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Quartz watches and demagnetizers

Chopin
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Chopin Super WRT Addict

Chopin

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Some time ago I had a local advert for one of those cheap demagnetizers for sale.

A watchmaker contacted me and wanted to buy it (his own had malfunctioned) but he asked me if the hands of a quartz watch rotate if I use the demagnetizer on it. I had never heard of this thing before but I had a cheap quartz around, I used the demagnetizer on it and, indeed, the hands would rotate...

That got me thinking... Is there something behind this ? Can you test whether a quartz watch is faulty or not by simply using a demagnetizer on it ? If yes, do you test the electrical parts or do you just get to see whether the mechanical part (wheels, hands, pinions, etc.) works ?

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Ishima Super WRT Addict

Ishima

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I believe this works in the same way as some battery testers' "line clear" function that I've heard about before, but I use this regularly to 'jump start' and get less expensive quartz watches going again when doing battery changes. 
A bit like the circuit test function some battery testers have (that beep every second when detecting the electrical impulse remotely) you can use this as a basic - not full proof - diagnostic test, like the circuit test, will often show a problem it wont show every problem or give you a lot of information, but if you cannot make the hands do a full rotation no matter how you play with the position of the watch on the demag, it suggests that there's a blockage or broken tooth somewhere. 

Word of caution: it's best to not do this to a watch with the battery present.

Edited by Ishima
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Chopin Super WRT Addict

Chopin

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Basically I have a quartz citizen that is supposedly defective. I have a battery for it but I didn't try it because I'm missing the plastic insulator and battery clamp (that's how I bought it).

Could I try to see if it "works" with the demag first ? And afterwards I'll try the battery I guess...

I didn't know you can use this method to jump start movements. Thanks for that one!

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Ishima Super WRT Addict

Ishima

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Well yes, If you think of a quartz watch it generates movement through a small magnet which is given its torque to turn by the magnetic field generated around it, a considerably weak one normally. so often if a quartz watches oils start to dry or a bit of dust gets in the wrong place it grinds to a halt. Introduce a second, much more powerful, higher voltage (yet not powerful enough to overwhelm and damage the wheels) magnetic field generator, one that also oscillates much more rapidly, you can imagine how that will dislodge minor blockages like specs of dust and free up the movement of the gear train etc. 

So to answer your question about testing, "kind of" you can't prove a negative (the negative of there being no problem) but if you can find the right spot to place the watch and make the seconds hand do a couple of rotations without the hand hesitating, just progressing smoothly, then it's a good indicator that the gear train and motion work are in reasonable health. Yet that test alone won't tell you if the circuit board or coil are okay, the demag, as far as i know, doesnt work through those parts but directly effects the stepping motor. 

Also just a point of clarification in case i wasn't clear, i don't use this jump start method unless the watch fails to start up properly with a new battery. 

Edited by Ishima
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ecodec WRT Addict

ecodec

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Yes, the electric field (E&H) from the de-gaussing transformer (50Hz) UK, overrides the stepper motor control pulse and makes it run at a  random rate.  Most de-gaussing equipment for this purpose is an "open" primary coil  with the I`s missing. Just the E`s are used as the former.  The watch should be moved 2-3 feet away slowly from the the source whilst it is switched on. The electric Field then reduces over distance by inverse square law. I hope this helps.

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Ishima Super WRT Addict

Ishima

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Sounds like you know your electronics ecodec! but to clarify: moving the watch (or whatever object) away from the demag slowly is for the purpose of using the demag for its intended purpose, to remove magnetism, right? or is there a reason I should be doing this anyway? With my demag i don't get this rapid hand progression effect unless the watch is kept lying on the demag, usually at 'sweet spot'. 

Edited by Ishima
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Chopin Super WRT Addict

Chopin

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1 hour ago, Ishima said:

Sounds like you know your electronics ecodec! but to clarify: moving the watch (or whatever object) away from the demag slowly is for the purpose of using the demag for its intended purpose, to remove magnetism, right? or is there a reason I should be doing this anyway? With my demag i don't get this rapid hand progression effect unless the watch is kept lying on the demag, usually at 'sweet spot'. 

I did watch a video today where someone was using a quartz on a demag and when placed in one area the hands would function clockwise but when changing the position southwards a bit the hands would go counter-clockwise. Not sure if this is what it's all about.

Also, should I first try the battery on this watch ? As I mentioned I'm missing the metallic clamp (which I believe it doesn't just hold down the battery as it has some springs coming out that go into the movement but also seem to go towards the case back) and I'm also missing the plastic insulator.

Citizen 5810 is the movement.

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Ishima Super WRT Addict

Ishima

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Put this way: you wont do any harm either way, so it's up to you. 
I must say I'm not quite sure what movement that has off the top of my head, can you tell me the movement number?  (just incase i have anything more helpful to add) Unless that is also the calibre number? Picture maybe if you care to. 

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Chopin Super WRT Addict

Chopin

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That's because it's a damn hard/rare to find movement/watch and I can barely find anything about it either. At least they published the movement manual and schematic online. That's pretty much all that I have from it.

I have tried it with a battery (keep in mind that the battery clamp and plastic insulator are missing) and it didn't work, but I didn't short start it as I'm not sure how to do it.

I have tried it on the demag and unfortunately the hands do not spin at all...

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