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AndyHull

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AndyHull last won the day on January 20

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About AndyHull

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  1. AndyHull

    Revisiting an old hobby

    Some light bedtime reading. It cost slightly more than the original 3' price tag, but allowing for inflation I think it will be worth it.
  2. AndyHull

    My Demagnetiser is Magnetising

    A quick back of the envelope calculation suggests the LED is drawing about 3mA, so it wont be very bright, but by the same token the resistor is operating at a reasonably safe level, assuming it to be 1/2 Watt. If as may well be the case, it is a 1/4 Watt, then don't hold the button too long (not more than perhaps 30 seconds max, which is all you need anyway), or the resistor will get pretty hot and if repeatedly stressed like this, eventually fail. If the resistor fails (it would generally blow open circuit), it is no big deal, the unit will still operate, but the light wont work. If the resistor fails, or starts to look a little cooked over time, swap it out for a 1W 100 k Ohm replacement. Oh, and perhaps rather obviously, don't operate it with the back cover off, as all of that wiring and soldering is live at mains voltage.
  3. AndyHull

    My Demagnetiser is Magnetising

    That device is actually incredibly simple, albeit slightly crude. The circuit appears to be as follows... Part one is mains in, through a small switch (possibly mains rated, possibly not, but given the long shafted plastic button, not something I would worry about) which energizes a good old fashioned 1980s style wall wart transformer, from the days before even the cheapest wall wart had a switch mode power supply in it. I can't see the output side of the transformer, it may have a small resistor to load it up and increase the magnetic field, or it may simply be open circuit. The magnetic field from that does the actual degausing. Part two consists of a high value resistor (Brown Black Yellow = 100k Ohm) and LED (across the mains, slightly dubious practice, but not that dangerous), the LED only lights when the button is pushed. One thing I would recommend is to ensure you have a 3A or even 1A fuse in the mains plug. From a safety perspective though, as cheap goods from China go, it looks reasonably safe. If the switch fails closed, the thing stays on (not a problem), if the switch fails open it fails to energizes and the light stays off.. also not a problem. The only issue is that the unit has no built in fuse, so you would be relying on the plug fuse to blow if the transformer winding failed shorted, hence the comment about using a 3A or 1A fuse. It certainly looks a lot less likely to burn the house down than a lot of badly constructed modern cheap wall warts, but I would still recommend unplugging it when not in use. I might even get one. At round about a fiver, shipped from China, it is probably as easy and cheap to pick up one of these as it would be for me to go through my electronic scrap bin to scavenge the parts.
  4. AndyHull

    Watch of Today

    There seem to be plenty of Mao waving in various poses, but the smoking ones appear to be less common. I say less common, but presumably since these are "tourist tat", that probably means there are likely to be millions of them in circulation, but few of them on ebay. There is this, for those on a slightly higher budget. https://www.ebay.co.uk/itm/14k-gold-enamel-Omega-Chronometer-Watch-awarded-by-Chinese-Chairman-Mao-MINT/163393858948?hash=item260b086d84:g:d6AAAOSwdrpb-UK1
  5. AndyHull

    Revisiting an old hobby

    I think we can call this fixed.. well at least it agrees with Solar(R) Quartz time, so I'll call that a win. I'm going to bring the Indian one with the separate alarm spring home with me, and fix it later. I couldn't bring myself to throw it out.
  6. AndyHull

    My Demagnetiser is Magnetising

    I suspect that the coil must be being energized with DC rather than AC, if it is magnetizing rather than demagnetizing. However without knowing what is inside the thing it is difficult to see what might have failed to cause that problem. If there is a circuit inside that converts mains AC to DC, to high frequency AC, which is a possibility, then if the oscillator failed, it would produce a static magnetic field, rather than the necessary alternating one. Pop the cover off it and let us see both sides of any circuit board, and I can refine my wild speculation. Old fashioned colour cathode ray tube degausing coils used a slightly different and much simpler arrangement, however if they failed, then they tended to simply stop working, and either pop the line fuse, or your TV would slowly develop some weird colour artifacts as a result. In summary, show me some pictures of the "brains" of the device.
  7. AndyHull

    Watch cases

    I need to stop looking on ebay. It isn't good for my wallet. NOS (new old stock) - 4 off 18k Gold plated 10 micron - £2.37 ea. (+P&P) - Now all I need to do is figure out what I'm going to do with them. I have lot of ideas, and even a bunch of NOS dials, and a random assortment of hands, but I'm open to suggestions for movement, dial, hands strap etc. Maybe I should run a separate dial design thread to see what the combined talents of WRT come up with. However that will be in a few weeks when I get back from my holidays, and hopefully they have been delivered from their random corner of the money sink that is ebay. I'm also going to do some dial printing experiments, using a technology that is somewhat alien, yet oddly familiar, but I'll leave that idea dangling to see what wild speculation it stimulates.
  8. AndyHull

    Watch of Today

    Nice, that looks almost brand new. I've got a couple of jump hours, but mine are in the still needing a lot of TLC pile. That's the trouble with my self imposed budget, they almost invariably are in need of work. Speaking of funny... ... a good old mechanical from the land of the smoking chairman, (at least I assume he is smoking) by way of some random corner of ebay. It hasn't arrived yet, but when it does, I'll be sure to post the wrist shot of him moving is wrist, on my wrist here. It was 2nd hand, so in to the 404 club it goes, assuming it works, or I can get it working.
  9. AndyHull

    ETA GMT movement?

    Whisper it to us quietly, we wont tell anyone...
  10. AndyHull

    Revisiting an old hobby

    Thanks for the info and the good sound advice, however I'm on holiday, visiting my in-laws and family in India, so I'm many miles from my usual tools and cleaning materials. Hence the dipstick oiling and clumsy screwdriver work. In my defense, there is every chance that if I hadn't made the effort, it would probably be in the bin by now which would be a bit of a shame. It is still ticking away strongly some hours later, and keeping good time, but it will be interesting to see if it makes a good stab at a full thirty hours. I guess it all depends on how much life is left in the old mainspring, and how much friction used motor oil actually manages to overcome. If I was back in Scotland, I'd probably do a much more comprehensive job on it, use the correct oil and tools. Fix the cotton lining of the lid, and maybe even polish the brass work on the dial surround and clean the green case. Although I doubt if it has much monetary value, it has a certain charm and character that the Casio singularly lacks.
  11. AndyHull

    Watch cases

    For what its worth, this ebay search might turn up something to your liking. "watch case" fit movement Without knowing exactly what kind of case you are looking for, it is difficult to be more specific.
  12. AndyHull

    Watch cases

    There are a number of suppliers on ebay and elsewhere, however when I looked recently I struggled to find anything attractive, that didn't cost almost as much as a fully functional watch. A while back I did see lots of those cheap and nasty big copper frying pans pretending to be "Rose Gold" cases on ali express, but nothing that actually came close to the "that would do" mark, far less made me say "wow". If you do find anything that is particularly interesting, anything that has a little flair to it, but doesn't cost a small fortune, be sure to let us know.
  13. AndyHull

    Revisiting an old hobby

    We needed an alarm clock the other day, and ended up picking up a neat little Casio, but in the process we unearthed a couple of "vintage" numbers, neither of which actually went. (The lift angle is a guestimate) One was a local Indian make, the more sophisticated of the two, in that it has a separate barrel with spring for the alarm. Unfortunately it has suffered some pretty terminal damage, and is missing a hand, the front bezel and the glass. The German one however provided me with a little entertainment this afternoon. I was too lazy to head off to the local shop to pick up some clock oil, since this was just a fun little time waster project, so I nipped out to the car and extracted a couple of drops of motor oil from the dip stick. Probably way too heavy for this use case, but better than the thin film of rust that was previously "lubricating" the pinions. Some cleaning, oiling, and the occasional mild expletive as I attempted to perform the operation with nothing more than a safety pin and a completely unsuitable screwdriver, and off it went. Fully wound, it sits at +50 or so, and drops to -300 by the time the alarm has been rung a few times and the spring is getting low. I wouldn't say the rate is particularly stable, nor would I rely on it to time the launching of a satellite, but what the heck, it was dead and now it lives.
  14. AndyHull

    eta 2784 question

    I agree, shortcuts often turn out to be the long way of doing things. As the old adage goes, check it twice, fix it once, or to put it another way, you need to fully understand a problem before you can resolve it.
  15. AndyHull

    eta 2784 question

    Agreed. At some stage, you are going to have to bite the bullet and take a look at the spring, whether it is the old one, or the replacement. Besides it may be a simple fix, so you might not need to stump up for one or other or both of the barrel and/or the spring. I guess it could be simply that everything is so gummed up with old oil and dirt, that the spring simply isn't catching on the barrel. Alternatively, it might only take two minutes with a sharp file to fix the issue. Furthermore, in the extremely unlikely event that you do take an eye out with the spring, whats the problem? You can still see to type "I told you so" with the one remaining good one.
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