Seiko 7548. . rescue

[anilv]

Hi guys..

I don't really like working on quartz watches but I do make an exception for the Seiko 7548. I came across this at a flea-market for MYR20 (USD5) so I figured I'd try to get it working. Its actually a 7546 but theres not much difference. The 7548 has five jewels and the 7546 has to make do with only four.

The hands have the usual black stuff which is what remains of the original lume. First thing I checked is if the hands set, unfortunately it only does part of the way. Forwards the minute hand sticks at the 50 minute mark and backwards it gets stuck around the hour mark. Day date sets ok.

Typically grotty caseback. This is a 7546-7130

It has a full length bracelet.. that's good!

What's not so good is the amount of dirt. Those with a weak stomach should look away now.

I finally open the caseback and look inside.... what I see is usually enough to throw it into the bin.

The battery needs to be physically pried off as the corrosion has made it stick to the movement. Once removed I find this. The corrosion is pretty bad but I've seen worse. In this case the two contacts for the battery are still present and stand up to the prods from my tweezer. Sometimes they are corroded beyond use and break off.

The dial resembles a starry night sky. You'd pay a lot of money if this was a high end swiss watch but this is bassically a reaction from the cases released when the battery acid oxidises. That sh\t wont buff out.

The stuff under the dial is the same as on the 6309 automatic movement. Looks good so far.

But the hour wheel was stuck to the cannon pinion and thats was what made setting the hands impossible. When this happens the keyless works usually suffer broken/worn teeth as people try to force the crown around. Those parts on this watch look ok.

Here we have a picture of the underside of the date advance. The date advance is made of plastic so its in pretty ok condition but the mainplate has a lot of corrosion.

Next off is the circuit block. More corrosion (the black stuff).. it can be scraped off with pegwood.

And the coil is carefully lifted out and put away safely.

Here we can see the effect of the battery juices on the watch mainplate. train bridge is heavily discoloured and most likely the pivots as well but its in the battery cavity that the corrosion is heaviest.

The (+) contact (held by screw) shows sign of corrosion. If this breaks off the movement is not worth repairing.

but luckily it comes off in one piece.

I finally remove the train bridge and lift it off. I made a mistake here as the stem is out and the movement is 'hacked' with the hacking part contacting the wheel. Mot really a problem but more important to remember this for the assembly. The wheels are stuck in the pivots so thats not good. Need to inspect them carefully to see if they are reusable.

Reference pic to show how the various wheels go together.

Bare mainplate ready for cleaning

 

So is the watch worth fixing? Frankly no. The dial is beyond salvage, the damage to the wheel pivots may affect the performance of the watch (surprisingly the pivots look good at high magnification) but the most important issue is the coil and circuit board. They are no longer available from Seiko and this particular watch is never going to be worth the money to source one from other sources.

Having said that.. I will check the coil and circuit board and if they are in working condition then I will re-install it and use the watch for a while. Even if I do get the watch to work, I foresee that the eventual fate of the movement will be as a donor for a 7548 diver watch as this seems to be the only quartz watch still in demand.

Will post updates.

 

 

 

 

 

 

Edited August 3, 2018 by anilv

[jdm]

Moved to watch chat until completed with reassembly pictures and the final outcome.

[anilv]

Screw it...  I'm done 

[Mark]

Moved to watch chat until completed with reassembly pictures and the final outcome.

Why? It's an ongoing project.

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[clockboy]

An interesting project I have found this company good for vintage Seiko bits. Always worth a visit when considering taking on a re-build. 

https://speedtimerkollektion.com/shop/index.php

[Pip]

Hope not@anilv as I want to see how this project comes out mate! There’s not enough people working on my lovely Seiko’s on here so I appreciate it when people show their work so I can learn from them.


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[AlexeiJ1]

Brilliant. I found a similar Seiko, it was 50 cents at a market. 7546 movement, nearly identical.
It had a stuffed crystal. absolutely filthy case/movement back, corroded battery, etc, etc. Missing end link from strap.
However after cleaning it gently and using rodico on the dial, I was able to create a wonderful watch worth wearing.

The patina on the dial is just amazing. The green oxidation from the plated crystal ring and the brown rust from the crown wheel/keyless make it look like a oyster shell. Really nice look. The only problem is the movement number got worn off the dial, but you can still see JAPAN MADE.

I havent  stripped the movement yet but I blew it out and oiled it with 9010 and has been running +1 sec/day for nearly a year now.

The crystal cost a whopping $3 from Cousins. End link was 25 cents.