed and described thanks.

Mike


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## chris.ph (Dec 29, 2011)

impressive :thumbup:


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## Caller. (Dec 8, 2013)

Very interesting - thanks!


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## ombray (Feb 14, 2014)

Wow great posts, keep them coming!


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## rdwiow (Aug 15, 2008)

Great presentation, they are a lovely movement to work on, when Seiko still made them really well.


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## Service Engineer (Dec 28, 2007)

Excellent work, as always. Superb pictures. Many thanks for taking the time to share your experience with this 7546. I've had a 7546 and currently wear a 7548 which I find an excellent replacement for my previous SKX007.


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## Thomasr (Oct 11, 2011)

wow i need to take more photos! I see you also opted for the 'carbon fibre' Bergeon movement holder, do you find the movements tend to ping out? I seem to not get on very well with mine


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## Sir Alan (Sep 10, 2010)

Thomas, I'd love to see photos of your work - I think it would be both interesting and very informative.

I have both movement holders but I prefer the carbon one - you're right, the movement can ping out but this reminds me to not over tighten the holder, and to be really careful how I position it around the movement.


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## Sir Alan (Sep 10, 2010)

I worked on another 7546 today, the 7546-8270

I bought this watch only for the movement, but when it arrived I realised it was just too nice to break up so today I gave it a spruce up and a new crystal (a Sternkreuz XMF 300.860).

When I put the crown back in, it didn't feel right, and when I went to pull it out to the 1st, the 2nd click position it came out completely. Hmmmm.

When I looked carefully I could see that the crown release button was stuck down. When I took the movement back out and looked more carefully i could see a sticky residue and a tiny fleck of rust around this area. From experience this was almost certainly from a previous battery leak.

I'm always amazed at the different ways battery leakage can move around and affect the internals of a watch.

So, given it was late afternoon and there was still good light I decided to clean things up properly. As ever I took a few photos along the way.

Here's a nice shot of the setting leaver axle:



and here's where it fits:



here's a couple of shots showing the day wheel and how the day jumper engages:





hands back on:



and the watch itself:


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## digibloke (Nov 26, 2007)

Great stuff. I'm amazed that you can do such a thorough job and take such ace pics at he same time. Top multi-tasking :thumbup:


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## mickyh7 (May 21, 2009)

Hope I'm not being rude, but after reading this post you sound like the person who could give my 7548 a new lease of life.

I'd love it to go for a few more years.

It took me ages to get it the way I wanted, but it's time it had a clean and service by someone who knows!

I've a post in 'tinkerers corner' right now, but no takers.

Thanks for taking the time to read.

Mick.


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