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robmack

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About robmack

  • Rank
    Watch Enthusiast
  • Birthday September 20

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  • Gender
    Male
  • Location
    Toronto, Canada
  • Interests
    Electronics, watches, motorcycles

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  1. I'm not clear as to why a quartz movement could not be used as a frequency standard to confirm the accuracy. Can you please help me to understand your reasoning? The creator of Watch-o-scope recommends using a quartz movement to perform the calibration procedure on that product. The reason is that the internal oscillator on the sound card of the computer (that forms the frequency standard for the Watch-o-scope) is not operating at precisely the designed frequency and needs compensation. The quartz movement serves as an accurate input frequency standard.
  2. If you doubt the accuracy of your time grapher machine, then test it against a known standard. Use a good quality quartz movement and set the BPS to 1. Then test the quartz watch on your machine. It should produce a horizontal line. If there is any inaccuracy in the internal timebase of the machine, it will show up on the display.
  3. Hi, I recently purchased a previously-owned quad watch winder to keep my automatics fresh overnight. The price was very attractive and the pictures were good but, since the article was in a different city, I was not able to see it in person before I purchased it. When I received the package, I found out that one of the winder motors spun without driving the watch holder. The seller hadn't disclosed this problem, even though I specifically asked. It was an obvious mechanical problem which I set about to repairing. I'm documenting my findings here so that if someone in the future experiences the same problem, they might have a clue as to how to repair the problem. These winders are common and manufactured in China as per the "Made In" sticker. The winder consists of two 6V DC 10 RPM universal motors configured to drive a dish shaped watch holder. Each motor is capable of winding up to two watches simultaneously. In my winder, the right watch holder just remained stationary as the motor spun, indicating that either a belt had slipped or a clutch mechanism had failed. In either case, it was necessary for me to extract the motor assembly. I began by removing the watch holder from the shaft of the motor (remove the foam insert and then loosen the screw holding the part to the shaft of the motor). Then I removed the bottom panel since there was no other means to access the insides. Once opened, I disconnected the motor from the driver board and removed the four screws holding it to the baseplate (see photo 1 below). Once extracted and on the bench, I proceeded to inspect it. The motor is clamped in a plastic base and is coupled to an axle using a drive dog (see photo 2). When I disassembled the plastic base and removed the motor, the cause became apparent - the rubber drive dog was stripped. You can see the rubber residue that was dug out by the shaft. The receiving hole for the motor shaft should have been shaped to fit the keyed shaft (see photos 3 & 4). The rubber dog was just too soft to accept the torque of the geared-down motor. Any stalling of the watch holder transferred to damage to the dog. My solution was simple. I drilled a hole in the coupling housing and inserted a screw that would act as a key to prevent the motor shaft from rotating relative to the coupler (see photo 5). I decided to do this to both motors to prevent a similar fate for the operational assembly. Once repaired and back together, the winder was as good as new.
  4. Hi B52, Welcome to the forum. Your solution is very interesting, from the perspective of using an electret element as the sensor and the repeatability of the design using a well documented amplifier. The technical details for the amp are on the Adafruit site: https://learn.adafruit.com/adafruit-agc-electret-microphone-amplifier-max9814/downloads
  5. He'll also need the carbon brush length and spring length in its expanded relaxed state.
  6. If you have a caliper you might be able to estimate the size of brush. - the width and depth of the bruah (its cross-section) is square - The width and depth should be slightly smaller than the measured opening in the motor that accepts the brush - the length of the brush should be slightly longer than the distance from the commutator to the brush housing, possibly twice that length - the overall length of the brush assembly (brush plus spring) should be 1.25 times the length from the commutator to the top of the brush housing The commutator is the copper plates attached to the motor's rotor against which the brush rides The brush housing is that part of the motor casting which will accept the brush. It is topped by a threaded plastic cap that secures the brush assembly. If you have doubts, take the Benray motor to a local shop that rewinds automotive alternators. They will have the expertise to help you select the right brush set.
  7. Hi James, Thank you for your kind offer to help. This problem is sorted for me. I made contact with a local watchmaker who was able to supply me with a new staking tool. His price was significantly cheaper than machining a new plate, although the latter would have been an interesting challenge.
  8. I'm questioning the need for the thermostat. I watched Mark's video on watch cleaning and realized that the heating chamber is creating just warm air that dries the cleaned parts of watch rinse. So, you'd want the heater to go full on to create a very hot environment to evaporate the liquid quickly. The 60*C thermostat would hinder this and the parts might not dry properly. Even the Elma Elite schematic above does not have a thermostat in the heater circuit, just the neon bulb paralleling the heater element.
  9. Good discussion and suggestions. If I use L&R #109 "Extra Fine Watch Cleaning Solution" in an ultrasonic cleaner, should I warm the solution or leave it at room temperature? If warmed, to what temperature? I've searched multiple sites, including L&R's and this one, but not been able to find the answer. Ultrasonic cleaning machine manufacturers recommend that cleaning action is enhanced with temperature, up to a limit of about 60*C. I've read the MSDS for #109 (and #566) and they both contain the same formulations comprising volatile hydrocarbon mixtures. I would be concerned about heating to 60*C for fear of enhanced flammability and health concerns.
  10. Thanks Maclerche. Great diagram. Hammer, that's all that is needed - a series connected thermostat. Then you'll have yourself a great watch cleaner.
  11. The spring (resistor) is in series with the heating element so the full current drawn by the heater is passing through it. If you replaced the heater with one of a larger wattage rating that the OEM, then more current will be demanded from the mains, thus more current will pass through the resistor than it was designed to endure, and the bulb will burn out because more voltage will be dropped across the resistor due to the lower resistance of the larger heater (assuming a greater wattage rating as mentioned earlier). Are you positive the replacement heater had the exact same characteristics as the original? My guess is that the resistor should not be glowing; that just doesn't seem right. The replacement looks to be a Kapton heater. Is there a built-in thermistor or some sort of temperature limiting device with this heater? There's no such evidence apparent from the photo above. Are you certain that this Elma heater is designed to have full 230V applied to it? If not, you may have to insert a pulse-width modulated (PWM) controller in series with the heater to limit and manage its temperature. As a stop-gap solution, find out the characteristics of the heater and whether is can endure full 230V applied and, if so, bypass the coiled resistor with a wire short circuit. This will temporarily protect the resistor. Then, as suggested, put in a 230V neon lamp across the 230V supply rails to the heater to act as an ON-OFF indicator. Monitor the warmth being emitted by the new heater in these early days to make sure that it only warms the fluid to manufacturer specifications for cleaning (around 60 - 80 degrees max IIRC). If the heater goes full blast and overheats the fluid, then it's time to search for a PWM temperature controller to manage the temperature. These devices are readily available on Ebay.
  12. Talk with a local vinyl sign maker to see if they can reproduce the lettering. You'll probably need high resolution scans or photos for them to create the reproduction lettering. Then, you would refinish the panel and apply the lettering. The OEM lettering is normally created using padprinting techniques and you can research whether there is a local firm who can do that type of work, if you want an authentic restoration.
  13. It's coming along nicely. For the basket holder assembly, I'd see about shimming between the screw and the bushing on the new Elma holder. Shimming will ensure that the new basket holder is true. It would be nice if you can find someone with a lathe to make a custom part. That way you could secure the holder using the supplied set screw. If you eventually end up using the screw to secure the part, then you should probably use Loctite to secure the bolt; not too strong, something like Loctite Blue. Correct, the bulb isn't working because the circuit is not complete. When you get the new element and hook it up, the bulb should work. What happened with the heating element? Was it shorted out because of the rust?
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