It begged me to save it... TIMEX Expedition (Chinesium Era)

[mnementh]

...and I was weak. Well that, and my "crusty old farts who shop crusty old crap on Tuesdays" discount made it cost all of "three-fitty". I didn't want to pollute the Japanese section with this; all y'alls have been tolerant enough of my Fossil habit.

Anyhoo... I'm gonna pop the cover off it; I figure worst case, I get a spare band for something else.


mnem
one boot in the arse to a customer, please...

[mnementh]

So, when last we looked in on our noob from New England, he'd just promised to crack this crusty ol' TIMEX open and see what was what. As you can see here, this has happened... and it's surprisingly not that bad. Aside from a few flakes that came in while popping off the back, it doesn't appear there's any intrusion into the movement. Time to gut it.





Here's what it looked like after pulling the stem and levering the movement out. A few moments with a soft makeup brush ensure the few flakes lying on the plastic of the movement were evicted before they could get inside. Careful prying separated the bezel; I wasn't sure it was separate at first.

It is not, however, rotating; it is a fixed piece. No idea why they added all those machining steps, unless it was to be able to alter the style with different bezels and use the same core case unit across many models. The case is heavy-chromed brass with silver electroplated over top of that to make the patina you'll see in the final pics. The dull grey you see here at 3 and 9 is actual wear through all of that to the base metal. After this shot, the movement was placed in one of my little storage tubs...

Cleaning it up involved a couple sessions with sharpened chopsticks & plastic prybars followed by Dremel & buffing pad with rouge. It was possible to get rid of all of it, but it did take polishing down to the bare chrome and brass. Still a good bit of learning on what rouge will and won't take off, and using different angles "to get in there". I also discovered I need to be more judicious when choosing a tool to open cases not made of uber-tough stainless steel. I made a couple small nicks in the brass with the dulled paring knife I've always used; a proper case knife is obviously a necessity in this hobby.

I spent a little time wiping down the band with IPA followed by leather conditioner, then worked with a Q-tip dipped in distilled water on the dial, then reassembled.

Sadly, this is where I discovered that I'd probably murdered the movement getting the crown/stem out; while it didn't take any force at all to release the stem with a plastic probe, when I tried to put the stem back it wouldn't engage properly and wouldn't lock in place. A new battery did not bring it to life, tho the Indiglo BL does work normally. I tested all the screws, and they feel tight. Measured the coil, it seems reasonable at 3.3KΩ . Probably the hacking contacts are buggered along with the stem catch/detent.

At this point I decided to finish reassembling the watch and put it away until I can decide what to do aboot it; a little research indicated that a new movement is probably 10x what I paid for the watch, and I'm not sure I like it enough to spend the money there rather than on my Dolphin.

Reassembling the bezel required making an adapter ring; the crystal on this watch sits approx half a mm proud through the bezel. This little fiddly-bit took ~10 minutes design time and ~20 minutes printing while I drank my morning cuppa... and used approx 8 cents worth of filament. I think I can afford to throw that much resources at the problem.  

Here's the adapter as used in my cheap crystal press; it worked well, though it took 3 attempts as the bezel would shift while assembling the stack. Eventually I got it right, though.

And here we are at the final shots; the watch did clean up very nicely, and I learned a lot. Especially useful was the discovery that while it won't do much for scratches, you can buff some things out of glass with just the rouge; this watch had a mark across the crystal where some soft metal had left a mark, but didn't scratch the glass. It came off 100% with no distortion of the crystal's surface.

At this point I'm not sure what I want to do with it. I mean, I'd wear the watch occasionally if I fixed it; might even spend a few bux to get there. I intend to do some diag work and see if I can at least find a heartbeat; but I may flip the thing as-is "for case parts only with defective movement". Seeing what defective TIMEX movements are bringing on fleaBay, might even net a few $$$ to throw at the Dolphin.

mnem
"Don't fall in love with your junque." ~mum

[inboost]

I've had a quick peek around the internet and I don't see any service guide info on the watch. That being said, I bet we can get it fixed. True these types of quartz movements are filled with plastic parts that can be difficult to reassemble, but I don't think it's had it's last tick if you really want to keep it. We're here to help!

[trilo]

I once opened a broken modern TIMEX and after few moments I closed it and binned it.

It looked so weird.

[mnementh]

I looked at it today.

"Yup. Still deader'n pluck."

*puts it back in the "WATCH STUPH" bin*

mnem
absolutely no compunctions... none whatsoever.

[inboost]

Aww, for a man who has more oscilloscopes than fingers I'd hope for at least a peek at the crystal to see if it was oscillating? Granted, if the black blob is dead then it's where it belongs in the drawer (we call it the healing shelf around my place). But if it's trying to live and ringing the crystal for help we gotta save it!

[mnementh]

Yeah, that's what I meant when I said "diag work looking for a heartbeat". Just... well, the can of worms is closed up for now. I have a few other projects I wanna bring to the front burner. For now.

mnem
"Sufficient unto the day is the evil thereof."   ~grand-dad

[dapellegrini]

FWIW, Some crowns are very fiddly - I find slowing rocking and twisting while reinserting can help.  Others will only seat correctly if you push in on the release lever while reinserting...  YMMV, and with really cheap stuff there is a good chance that it will all go wrong, because despite being teardown-able, they are not really meant to be serviced...

[mnementh]

So today, I got back to this... thing. First, a check for signs of life: Yup, DCV across the crystal. Time to break out the scope and Lo-Z probe...

...and yup; 32,767.6 Hz of heartbeat.




Okay, I have heartbeat, but no pulse. Hmmm... the coil output is probably NPN open-collector, so if the coil is open...




...yup, the coil is open. That's probably why no measurable pulse. Dammitt! I measured this coil as 3300 ohms earlier... I must've poked it accidentally while trying to tighten those screws... flupping shaky hands...  




So I break out the microscope, and once the big grey plastic ring and PCB are removed, it sure looks like a simple break.

Time for my tiniest soldering cartridge and my biggest magna-peepers, yo.  I even dragged my magnifying lamp out of the corner for this one.

But testing still showed the coil open; a quick look under the microscope shows why: what I thought was a single wire was actually 3 or 4; this coil is definitely beyond salvation, at least by my calloused old paws.




Since I had it unscrew'd, I decided to get a little experience taking these tiny fiddly-bits apart under the microscope & grab a few screencaps for posterity. Sorry aboot the grainy pics; this microscope is a cheapie, and it's only 1080P.




Here's the geartrain with the top plate and coil removed. The motor stator is interesting; it appears that pinch is all that defines the polarity of the magnetic flux. The rotor appears to be a tiny bit of ferrite plugged into a nylon cage that incorporates the pinion gear.

Okaaaay; enough gawking... I better try putting this back together before I sneeze and blast all the tiny little fiddly-bits to perdition.




It were a bit touch & go there fer a minute; I had a allergy attack just as I was getting my tiniest probe and ceramic tweezers into play.

But eventually I got the top plate back on, and these two tiny metal spring-things at 6-o'clock I believe form the hacking interruptor mechanism and the catch for the crown. I did try to tweak the finger on the catch-spring a little in what seemed the right direction while I had it off the movement; alas, I made it worse rather than better.




At this point I decided I'd learned all I could from the thing at this point in my journey, so I started to put it all back together. I use my phone as an assembly aid to ensure the screws went back in the right locations.




Here it is just before I pop the back on; it appears this movement started out as one of the older models, only with this grey plastic filler and PCB with additional inverter circuitry for the IndiGlo electroluminescent backlight. The grey plastic part holds zebra strip contacts for that, and a enlarged cavity for the 1025 Lithium cell.

I did Gurrgle the usual suspects and turned this up on eBay as the closest match I could find; at least the coil looks the same. But not sure if the coils is wound differently; as this movement is 1.5V vs 3V for the IndiGlo-modded variant.





And here it is back together yet again; a shame really, as this watch did clean up nicely.

Thanks for riding along as I fumble & flail about finding my way; I'm certain I'll look back on this learning experience one day and not believe some of the things I've put down here.

mnem

[inboost]

Hey great attempt at resuscitation there mnementh! As you said practice helps with confidence in working on these so the low risk of digging into a broken movement was worth the time if you ask me. I have never been able to save a coil myself, but I think trilo managed to from memory. It's all about the damage of course. As for coil values of 1.5v vs 3v that could probably be explored by looking into some Seiko tech documents. They list the coil resistance and if we found two simple quartz movements to compare, one powered by 1.5v and the other by 3.2v then we'd have a pretty definitive answer. One caveat would be to make sure the hand sets are similar in mass. High force movements to move giant hands are a thing. I would expect the coils to be different between the movements, as with a higher forward voltage it ought to consume more energy which is unnecessary in a watch. Keep trolling for another one and you'll have a swapper some time down the line!

[mnementh]

Yeah, it's hard to say actually re: the coil impedance. In principle, it's easy enough engineering to limit the pulse current with either a simple ballast resistor or by changing the gain of the last transistor stage via altering the biasing.

mnem
tzzzt.

[trilo]

Sept 25, 2023 4:28:52 GMT -8 inboost said:

Hey great attempt at resuscitation there mnementh! As you said practice helps with confidence in working on these so the low risk of digging into a broken movement was worth the time if you ask me. I have never been able to save a coil myself, but I think trilo managed to from memory. It's all about the damage of course. As for coil values of 1.5v vs 3v that could probably be explored by looking into some Seiko tech documents. They list the coil resistance and if we found two simple quartz movements to compare, one powered by 1.5v and the other by 3.2v then we'd have a pretty definitive answer. One caveat would be to make sure the hand sets are similar in mass. High force movements to move giant hands are a thing. I would expect the coils to be different between the movements, as with a higher forward voltage it ought to consume more energy which is unnecessary in a watch. Keep trolling for another one and you'll have a swapper some time down the line!

Wasn't me. It was a circuit I repaired with silver paint (since failed).

But I do remember someone has recovered a coil. I think I have also read that some people have used the same stuff to repair coils, that you use to repair broken rear window heaters on cars.

[inboost]

Yeah trilo, conductive silver paint is a pretty weak substrate to work with. I have never had much success with it myself.  The real trouble with the coils (any for that manner) is that the wire is enameled so it's doesn't short it's self against adjacent windings. The enamel by nature won't take solder and won't easily come off. I imagine there is a trick to it, but mechanical scraping is all that has ever worked for me. I can't scrape the coil wire on a watch, it's too thin.

[trilo]

Yeah, the coil painting method works only if the wire is broken from somewhere in the middle and I bet it's a hit and miss.

I think searching "coil repair" should bring up that post whoever it was.

EDIT: I think the silver paint I used for my circuit, was supposed to have some kind of binder, but customs had smashed the bottle and I had to go with scrapings. I think that if I would have been able to mix the paint, I might have had a better success.

Won't be trying it again, because after VAT and postage it wasn't exactly cheap to have it delivered in pieces...