I serviced a Pepsi variant of one of these a while ago.

This one is the plain black bezel version. It's been well used, but not abused. Although the crystal has seen some welding I suspect.



Caseback is nice and clean and no evidence of Edward Scissorhands doing any tinkering.



After the usual check and a brush down to remove crud, the caseback was removed and the battery taken out.



Then the hands could be aligned and removed.



With the hands off and safely stored the dial is removed, exposing the day/date wheels which come off next.



Beneath the day/date wheels are all of the dial side parts which are removed without and problems noted.



With all the bits put away, it's flip the movement over to do the working side. Here I've removed the train bridge, exposing the step rotor and the wheels.



The step rotor has been removed and captured in its own plastic container (it's a very powerful mini-magnet!). Similarly, the circuit assembly and coil block are removed and put into safe containers.



With the last of the movement parts out and safely stowed, it's time for the case. No dramas and everything is now ready for cleaning.



And does it need some cleaning!



More to come.

 

The case wasn't the only cruddy item.

Bezel ring



But after some elbow grease and some ultrasonic agitation, I think it turned out quite well.



As did the case with the same scrub-a-dub-dub and bzzzzzzzzzzzzzzzzzzzzzzzzzzz.

 

Last little bits for today.

With all the case parts cleaned and checked, it was time to drop in the chapter ring, seal ring, crystal seal and press in a new crystal.



Then the bezel ring was pressed on.



That's it for today. I'll take this grungy bezel and let it soak in a weak solution of water/dish liquid overnight and use a soft brush and pegwood to clean it up tomorrow.



And now I think it's time for a beer before dinner.

 

Well, nothing for ten days!


Been a bit busy though, getting a car ready to transport interstate for my Grandson's birthday present.
I wasn't totally slack though. The bezel was let to soak and then cleaned with pegwood and a soft toothprush, then it received its new seal (properly lubricated) and the bezel was pressed on.



Last step for the case was to clean/inspect/lubricate/install the crown/stem assembly. I'm glad I had my little crown tool to help with that.



The case was then completed by fitting a new caseback seal to the case so it would be ready for a basic waterproof test.

 

With the case out of the way, I had time to turn my attention to the movement parts.



The main plate/wheels/setting parts etc were "ultrasoniced". Parts unsuitable for wet cleaning were done with fresh Rodico Premium.

The circuit board was inspected and cleaned, again using fresh Rodico Premium. The circuit board was returned to its light proof container and I cleaned and inspected the coil.

 

Question from the unitiated, why does the circuit board need to be protected from the light?

 

Who makes that press? It looks very nice.

 

It's just something I noted some time ago when servicing a Seiko Chrono with a caliber 7A28A.





I don't know if it's essential to protect the CMOS chip all the time, but it doesn't hurt to do it.

 

I guess some company in China. I bought it a few years ago to replace a cheaper version and as yet I haven't had the need to upgrade.

Just Google "watch crystal screw press".

 

Out of interest Jim do you press the crystal straight in or do you press a little then rotate the case then press again?

 

Nice read Jim as usual. Looking forward to updates.

 

First press is light to check that the crystal has seated evenly in the gasket, then it's centred/set up level again and pressed in. I do rotate 90º for a final press, but don't know if it's needed or a recommended procedure.

 

That's cool. I have read about those rings in the old school bezel assembly systems but never had any in my hands.
I assumed that 7548' ring is the same as 630* ring, but no - 630* rings have L-shaped cross-section while yours is flat.
.


So, what does that ring do? Is it still engaged in fixing the crystal?

 

Well I called it a bezel ring.
As per your diagram (which I should have used as a reference) it is actually a "Glass Fixing Ring" and it does have an L-shaped cross-section.

 

Re-assembly of the movement starts with the crown/stem being lubricated and installed, then the setting parts are fitted to hold the stem in place.



Then we start the installation with the battery terminal and centre wheel and centre wheel bridge.



Followed by the rotor stator, reset lever, step rotor and the remainder of the train.



The coil and circuit block get fitted, the old battery is fitted for a check to see that all is working correctly.



Back to the other side and the day/date parts are put on and checked. And that's enough for today.

 

One of the checks required after assembly of the wheel train is to confirm correct operation of the "hacking" mechanism.


And here it is in operation.

 

Argh! I'm hopeless.

I get so involved with the task at hand I forget to take photos.
After the dial and hands were fitted it was cased up, given a new battery and will run for a while on my bench so I can keep an eye on it for any problems.

So, all done.



I think it turned out quite well.

 

PS: In closing, didn't anyone notice that it's not actually a 7548-700B as I titled this thread.

The observant among you should have twigged that it's actually a 7548-7000!

 

Terrific!

 

Cool graphics Jim