As I remember, most CRT TVs had two components in the degausser circuit--a thermistor and a varistor. At turn-on, the resistance of the thermistor was low, and the resistance of the varistor was high. As current through the thermistor to the degaussing coil heated the thermistor, its resistance went up, and the increasing voltage to the varistor caused its resistance to go down. Net result was that after a few seconds of current to the degausser, the current was gradually switched over to go through the varistor to the TV power supply to start it up. We used large degausser coils on aircraft occasionally to remove magnetism from ferrous parts, particularly those near magnetic compasses or compass flux valves. On rare occasion, an entire nose gear strut would become magnetized by a lightning strike to the forward fuselage, and it would have to be degaussed. The problem presented itself as a sudden swing of the standby magnetic compass in the cockpit when the landing gear was retracted or extended. Extended, the gear was too far from the compass to affect it. Retracted, the strut was in the wheel well directly beneath the cockpit floor, and, if magnetized, close enough to the compass to cause a substantial deviation. Needless to say, magnetic compasses, flux valves, and other sensitive equipment had to be removed from the area before a degaussing coil could be brought near.
yes, earlier circuits used a single ptc from the mains, then 680 ohm resistor to ground, degauss coil fed in series with a varistor from the ptc and 680 junction, and ground, then they went to dual ptc in one unit, with the second ptc across the mains(but a higher resistance type), then seemed to go to just a single ptc...
Many of the later CRT degaussers used a relay that turned on and sent power to the coil for a few seconds at switch on, and then turned the relay back off. You could hear the click every time those were tuned on, and then a click again a few seconds later. I once had a CRT computer monitor like this, and it also had a manual degauss button that would energize the relay for a few seconds when pressed. It was always weird to watch the display suddenly bounce back and forth, all over the place, when you pushed the manual degauss button.
Heating things beyond their Curie point works too, then quenching them rapidly. You can also magnetise a steel bar by lining it up with the Earth's magnetic field and hitting it repeatedly with a hammer.
Personal anecdote ... When I got my first wide-screen telly I probably didn't turn it off for a couple of years (used the remote) I noticed the screen was distorting colours and it got worse and worse over about 6 months. I was ready for chucking it out. One night we had a power cut. When the power came back on the telly powered up with a "thunk" sound and suddenly all the colours were right again. I figured out for myself that the thing degaussed itself only when it had actually been turned off by the switch for a couple of hours.
Tip for a DIY degauser: the water valves in a washingmachine have fairly strong electro magnets, similar to the one in this degauser. They are fully watertight. Mount one of those in a n ABS box with a switch and you're ready to go ;) (it's something I learned about 30 years ago :p )
Most CRT's such as an old TV would go through a degauss cycle when powering up and later models especially computer Trinitron monitors had a degauss cycle you could select. At one seismic data processing company, a user thought he would be a smart ass and said "You want to see something neat" and he put a company fridge magnet onto the screen pulling all the electron beams to it. He thought it was really cool till the degauss cycle wasn't enough to remove the distortion completely, once he resigned himself to living with a screwed up screen due to his immaturity, I took the powerful magnetic fridge magnet and carefully waved it across the screen at various distances and locations to skillfully stretch out the screen back to a reasonable display and told him not to do that ever again (hopefully the degauss cycles will even out whatever wavering remained over time). Everything the degauss does can be done by hand with a powerful magnet but it takes time and skill, the demagnetizer is just a simple way of doing it and these watch demagnetizers are dirt cheap, about $15, $25 wth a quality compass to test if the watch is magnetized. If you still have a mechanical watch, these demagnetizers are worthwhile for whenever they start to run a little fast as it means the balance beam is getting magnetized perhaps by standing too close to a washing machine for too long or just walking past a transformer (mind you skillfully waving the watch around the transformer will also degauss it). Any magnetism tends to speed up the watch or even freeze it because the effect on the magnetism on the balance beam is to have it act as a shorter beam, you can see if the compass is magnetized by moving it near a compass to see if it reflects, not all of the compass apps on smart phones are sensitive enough to pick up the deflection though one of three I've tried has picked up on my fast running watch, best to use a quality mechanical compass. Used to be the first thing a jeweler would try if you complained of a fast running watch is to test it with a compass and degauss it with these cheap degaussers but now with so many quartz electronic watches, few even carry the degaussers now and would just ignore a fast running me handicap watch or charge you $200 for an overhaul which usually means sending it to a factory for six weeks. There used to be mechanical degaussers that used a strong permanent magnet which did not need to be plugged in but they were were heavy due to the shielding needed, they were mechanical as sometimes you had to spin the magnet to alternate the field. You can buy permanent magnets that you use to magnetize or demagnetize screwdrivers with, same concept, you'll trying to neutralize any magnetism that's there by applying varying magnetism to the object.
@@johnwang9914 Just so you are aware, a mechanical watch WILL start to run faster when it's internal lubrication drys out or ends up slung out of all the bearing points. The lubrication actually puts a drag on the internal parts, and slows the watch down, to which the speed is set to at the factory. A fast running watch usually means it's time for a lubrication service.
@@davelowets I have no doubt that a mechanical watch works better with oil and will eventually need more oil. I'm just saying that Seiko actually has several types of oil and grease and it's easy to over apply the oil with unpredictable results. Just look at the Seiko maintenance manual, portions of which are posted at the Seiko US website. Geesh, people's know it all egos... (Of course oil makes mechanical watches work better)
I have a bulk tape eraser which was sold to erase VHS cassettes which could likely be used like that. Same thing, it has written on it the duty cycle, something like 1 minute on, 30 minutes off. It also has some sort of temperature sensing mechanism so if you try to abuse it by operating it too long it'll cut out for a while. Whenever I held a screwdriver or something like that against it and pulled the trigger switch, it would make a scarey loud buzzing sound. What I was lacking was the idea to pull it away slowly. Thanks for teaching.
Well thanks! I bought one of the cheapie block ones hoping I could degausse my pliers, and that didn't work. So thanks for this. Now 1- I know how it works, 2- I know what to buy, and 3- listening to your accent while you explained it was a delight. Thank you!
This vid made me Remember us sticking large magnet (ripped off an old speaker) on a school CRT TV to see the effects as a kid then panicking when the TV didn't immediately recover lol.
Remember, the metal wires can be magnetized too. Something you first picked up with a magnet will be slightly magnatized a tiny bit, so it will then snap to other metals. So, to test if you correctly demagnetized a tool, test it on something you know is not magnetized.
Hi BC.C. I was a display tech on navy ships in the 90s. All my purpose built displays had a manually actuated degauss coil but I became the procurement consultant for IT when they began to purchase computer monitors because sometimes deguass was manually actuated, sometimes not. But once the ship was underway something about salt water brushing against a steel hull made periodic degaussing absolutely necessary. I was essentially put in charge on making sure we only bought monitors that had a button for doing so.
This reminds me of my grandpa's watchmaking bench from many decades ago. One of the tools was a degaussing coil, wound on an oval form and mounted in a finely finished nickel-plated frame. The gadget was fixed to a lacquered hardwood base, with a momentary line switch resembling an old-fashioned telegraph key. p.s. The line cord was attached with Fahnestock clips screwed to the hardwood.
I did an internship at Boxmag Rapid in Birmingham. It was a fantastic experience. Most of the products were custom in some way and a lot of the factory was essentially heavy engineering in the usual Brum style. One such product was a demagnetizer for some kind of piped material - maybe slurry. The pipe was about 6" diameter and the unit about 2' long (remember Stonehenge now). As a straight coil it took about 33A but when power factor corrected about 6A. And if you stuck a screwdriver in it, it got very hot very quick!
Thanks Clive I just bought one of these things and now I've seen this I am happy. Even though I had to repair the screw post which had snapped off as I couldn't be bothered to send the thing back
Interesting point about the wires in the LEDs being steel cored, which I don't see where anybody else picked up on. It's amazing how far that sort of thing is going. I had a rather extensive job a while back that had me picking up a whole box (1000') of RG6 coax cable, turns out that the center conductor is copper-clad steel, sticks to a magnet just fine. At the dish frequencies this stuff was carrying, skin effect made that not be a problem. Also a while back I was in a "Dollar Tree" store and saw a small package with some red and black wire. Figured that'd be handy and I picked it up. It's *not* copper, I can tell you that. So far I've used this stuff (rather extremely thin stuff) for wiring going between small modules of various sorts, and that's about it. My power distribution wiring also uses red and black, but that's tinned copper, and considerably heavier.
You can demagnetize stuff like screw drivers and snips by dropping them from a modest height onto a hard surface. It sometimes takes a few drops but it works pretty well and its free.
Thanks for taking it apart. Now I don’t need to open mine. But I’m sort of kicking myself for purchasing it because after I ordered it I played around with my Radio Shack Realistic tape head demagnetized and found out it is strong enough to demagnetized my watches. Which is my main reason for needing this tool.
learned about the degausing from a coworker. Showed me how to de-mangnetise a screwdriver with of all things, a soldering gun. Put screwdriver shaft in between the two wires coming out of the clamping blocks and turn on gun. Then slowly pull screwdriver through and pull away until you are about 5 to 10 inches away from the gun. Works great that way.
I recently bought one of these do demag a watch hairspring (Still in the watch!), I pressed the red button and the locknut wasn't screwed on, The button went inside and the LED indicator also went in, I contacted the seller and told him what happened and he replied 'Can you use it some more'!, I told him no because the whole lot had gone inside! I tried holding the red plastic switch first off to screw the nut on but it seemed lioke the threads were bad as that's when it went fully inside!, I opened the box up and pushed the switch through from the inside then replaced the nut whilst pushing down with pliars (And put the LED in first) and it's all working now!! 👍
Oh the irony... Needing a magnetic screw-driver to remove the last screw from the degausser. :-) And that mothbally smell, thats what I refer to as the "aroma of Chinese manufacturing"... It'd be interesting to know how/why the smell. I wonder if it's from fumigating shipments at exit or entry to a country.
Simon Johnson mothballs are traditionally made out of camphor. Camphor is also the oldest plasticiser for artificial plastics and was originally used with cellulose - otherwise, photographic film for example would have been impossible. The toxicity of camphor is rather low, and as long as the lethal dose is not reached, it will likely increase the Chinese worker's perceived quality of life, it works a bit like laughing gas. And it's available from cheap natural sources, they probably just grow the trees in their back yard. It is also used as a spice in cooking in numerous countries. Nah, that was just a load of bullshit. They really just need a lot of mothballs to protect the factories and storage areas from attack of the giant, nearly human-sized moths, and end up encasing some of the smell in the product. "China insect problem" gives over 3 million results on Google, so i must be onto something!
Hi Clive The degaussers ( good ones ) have a PTC and NTC thirmistors in one pact in an L circuit. Residual current in single PTC type tend to disturb the CRT. especially if multi standard and not synchronized to mains vertical drive.
Hey Big Clive. These cheap manual degaussers are primarily for degaussing a discolored television screen, though they will work for small metal objects. They're not really good for screwdrivers but you figured that out.
For a quick hack you could add a thermistor so it would automatically degrade the field. You could also add in a switch connected to a bridge rectifier so you could get a one way electromagnet to remagnetize your tools.
Anybody else notice how he's like "it switches on the neutral, that's interesting," but he seems to make absolutely no big deal of it. I guess he must really be used to opening up "dodgy shit" as he calls it. LOL
I used to have a TV repair shop back in the CRT days, our techs made their own degaussing coils, I never made one but it seemed to me they were a loop of wire maybe 30-40 feet long, they usually used lamp cord, I'm not sure but they might have used a resister in line. They were usually a coil about 12" in diameter, completely wrapped in electrical tape and had an inline switch in the cord. I've degaussed many a TV picture tube in my time!
I used an old electric shaver, with the armature removed. The vibrating armature held the blades. So basically I had a half a transformer, and placed tools or VHS tapes in the open poles. I even used it on my old TV screens too, in the early colour days.
Literally was having this issue all night tonight whilst building a cheap Chinese DIY FM radio. Odd I just found this video looking through your channel. lol
Thanks for the video. I tried that trick on one of my microwave oven transformers and it worked perfectly. Perhaps it could be done with AC step-down transformers like a 22VAC I found on the digital timer from a microwave oven, but I don't know. The transformer inside your degausser reminded me of one of those. AC step-downs are much safer, but anybody with an MOT and HV experience should try my method.
Was this the same principle as used in the WW2 ship degausers used as protection from magnetic mines? I know a large cable was wrapped around the outside of and the hull wiped with the cable.
My first use of a degausser was an electricity meter potential coil, potted in polyethylene... That's also where i learned that when you remove the core(tool), the coil loses the reactance, and gets really hot really fast
Mechanical watches are sensitive to magnetic fields, and the hairspring can become magnetized. When magnetized the watch will not keep proper time. Over time a mechanical watch hairspring can become magnetized from the Earth's field. The use of a demagnetizer for watches is able to be used to demagnetize the watch. With the use of mobile phones and computer devices mechanical watches tend to get more easily magnetized. I am using the same demagnetizer shown in this video to demagnetize my watches. It is very effective and works very well for my watches. I like electronic quartz watches for accuracy, and they are not easily affected by magnetic fields.
Thank you for your comment. Most times I learn from the comment section. For a deeper understanding of the magnetic field influence on rotating assemblies within the Either, I’d suggest educating oneself on “The Law of Hysteresis.” Things are not as complicated as we’ve been taught. Again, thank you.
Those old degaussing coils made for servicing CRT's (about 12" in diameter, mine is a 'CG Electronics' model 9317 but there are others) are great for general shop use. Big enough for most any & all hand tools, vise jaws or whatever comes along. Like you say, the trick is to wave the tool around within the coil, then separate to double arms length before releasing the switch. In my experience 5 seconds or so total cycle time is sufficient, and and be aware of your surroundings; if you release that switch near anything ferrous it could end up magnetized. I always remove my watch, cell phone and other electronics from the immediate area as well. The old coils work extremely well on tools and the like, but seem to have little if any effect on permanent magnets, and are poor magnetic media erasers[1]. Back in the 80's I was in the coin op video game biz; many/most of those monitors were far to cheap to incorporate integral coils, and degaussing them was a frequent chore... I hate magnetized tools, but like the flexibility of being able to magnetize whatever for some specific task and degauss once done... [1] Still don't know how the new 'chipped' credit cards will fair around said coils... I also don't know about their effect on pacemakers...
I wouldn't expect a degausser to affect a chip card much. Those are just a buried microcontroller with some pads like a SIM, there's no long leads to act as an antenna. RFID cards would probably be a different matter, though; those have a long coil inside the card that the MCU both takes power off and modulates for signaling, and I bet a degausser would induce enough current to fry their tiny little brains.
I used to wave magnets in front of my crt monitor, just to hit the degausser function and hear that satisfying 'thunk' and watch the screen wobble... good times.
I bought a degausser many years ago(late 70's) to degauss my tape recorder heads. Even though it came with basic instructions I never could work out how or if it really worked or caused damage to the machine. Still have it. I'll try to demagnetize a screwdriver.
You've given me an idea for using a micro-controller to slowly lower the voltage to the coil, so that all one would have to do is press the button, and wait for the LED to go out, and eliminate the need to slowly pull the tool out of the field. Hmmmm....
A watch can die from being around a magnet as the hands can't pass each other (as an example) - maybe the most common issue when magnetized and newer tech try to avoid that. I just rebooted a third one from ebay. It was something I learned in the 80's with a tape deck and a shop owner looked at me odd with my desire to order a demagnetizer but I played with the heads for each tape with a screw driver and could hear the difference.
Brian Ullmark You get the same problem with sheet metal guillotines. Cutting steel gradually magnetises the blades and cut parts eventually start sticking to them. But you need a much bigger demagnetiser/degausser than this one.
Another example of china's best...where they make this degausser on one end of a bench ...and at the other end, they make moth-balls! That momentary switch is guaranteed to last from 11 til noon...at least ten pushes! Thanks for another great video BC!
I have often wondered, how my tools got magnetized? I have purchased new tools that displayed a magnetic field, but still wonder how that field gets more intense each year, throughout the banging and abuse they take.
this will also unstick a cheap watch the seconds hand will do a full revolution in 1 second approx because of 50 hz, i made one for a market trader friend 10 years ago with two settings one strong to unstick the watch and one setting to run it for a while, also use lighter fluid for a stubborn jammed watch worked a treat still working today lol, give it a go with a cheap battery watch gr8 vids keep em comming.
Just put the tool through the loop of a soldering gun (like a Weller) and it will work too. Can make a larger loop for larger tools out of a piece of house wiring copper. Of course it will take longer to do.
Hi Clive. The thermistor arrangement used on CRT degaussing coils actually uses two thermistors. There's the PTC one in series with the coils as you describe plus an NTC one in parallel with the coils and closely thermally coupled to the PTC. With this setup the residual current through the coils once their job is done reduces to near enough zero - without the second thermistor there would always be a current through them.
SeanBZA With a single PTC device you still have to have a current through it in order to keep it hot and high resistance, and this current would have to go through the coil. Adding a thermally-coupled NTC shunt device across the coil diverts this current and eliminates any picture disturbance.
Graham Langley True, but they made some hyperabrupt 2 wire PTC units that when hot stayed hot with only around 10mA of current, and then in some sets they had a very high value damping resistor across the coil as well to reduce the current further. The 3 terminal ones did do a better job, but many sets only used the 2 wire arrangement, though they did go up nicely when they failed. Still would rattle like a castanet when failed.
SeanBZA I've not not come across those, but then I've only pulled my own TVs apart to fix and I've not had to do that for many years. Last one was a neighbour's curved widescreen Toshiba with '99 batch codes that we were taking to the dump earlier this year and that had a three-terminal PTC+NTC one.
Graham Langley My monitor had one connected with a relay and sensing circuit to completely disconnect the PTC/coil assembly when the current dropped enough.
I'm just imagining what you could achieve with a microwave oven transformer with its secondary removed, and with the yoke opened up at one end [to form an 'E' core]. The magnetic flux would be immense!
I use a handheld version of this for degaussing tape machines. It doesn't have a switch so it's always on when plugged in. Covered in warning labels about not leaving it plugged in. It was somewhat scary getting used to it at first as it vibrates slightly and gets warm in your hand. It can take some time to properly demagnetize a large tape machine (sometimes multiple machines) and I'm always worried about leaving it on for too long. Any idea how long too long would actually be?
I 'worked' at a local radio station a long time ago and walked in on one of the dj's erasing some jingle carts ( similar to 8 track cartridges with magnetic tape inside on a loop ) to do new jingles one afternoon using a unit not unlike this one. He had the whole box of carts next to the machine and was busy selecting odd ones he wanted to erase, buzzing them and putting them to one side. Language unsuitable for the female ear was used.
I bought a small brushless motor and took out the rotating bits and made my own degausser. Just plug it in and run any parts and pieces through the center hole without touching the sides and it's MUCH more effective than that little thing.
You didn't mention the other use of the degauzer Clive. That of cleaning audio and video tape. I have a quite large unit which was used in a radio station for cleaning audio from their logging tapes. Plus of course there's the long Wand used to degauze coloured cathode ray TV screens. Oh yes and a smaller unit for cleaning cassette tapes in compact and 8 track formats. I guess we shouldn't forget the small erase heads in all Tape type recorders, both audio and video. I also purchased a dumb unit from BangGood which has a plastic enclosure with a magnet sealed inside. It had holes on one side to Magnetize your screwdrivers and holes on the other side to demagnetize them. Not very good sadly, I much prefer the large audio unit for tools. Great videos mate, all the best from downunder.
I was trying to look up some of your vlogs on some of your kit building,when the power supply kit ,I am building gave me a problem,I am sure you have Had a foil u were scolding come off,what did you do to complete to the circuit,did you make a jumper,or scratch off some more foil to make a jumper,I thought I would ask a expert.some of these Chinese kits have been a little hard no that I am older and the kits are so small. The kit I am trying to build is a LM 317 power supply, maybe it a kit you have already done,thanks for all your videos.
It's great because it's so cheap you don't really care if you use it once or twice and then it stays stored in the garage since you really don't have your watch magnetized very often
Reminded me of demagnetizing audio casette players. Got to move the widget away very slowly for first few centimetres, but that wouldn't thrill us viewers here :)
It is also installed in battleships because all the electric stuff can magnetize the hull making them point north. Think 6 pair (all twisted in a cable, helix) of 500 mcm wire pulled around the entire hull of a destroyer. This is often what confuses dimwits into thinking the Philadelphia Experiment is reality. Degassing is common in large magnetic structures.
Clive, when we put a magnet near the screen of a CRT, why does the effect persist? What is being magnetized. I thought it was just glass and a phosphor coating. Does the phosphor coating have grains that get re-arranged or something?
+Derrick Blackburn There's a metal shadow-mask behind that makes sure each electron gun only hits its specific colour of phosphor. The residual magnetic field can be removed with either an external or built-in degausser.
Must look to see if I still have one fish tank air pump, which uses the same coil. Comes with a case as well and a cord, though I would have to put in the switch. That unit looks remarkably similar to the fish tank pump housings as well, probably made by the same factory.
SeanBZA Careful - without anything to complete the magnetic circuit the inductance will be a lot less and it'll get quite hot very quickly. If it's got a one-shot thermal safety cut-out embedded in the winding you'll only get one go at finding out how quickly. A core designed to go in a demagnetiser will be wound differently, although it'll still only be rated for intermittent use.
Graham Langley It is open, with only a ferrite magnet waving in the breeze....... They did look very crispy though after a few years moving that rubber diaphragm though. not helped by them all seemingly to be made with the core cover being ordinary painters masking tape. That almost always was a few brown crumbles inside the bottom of the rubber base when you opened it, along with the black rubber crumb from the pump diaphragm falling to bits.
SeanBZA My baby degausser is the coil from a defunct hair trimmer. It's an E-core and drove a magnet that oscillated back and forth between the open legs of the core - there wasn't much coupling. But without it 30 seconds is as long I reckon it's safe to run it for.
As I remember, most CRT TVs had two components in the degausser circuit--a thermistor and a varistor. At turn-on, the resistance of the thermistor was low, and the resistance of the varistor was high. As current through the thermistor to the degaussing coil heated the thermistor, its resistance went up, and the increasing voltage to the varistor caused its resistance to go down. Net result was that after a few seconds of current to the degausser, the current was gradually switched over to go through the varistor to the TV power supply to start it up.
We used large degausser coils on aircraft occasionally to remove magnetism from ferrous parts, particularly those near magnetic compasses or compass flux valves. On rare occasion, an entire nose gear strut would become magnetized by a lightning strike to the forward fuselage, and it would have to be degaussed. The problem presented itself as a sudden swing of the standby magnetic compass in the cockpit when the landing gear was retracted or extended. Extended, the gear was too far from the compass to affect it. Retracted, the strut was in the wheel well directly beneath the cockpit floor, and, if magnetized, close enough to the compass to cause a substantial deviation. Needless to say, magnetic compasses, flux valves, and other sensitive equipment had to be removed from the area before a degaussing coil could be brought near.
yes, earlier circuits used a single ptc from the mains, then 680 ohm resistor to ground, degauss coil fed in series with a varistor from the ptc and 680 junction, and ground, then they went to dual ptc in one unit, with the second ptc across the mains(but a higher resistance type), then seemed to go to just a single ptc...
airplanes mechanic detected. ;)
Many of the later CRT degaussers used a relay that turned on and sent power to the coil for a few seconds at switch on, and then turned the relay back off.
You could hear the click every time those were tuned on, and then a click again a few seconds later. I once had a CRT computer monitor like this, and it also had a manual degauss button that would energize the relay for a few seconds when pressed. It was always weird to watch the display suddenly bounce back and forth, all over the place, when you pushed the manual degauss button.
Sounds like throwing a thermistor in this demagnetizer could make it automatic... #badideas.
My grandfather taught me to demagnetize things by beating the shit out of them against a bit of metal. It used to work pretty well.
AnthonyH That gets the electrons going again, i have heard of the effect!
Eviltech Nothing quite like waking up those lazy pixies!
+AnthonyH Yes. That always worked for me. Whacking a screwdriver on a hard metal surface works wonders for taking away the mag field.
Heating things beyond their Curie point works too, then quenching them rapidly. You can also magnetise a steel bar by lining it up with the Earth's magnetic field and hitting it repeatedly with a hammer.
Yeah, try that on a mechanical watch or a CRT.
Personal anecdote ... When I got my first wide-screen telly I probably didn't turn it off for a couple of years (used the remote) I noticed the screen was distorting colours and it got worse and worse over about 6 months. I was ready for chucking it out. One night we had a power cut. When the power came back on the telly powered up with a "thunk" sound and suddenly all the colours were right again. I figured out for myself that the thing degaussed itself only when it had actually been turned off by the switch for a couple of hours.
thats one of the reasons why its not a good idea to shut a tv off on standby all the while... 😉
that only works for crts
@@WELLINGTON20 Yes I know
@@WELLINGTON20 exactly why he mentioned it
And degaussing makes a lot of noise in a CRT.
Tip for a DIY degauser: the water valves in a washingmachine have fairly strong electro magnets, similar to the one in this degauser. They are fully watertight. Mount one of those in a n ABS box with a switch and you're ready to go ;) (it's something I learned about 30 years ago :p )
Wow, that is a great idea, have a few of those around; never thought of that, thanks.
Most CRT's such as an old TV would go through a degauss cycle when powering up and later models especially computer Trinitron monitors had a degauss cycle you could select. At one seismic data processing company, a user thought he would be a smart ass and said "You want to see something neat" and he put a company fridge magnet onto the screen pulling all the electron beams to it. He thought it was really cool till the degauss cycle wasn't enough to remove the distortion completely, once he resigned himself to living with a screwed up screen due to his immaturity, I took the powerful magnetic fridge magnet and carefully waved it across the screen at various distances and locations to skillfully stretch out the screen back to a reasonable display and told him not to do that ever again (hopefully the degauss cycles will even out whatever wavering remained over time). Everything the degauss does can be done by hand with a powerful magnet but it takes time and skill, the demagnetizer is just a simple way of doing it and these watch demagnetizers are dirt cheap, about $15, $25 wth a quality compass to test if the watch is magnetized. If you still have a mechanical watch, these demagnetizers are worthwhile for whenever they start to run a little fast as it means the balance beam is getting magnetized perhaps by standing too close to a washing machine for too long or just walking past a transformer (mind you skillfully waving the watch around the transformer will also degauss it). Any magnetism tends to speed up the watch or even freeze it because the effect on the magnetism on the balance beam is to have it act as a shorter beam, you can see if the compass is magnetized by moving it near a compass to see if it reflects, not all of the compass apps on smart phones are sensitive enough to pick up the deflection though one of three I've tried has picked up on my fast running watch, best to use a quality mechanical compass. Used to be the first thing a jeweler would try if you complained of a fast running watch is to test it with a compass and degauss it with these cheap degaussers but now with so many quartz electronic watches, few even carry the degaussers now and would just ignore a fast running me handicap watch or charge you $200 for an overhaul which usually means sending it to a factory for six weeks. There used to be mechanical degaussers that used a strong permanent magnet which did not need to be plugged in but they were were heavy due to the shielding needed, they were mechanical as sometimes you had to spin the magnet to alternate the field. You can buy permanent magnets that you use to magnetize or demagnetize screwdrivers with, same concept, you'll trying to neutralize any magnetism that's there by applying varying magnetism to the object.
@@johnwang9914 The CRT would have eventually come back to normal without all the fuckery...
@@johnwang9914 Just so you are aware, a mechanical watch WILL start to run faster when it's internal lubrication drys out or ends up slung out of all the bearing points. The lubrication actually puts a drag on the internal parts, and slows the watch down, to which the speed is set to at the factory.
A fast running watch usually means it's time for a lubrication service.
@@davelowets I have no doubt that a mechanical watch works better with oil and will eventually need more oil. I'm just saying that Seiko actually has several types of oil and grease and it's easy to over apply the oil with unpredictable results. Just look at the Seiko maintenance manual, portions of which are posted at the Seiko US website. Geesh, people's know it all egos... (Of course oil makes mechanical watches work better)
I have a bulk tape eraser which was sold to erase VHS cassettes which could likely be used like that. Same thing, it has written on it the duty cycle, something like 1 minute on, 30 minutes off. It also has some sort of temperature sensing mechanism so if you try to abuse it by operating it too long it'll cut out for a while.
Whenever I held a screwdriver or something like that against it and pulled the trigger switch, it would make a scarey loud buzzing sound. What I was lacking was the idea to pull it away slowly. Thanks for teaching.
I love your videos, I literally watch them for hours at a time while at "work". I have learned a bunch and owe you many thanks!
for some tools like crescent wrenches or screwdrivers, I find that a few good whacks on the workbench works quite well for demagnetizing them
Well thanks! I bought one of the cheapie block ones hoping I could degausse my pliers, and that didn't work. So thanks for this. Now 1- I know how it works, 2- I know what to buy, and 3- listening to your accent while you explained it was a delight. Thank you!
Immaculate. Thanks very much Clive. Following your reassuring observations I'm going to buy one to degauss my mechanical watch.
This vid made me Remember us sticking large magnet (ripped off an old speaker) on a school CRT TV to see the effects as a kid then panicking when the TV didn't immediately recover lol.
Been there, some that, have the t-shirt
Kids today will never know the joy of seeing the picture on a crt go all wonkified and then the panic when it doesn't return to normal 😂
Remember, the metal wires can be magnetized too.
Something you first picked up with a magnet will be slightly magnatized a tiny bit, so it will then snap to other metals.
So, to test if you correctly demagnetized a tool, test it on something you know is not magnetized.
Hi BC.C. I was a display tech on navy ships in the 90s. All my purpose built displays had a manually actuated degauss coil but I became the procurement consultant for IT when they began to purchase computer monitors because sometimes deguass was manually actuated, sometimes not. But once the ship was underway something about salt water brushing against a steel hull made periodic degaussing absolutely necessary. I was essentially put in charge on making sure we only bought monitors that had a button for doing so.
Great explanation of the degaussing system. Reminded of my time in college! THANKS!!!
in the 70's they were selling these as cassette tape erasures . The same push button design with a bigger coil. Love the channel. Kel
This reminds me of my grandpa's watchmaking bench from many decades ago. One of the tools was a degaussing coil, wound on an oval form and mounted in a finely finished nickel-plated frame. The gadget was fixed to a lacquered hardwood base, with a momentary line switch resembling an old-fashioned telegraph key. p.s. The line cord was attached with Fahnestock clips screwed to the hardwood.
Shake Hands with Danger. Beautifully crafted and finished Danger. Love those old tools where safety was "just don't touch that part"!
Another concise video, containing everything I needed to know. Thank you Clive
You had me at 1:45 when you mentioned the high magnetic field it's putting in my tool:)
I did an internship at Boxmag Rapid in Birmingham. It was a fantastic experience. Most of the products were custom in some way and a lot of the factory was essentially heavy engineering in the usual Brum style. One such product was a demagnetizer for some kind of piped material - maybe slurry. The pipe was about 6" diameter and the unit about 2' long (remember Stonehenge now). As a straight coil it took about 33A but when power factor corrected about 6A. And if you stuck a screwdriver in it, it got very hot very quick!
Thanks Clive I just bought one of these things and now I've seen this I am happy. Even though I had to repair the screw post which had snapped off as I couldn't be bothered to send the thing back
This guy is awesome! i learn so much from him! *props!*
Thank you for the degusser class and thank you for sharing the info.
Interesting point about the wires in the LEDs being steel cored, which I don't see where anybody else picked up on. It's amazing how far that sort of thing is going. I had a rather extensive job a while back that had me picking up a whole box (1000') of RG6 coax cable, turns out that the center conductor is copper-clad steel, sticks to a magnet just fine. At the dish frequencies this stuff was carrying, skin effect made that not be a problem. Also a while back I was in a "Dollar Tree" store and saw a small package with some red and black wire. Figured that'd be handy and I picked it up. It's *not* copper, I can tell you that. So far I've used this stuff (rather extremely thin stuff) for wiring going between small modules of various sorts, and that's about it. My power distribution wiring also uses red and black, but that's tinned copper, and considerably heavier.
You can demagnetize stuff like screw drivers and snips by dropping them from a modest height onto a hard surface. It sometimes takes a few drops but it works pretty well and its free.
Thanks for taking it apart. Now I don’t need to open mine. But I’m sort of kicking myself for purchasing it because after I ordered it I played around with my Radio Shack Realistic tape head demagnetized and found out it is strong enough to demagnetized my watches. Which is my main reason for needing this tool.
learned about the degausing from a coworker. Showed me how to de-mangnetise a screwdriver with of all things, a soldering gun. Put screwdriver shaft in between the two wires coming out of the clamping blocks and turn on gun. Then slowly pull screwdriver through and pull away until you are about 5 to 10 inches away from the gun. Works great that way.
Am learning so much today! Thanks!
I really like your videos :) Thanks for making them
I recently bought one of these do demag a watch hairspring (Still in the watch!), I pressed the red button and the locknut wasn't screwed on, The button went inside and the LED indicator also went in, I contacted the seller and told him what happened and he replied 'Can you use it some more'!, I told him no because the whole lot had gone inside!
I tried holding the red plastic switch first off to screw the nut on but it seemed lioke the threads were bad as that's when it went fully inside!, I opened the box up and pushed the switch through from the inside then replaced the nut whilst pushing down with pliars (And put the LED in first) and it's all working now!! 👍
Oh the irony... Needing a magnetic screw-driver to remove the last screw from the degausser. :-)
And that mothbally smell, thats what I refer to as the "aroma of Chinese manufacturing"... It'd be interesting to know how/why the smell. I wonder if it's from fumigating shipments at exit or entry to a country.
Thank you. I was about to elaborate the same observation, but you beat me to it.
Simon Johnson mothballs are traditionally made out of camphor. Camphor is also the oldest plasticiser for artificial plastics and was originally used with cellulose - otherwise, photographic film for example would have been impossible. The toxicity of camphor is rather low, and as long as the lethal dose is not reached, it will likely increase the Chinese worker's perceived quality of life, it works a bit like laughing gas. And it's available from cheap natural sources, they probably just grow the trees in their back yard. It is also used as a spice in cooking in numerous countries.
Nah, that was just a load of bullshit. They really just need a lot of mothballs to protect the factories and storage areas from attack of the giant, nearly human-sized moths, and end up encasing some of the smell in the product. "China insect problem" gives over 3 million results on Google, so i must be onto something!
Awwwww yes the unforgettable smell of chinesium
Hi Clive The degaussers ( good ones ) have a PTC and NTC thirmistors in one pact in an L circuit.
Residual current in single PTC type tend to disturb the CRT. especially if multi standard and not synchronized to mains vertical drive.
Now that's a thorough review!
Hey Big Clive. These cheap manual degaussers are primarily for degaussing a discolored television screen, though they will work for small metal objects. They're not really good for screwdrivers but you figured that out.
For a quick hack you could add a thermistor so it would automatically degrade the field. You could also add in a switch connected to a bridge rectifier so you could get a one way electromagnet to remagnetize your tools.
Anybody else notice how he's like "it switches on the neutral, that's interesting," but he seems to make absolutely no big deal of it. I guess he must really be used to opening up "dodgy shit" as he calls it. LOL
I used to have a TV repair shop back in the CRT days, our techs made their own degaussing coils, I never made one but it seemed to me they were a loop of wire maybe 30-40 feet long, they usually used lamp cord, I'm not sure but they might have used a resister in line. They were usually a coil about 12" in diameter, completely wrapped in electrical tape and had an inline switch in the cord. I've degaussed many a TV picture tube in my time!
I used an old electric shaver, with the armature removed.
The vibrating armature held the blades.
So basically I had a half a transformer, and placed tools or VHS tapes in the open poles.
I even used it on my old TV screens too, in the early colour days.
Literally was having this issue all night tonight whilst building a cheap Chinese DIY FM radio. Odd I just found this video looking through your channel. lol
Thanks for the video. I tried that trick on one of my microwave oven transformers and it worked perfectly. Perhaps it could be done with AC step-down transformers like a 22VAC I found on the digital timer from a microwave oven, but I don't know. The transformer inside your degausser reminded me of one of those. AC step-downs are much safer, but anybody with an MOT and HV experience should try my method.
yep, remove part of the core, so the poles are 'open'...
This is the coolest thing i have ever seen!!
That blue is BEAUTIFUL! My 1997 Harley is that color.
Actually, it's not about the price of the tool, it's about the knowledge of the user !
Thank you for teaching a good lesson.
Ah, this reminds me of the crt screen days with built in demagnetisers.
DEGAUSS
And when they had not. A simple magnet destroyed the image unless you knew it could be undone.
Was this the same principle as used in the WW2 ship degausers used as protection from magnetic mines? I know a large cable was wrapped around the outside of and the hull wiped with the cable.
greetings from venezuela i just subscribe to your channel, really enjoy your videos keep it up :D
Hah!
Great vid as usual Clive.
Love it.
My first use of a degausser was an electricity meter potential coil, potted in polyethylene... That's also where i learned that when you remove the core(tool), the coil loses the reactance, and gets really hot really fast
Thanks, another interesting video.
Mechanical watches are sensitive to magnetic fields, and the hairspring can become magnetized. When magnetized the watch will not keep proper time. Over time a mechanical watch hairspring can become magnetized from the Earth's field. The use of a demagnetizer for watches is able to be used to demagnetize the watch. With the use of mobile phones and computer devices mechanical watches tend to get more easily magnetized.
I am using the same demagnetizer shown in this video to demagnetize my watches. It is very effective and works very well for my watches.
I like electronic quartz watches for accuracy, and they are not easily affected by magnetic fields.
Thank you for your comment. Most times I learn from the comment section. For a deeper understanding of the magnetic field influence on rotating assemblies within the Either, I’d suggest educating oneself on “The Law of Hysteresis.” Things are not as complicated as we’ve been taught. Again, thank you.
Those old degaussing coils made for servicing CRT's (about 12" in diameter, mine is a 'CG Electronics' model 9317 but there are others) are great for general shop use. Big enough for most any & all hand tools, vise jaws or whatever comes along. Like you say, the trick is to wave the tool around within the coil, then separate to double arms length before releasing the switch. In my experience 5 seconds or so total cycle time is sufficient, and and be aware of your surroundings; if you release that switch near anything ferrous it could end up magnetized. I always remove my watch, cell phone and other electronics from the immediate area as well. The old coils work extremely well on tools and the like, but seem to have little if any effect on permanent magnets, and are poor magnetic media erasers[1]. Back in the 80's I was in the coin op video game biz; many/most of those monitors were far to cheap to incorporate integral coils, and degaussing them was a frequent chore... I hate magnetized tools, but like the flexibility of being able to magnetize whatever for some specific task and degauss once done...
[1] Still don't know how the new 'chipped' credit cards will fair around said coils... I also don't know about their effect on pacemakers...
I wouldn't expect a degausser to affect a chip card much. Those are just a buried microcontroller with some pads like a SIM, there's no long leads to act as an antenna. RFID cards would probably be a different matter, though; those have a long coil inside the card that the MCU both takes power off and modulates for signaling, and I bet a degausser would induce enough current to fry their tiny little brains.
Subbed, good videos, keep them up.
i still have a samsung crt with a built in degausser working.
btw awesome screwdriver (the pen shaped one)
Great demo thank you.
Thank you for the informative video.
I used to wave magnets in front of my crt monitor, just to hit the degausser function and hear that satisfying 'thunk' and watch the screen wobble... good times.
I bought a degausser many years ago(late 70's) to degauss my tape recorder heads. Even though it came with basic instructions I never could work out how or if it really worked or caused damage to the machine. Still have it. I'll try to demagnetize a screwdriver.
You've given me an idea for using a micro-controller to slowly lower the voltage to the coil, so that all one would have to do is press the button, and wait for the LED to go out, and eliminate the need to slowly pull the tool out of the field. Hmmmm....
A watch can die from being around a magnet as the hands can't pass each other (as an example) - maybe the most common issue when magnetized and newer tech try to avoid that. I just rebooted a third one from ebay. It was something I learned in the 80's with a tape deck and a shop owner looked at me odd with my desire to order a demagnetizer but I played with the heads for each tape with a screw driver and could hear the difference.
I used to use a RadioShack degauser on my 8-track player. Man I *hate* those leads sticking to my nippers though.
Brian Ullmark You get the same problem with sheet metal guillotines. Cutting steel gradually magnetises the blades and cut parts eventually start sticking to them. But you need a much bigger demagnetiser/degausser than this one.
5:43 Yes it *is* (inevitable)! Take it to bits, Clive! 😁
Another example of china's best...where they make this degausser on one end of a bench ...and at the other end, they make moth-balls! That momentary switch is guaranteed to last from 11 til noon...at least ten pushes! Thanks for another great video BC!
I've actually used those very buttons in all sorts of projects and I've never had one fail yet.
+paxmowa I've had them stick with too much amperage, over too long a time span.
+BILS yeah you're right, that degauser probably pushes a few amps through it, poor thing doesn't stand a chance.
I have often wondered, how my tools got magnetized? I have purchased new tools that displayed a magnetic field, but still wonder how that field gets more intense each year, throughout the banging and abuse they take.
this will also unstick a cheap watch the seconds hand will do a full revolution in 1 second approx because of 50 hz, i made one for a market trader friend 10 years ago with two settings one strong to unstick the watch and one setting to run it for a while, also use lighter fluid for a stubborn jammed watch worked a treat still working today lol, give it a go with a cheap battery watch
gr8 vids keep em comming.
paul taplin I think that may actually be one of the advertised uses for this particular degausser.
Just put the tool through the loop of a soldering gun (like a Weller) and it will work too. Can make a larger loop for larger tools out of a piece of house wiring copper. Of course it will take longer to do.
Hi Clive. The thermistor arrangement used on CRT degaussing coils actually uses two thermistors. There's the PTC one in series with the coils as you describe plus an NTC one in parallel with the coils and closely thermally coupled to the PTC. With this setup the residual current through the coils once their job is done reduces to near enough zero - without the second thermistor there would always be a current through them.
Graham Langley There are 2 wire thermistors, designed so the coil current when hot was very low. Basically now common as a polyfuse.
SeanBZA With a single PTC device you still have to have a current through it in order to keep it hot and high resistance, and this current would have to go through the coil. Adding a thermally-coupled NTC shunt device across the coil diverts this current and eliminates any picture disturbance.
Graham Langley True, but they made some hyperabrupt 2 wire PTC units that when hot stayed hot with only around 10mA of current, and then in some sets they had a very high value damping resistor across the coil as well to reduce the current further. The 3 terminal ones did do a better job, but many sets only used the 2 wire arrangement, though they did go up nicely when they failed. Still would rattle like a castanet when failed.
SeanBZA I've not not come across those, but then I've only pulled my own TVs apart to fix and I've not had to do that for many years. Last one was a neighbour's curved widescreen Toshiba with '99 batch codes that we were taking to the dump earlier this year and that had a three-terminal PTC+NTC one.
Graham Langley My monitor had one connected with a relay and sensing circuit to completely disconnect the PTC/coil assembly when the current dropped enough.
I'm just imagining what you could achieve with a microwave oven transformer with its secondary removed, and with the yoke opened up at one end [to form an 'E' core]. The magnetic flux would be immense!
A running a/c fan motor will do it. Even a small one like a computer fan can demagnetize a watch for example.
I use a handheld version of this for degaussing tape machines. It doesn't have a switch so it's always on when plugged in. Covered in warning labels about not leaving it plugged in. It was somewhat scary getting used to it at first as it vibrates slightly and gets warm in your hand. It can take some time to properly demagnetize a large tape machine (sometimes multiple machines) and I'm always worried about leaving it on for too long. Any idea how long too long would actually be?
I would say no more than a couple minutes definitely after you start to feel it heating up. Also you could always put an on/off switch yourself.
you could also heat the object above the Curie temperetaure
Well done!
I 'worked' at a local radio station a long time ago and walked in on one of the dj's erasing some jingle carts ( similar to 8 track cartridges with magnetic tape inside on a loop ) to do new jingles one afternoon using a unit not unlike this one.
He had the whole box of carts next to the machine and was busy selecting odd ones he wanted to erase, buzzing them and putting them to one side. Language unsuitable for the female ear was used.
just curious can you demagnetize a neodymium magnet?
Yes but it is a lot more work (Heat works wonders, just get the neodymium to like, 1000C
of course, in many ways.
t
@Schwalbe262 that was an invitation to google the stuff, he could have lie to you with "no"😁
@Schwalbe262 i won't bother google that
I burst out laughing when you said "I'm going to unplug it first"
I bought a small brushless motor and took out the rotating bits and made my own degausser. Just plug it in and run any parts and pieces through the center hole without touching the sides and it's MUCH more effective than that little thing.
You didn't mention the other use of the degauzer Clive. That of cleaning audio and video tape. I have a quite large unit which was used in a radio station for cleaning audio from their logging tapes. Plus of course there's the long Wand used to degauze coloured cathode ray TV screens. Oh yes and a smaller unit for cleaning cassette tapes in compact and 8 track formats. I guess we shouldn't forget the small erase heads in all Tape type recorders, both audio and video. I also purchased a dumb unit from BangGood which has a plastic enclosure with a magnet sealed inside. It had holes on one side to Magnetize your screwdrivers and holes on the other side to demagnetize them. Not very good sadly, I much prefer the large audio unit for tools. Great videos mate, all the best from downunder.
propfella Also can be used to destroy HDD.
WOW, I never knew that, next thing you'll be telling me they also wreck floppy disks, yer right :-)
I was trying to look up some of your vlogs on some of your kit building,when the power supply kit ,I am building gave me a problem,I am sure you have Had a foil u were scolding come off,what did you do to complete to the circuit,did you make a jumper,or scratch off some more foil to make a jumper,I thought I would ask a expert.some of these Chinese kits have been a little hard no that I am older and the kits are so small. The kit I am trying to build is a LM 317 power supply, maybe it a kit you have already done,thanks for all your videos.
When degaussing tape heads, you would get the degausser, touch the tape head and move it away in a spiral motion.
i had to use one of these on my 21" crt tv back in the day , because i left a hifi speaker close by 😀😀😀😀
I have one of those old bulk tape erasers from Radio Shack, I haven't tried it, I wonder if that would work too?
I normally just wack screwdrivers on something, and that works pretty well for me
You can also use this if you have a mechanical watch and manage to magnetize it.
just used this very model to demagnetize the main spring in my automatic watch
It's great because it's so cheap you don't really care if you use it once or twice and then it stays stored in the garage since you really don't have your watch magnetized very often
I wonder what the ideal timings are- one could hack in a demagnetize button maybe?
wow man that's amazing
here in 2020 you legend
Add an extra button with a diode in series and you have a magnitizer and de-magnitizer in one.
I use this to demagnetise my watches works well
thank you so much :))
Whatif you put an inline dimmer switch/pot and slowly turned it down. You could get one of those clever slider types from the home store.
nope they chop up the ac waveform, not reduce it 'linearly'..
There is linear potentiometers
Or just use a variac - we know Clive has one of those...
Your typical aquarium air pump uses an E-Core, could maybe make one of my own.
Thanks for that :-)
Maybe the wire had the slight magnetic field after being in contact with the magnet?
Reminded me of demagnetizing audio casette players. Got to move the widget away very slowly for first few centimetres, but that wouldn't thrill us viewers here :)
It is also installed in battleships because all the electric stuff can magnetize the hull making them point north. Think 6 pair (all twisted in a cable, helix) of 500 mcm wire pulled around the entire hull of a destroyer. This is often what confuses dimwits into thinking the Philadelphia Experiment is reality. Degassing is common in large magnetic structures.
Clive, when we put a magnet near the screen of a CRT, why does the effect persist? What is being magnetized. I thought it was just glass and a phosphor coating. Does the phosphor coating have grains that get re-arranged or something?
+Derrick Blackburn There's a metal shadow-mask behind that makes sure each electron gun only hits its specific colour of phosphor. The residual magnetic field can be removed with either an external or built-in degausser.
Must look to see if I still have one fish tank air pump, which uses the same coil. Comes with a case as well and a cord, though I would have to put in the switch. That unit looks remarkably similar to the fish tank pump housings as well, probably made by the same factory.
SeanBZA Careful - without anything to complete the magnetic circuit the inductance will be a lot less and it'll get quite hot very quickly. If it's got a one-shot thermal safety cut-out embedded in the winding you'll only get one go at finding out how quickly.
A core designed to go in a demagnetiser will be wound differently, although it'll still only be rated for intermittent use.
Graham Langley It is open, with only a ferrite magnet waving in the breeze....... They did look very crispy though after a few years moving that rubber diaphragm though. not helped by them all seemingly to be made with the core cover being ordinary painters masking tape. That almost always was a few brown crumbles inside the bottom of the rubber base when you opened it, along with the black rubber crumb from the pump diaphragm falling to bits.
SeanBZA My baby degausser is the coil from a defunct hair trimmer. It's an E-core and drove a magnet that oscillated back and forth between the open legs of the core - there wasn't much coupling. But without it 30 seconds is as long I reckon it's safe to run it for.
Try moving the whole part sideways through the field and away slowly.
once I put a neodymium magnet on an old TV and the psychedelic patterns pretty cool
DO NOT DO THIS ON YOUR MAIN TV
if you have a CRT television
AKA a tube TV
I presume you can also use this to remagnetized your demagnetized screwdriver?
Thank you
hows the weather on the island tday? any sign of racing?
I wonder if you could use one of those big clunky wall adapters to degauss something
They don't tend to leak enough magnetic field to be useful for that.