Reply With QuoteFantastic job and write-up. Many thanks for sharing this.
Today's subject (quiet at the back, please) is a 7C43-7010 that has an issue with date change and so I thought I'd make a thread on it as she's a looker now it's finished. Well, it was nice to begin with, but I had a couple of things I had in mind to bestow it with.
First off is to remove the rotating ring and see what kind of gunk is there.
You can see the screw down crystal retaining ring in need of a clean.
With the movement out I had a chance to admire the lovely dial and hands. The 7C43-7010 is a Japanese domestic model that was made after the 7548 series. It featured a click spring on some models (7000 and 7009) or a more old skool click ball system as found on this 7010. It would feature the Professional 200m text on the dial as was seen fleetingly on the transitional 7548-7010 that came a year earlier and only spanned about a year of production. The 7C43 would be produced from late 1985 all the way to 1991. The movement I think suffered as a result of taking over from the 7548 series and a common occurrence is the issue we are confronted with here. But if looked after they will last a long time to come, and who can deny the good looks of the dial in combination with the those painted hands?! Not I.
With that waffle over, not knowing how accurate that info is, I'll move on straight away to what I wanted to find out was the issue, and hopefully the only issue confronted with.
If you take a look at the white date driving wheel at 9 o'clock you can see the finger has been bent and bunched back on itself. This is as a result of the date being changed manually during its natural progression between 9pm and 3am.
Once I'd removed the dial and hands and put them away safely I like to get on with the case and crown setup.
Using big bertha I removed the retaining ring carefully. They're on there quite tight!
I say the magic words "cuppa tea, please" and I go back to the room to see the job finished.
The chapter ring cleaned up slightly and ready for the gasket seating ring, the crystal gasket, a new 320W48 crystal and then the retaining ring to be screwed back down.
Quite an improvement and so now I can't wait to get the movement done!
First is to clean the crown and sorted out with a new gasket.
The crown is very similar to the 6309/7548 crowns, but has a subtle difference in shape. The female stem is also quite different but it's pretty much the same set up in that it's a two part stem system with a spring that is held with a stem washer to keep it in position. Without the washer the female stem is quite unstable.
Movement parts laid out, well, some of 'em.
Mainplate cleaned and dried using pegwood and hot soapy water then rinsed with distilled water and isopropyl and then finally a dunk in isopropyl before drying quickly.
You can see the mainplate is some kind of plastic and it is quite fragile. Nothing like the sturdy 7548 mainplate that came just 6 or 7 years earlier and would still be made as this movement was in development.
The keyless is installed in a fairly precarious way, held down in its entirety by a friction fit plastic part known as the circuit spacer that friction fits over the screw posts. Some are quite worn and so are easily popped off the post. This one, once the setting lever spring was installed and pressed against the setting lever where it really tries to spring free, was actually doing its job and maintained everything in position.
Before I get to that part I install the rotor stator, step rotor and train wheels.
And so now I install the circuit spacer mentioned earlier.
You can see how the spacer fits the gaps left prior to its installation and how there isn't all that much to hold it in place. The negative battery contact must be installed prior to the circuit spacer where the next step is to install the coil - which was tested to be within its acceptable range of 2.1 and 2.5 kilohms at 2.3 kΩ - and then the circuit itself.
And so with nearly being done here once I installed the anti-magnetic plate I start on the calendar side and for that I needed a replacement part.
The calendar side is very straightforward, situate the date driving wheel, hour wheel, various setting wheels and then install the date dial and date dial guard before finally fitting the day wheel and the the snap for day star with dial disk.
Installation of the dial spacer, dial and hands after making sure there is no dust or specs of whatever is floating about!
And then case the movement.
You can cut the negative or positive pattern on the circuit block to lose or gain 0.26 seconds per day. The flashtest told me that this was running at +0.45 spd. I didn't want to essentially cut into the circuit to compensate because I am not that bothered by making it +0.19 spd. :)
But it's something that could be done although I much prefer the trimmer on the 7548 for easier fine adjustments.
And so what was remaining for me to gift this watch? I thought that It deserved a perfect rotating ring I had spare.
What a lovely looking 7C43-7010! :cool:
Fantastic job and write-up. Many thanks for sharing this.
I have a 7C43-6010. The crown had seized up but Duncan sorted that out for me last year. These models are small but that’s fine with me. It’s also very accurate even by quartz standards. Big thank you to Bodo for putting this restoration in the spotlight.
Great work as always and what a beautiful watch!
Thanks all. I think the mid size divers like the 7C43-60s and the 6458 are overlooked a lot but are nice watches and wear well. I've been wanting to buy a 6458 for a while now. The dials are also really smart on them. Especially the 7C43-600A.
Great work as always and it is without doubt a Seiko classic.
Lovely looking thing.
Never had a 7C43. Love the white hands on those
Hard to believe it's the same watch. Excellent job, sir!
I'd call that a result, nice handy work.
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