Faulty Plasma Cutters - Follow-Up Video (With Thermal Camera) | Will It Catch Fire??? 

*** UPDATE *** Since recording this, a few people suggested increasing the resistance of the resistors I fitted. I added another 2.2K to make a total of around 16.9K in parallel with the NTC sensor. Everything now works as it should. If the sensor becomes unplugged or goes open circuit it shows error E04, I've had the temperature down to -8C and the unit still operates as it should, the fans still kick in around 30C, and the over temperature protection still works too. So if anyone else has this problem around 17K resistance in parallel with the NTC will fix it. Thank you to everyone who suggested increasing the resistance slightly. imgur.com/a/39xpsuO

I would be very happy to use this machine without concern. In fact, it's far safer now than when it left the factory. One of the problems with youtube, full of sofa experts!!

It's amazing how many people don't know basic circuit analysis, but they're experts in the comments section!

Thank you for answering peoples questions and your clarification of what you have done. Great fix once again

It cracks me up when you get all these RU-vid engineers out there that know more than anyone else does. Google University must be full of these idiots. Not only did you solve the problem with the plasma cutter, you also educated a few self righteous know-it-alls!! Excellent work Mick.

I'd argue using a slightly higher resistance (value) than the shutoff-point would be better since that would allow the machine to still detect when the plug disconnects itself again. Putting them on the PCB was the least intrusive and easiest to reverse - and so the most sensible way to see how the system functions normally. (But) I'd have been inclined to put the resistor(s) in parallel on the wires so that the plug disconnecting would still be detected -- avoiding the situation where the thermal protection _becomes_ bypassed if the (mismatched connector) fails again. AND/OR trying to find the exact value of resistor...

You absolutely don't need to readdress this because of certain comments. However the fact that you did and explain and demonstrated why and how maybe enables others to understand the circuit a lot better. So you actually taught some that didn't know or understand...now they do... Thumbs Up!

Isn't an expert just somebody that has little cards printed that say they are an expert? I'd rather have you work on any of my electrical equipment than any self proclaimed 'expert' who lacks the attention to detail you have. Thanks for the interesting video again!

As an electronic engineer nice explanation :) Fair play for revisiting.

With the parallel resistors you just created a basline for the controller to work with, as you have shown, it switches off the active cooling when it's cold enough without the fan running, and still blocks operation if it senses too much heat! "All good!" as a famous australian drain cleaner would say... 😂👍

I always love how these "armchair experts" love to confidently (incorrectly) tell people they're wrong. lol You did exactly what I would have done. If anything it's probably (very slightly) lowered the high temp threshold. Good work!

I was not confused as others were, but I have taken circuit analysis. You explained it perfectly, and it made perfect sense in the previous video.

Yes , You was right to set it parallel to the NTC , if it's hot the resist falls very low in Ohms , so that parallel resister in the range of KOhms has no effect on the shutdown function

One thing the trolls managed to do was to get you a whole new video out of a well-done repair. Trolls can have a purpose I guess.

Yet again, keyboard electronic experts proved wrong again. 😂

Just when I thought I couldn't like your videos more, you do such a clever demo. 11/10 repair. Thank you for sharing sir!

I'd still put the resistor betveen sensor wires, just to E04 to be able to show loose connector. I'm not convinced by compatiblity/quality of those connectors, even if the are glue together. Nice dignosing and fix although.

I think what most people are referring to (at least I hope so), is that you disabled the units ability to detect if the sensor comes unplugged or fails open. This may lead to a dangerous situation where the unit will happily keep trucking along without a working temperature sensor potentially overheating. At the same time, it is also not possible to wire resistors in series as this will cause the temperature set points to become skewed, causing the entire temperature monitoring function to not work at all. The correct fix would be to modify the programming to change the 15Kohm "open circuit" detection to something more sensible, but that will obviously be difficult to do. Or you could use a slightly higher resistance (16-18k or something?), so the unit still detects if the sensor is open circuit (unplugged/failed open).

It’s great that it worked well, though it was a shot in the dark. It is right to question this approach as taking a chance is not the way to go and proof testing should always be done afterwards to make sure it works within its intended limits. The people that were happy to use it without it being tested would also be happy for their mechanic to replace their car brakes with random bolts and parts too right?

Resistance in paralell is lower, in series they add together. So it will cut out faster (at lower temp) when in paralell. Formula to calculate resistance in paralell would be 1/R(t) = 1/R(1) + 1/R(2). Keep in mind that if the termistor dies (open circuit) you will no longer have over heating protection, so its best to increase the value of the resistor slightly so it will cut out if your thermistor goes open circuit.

Parallel is correct ... but ... you also have to take into account that if you ( for example ) put 2 x 1/4W 10K resistors in parallel, it becomes a 1/2W 5K resistor array.

maybe i misunderstood what you did in the original video, it sounded like you said you added the resistor in parallel and thus the resistance would never go close to zero, which of course is wrong and probably why you got so many comments. anyway, so long as it works you did it right, whatever you said.

The only reason I would have soldered the resistors on the wire side instead of board side is that both units showed tendency towards plug mechanicly displacing themselves from the plug. Putting the parallel resistors near the thermister allows for safe service stop for both plug disconnect and most of wire breakage. Just discovered your channel today! Please note, my comment is not ment to denergrate your solution. But my years of experience fighting Mr.Murphy's Law says to put fix by thermister! Hopefully, you folks across the pond know of Mr. Murphy! I like what I have seen of your channel, and you have my subscription! Hopefully, you can inspire a few youngin's of Today to become tinkerers and fixers of our throw aways! Semper Fidelis Bob

Absolutely love this. Just what i wanted from the previous video. Dialogue and questions are what education is all about. As long as people are respectful and genuinely engage then it should be encouraged. Thats what makes great content and you make great content.

To be totally safe you would need to calculate what the junction temperature of the power devices are. And check it th3 the max limit, as a 100 deg C heatsink may be too high. I would also check the earthing and make sure it conforms to the LVD. If its anything like the K40 laser i brought from a uk supplier it was a death trap. I feel a lot better if it goes back in a safer state than it did when it arrived.

Hehe my daughter saw me watching the last one and I quite liked the idea of a plasma cutter here and she had me wallet away in a second and admonishing finger waggling and nag muscles set to stun "no father you ARE not having one..." :( She's a bit fed up as her old bedroom is now a very crowded area half full of watches (700+ in the collection O.o) and half full of a workbench with pillar drill, 1930's Portass lathe, gasless mig, 3d printer, a plethora of power tools and boxes of stuff for polishing, cutting oh and a 1960's Italian Aspire engine (Tecumseh knockoff) oh and my large compressor, air tools etc... I have just finished refurbishing a Snap On air impact gun which had the local post office questioning me whether it was a naughty naughty gun not an air tool hehe I made a joke showing it to my postie lady that she wasn't equipped with any nuts I could be taking off with it, made her laugh all day she told me :P I did forget to mention front room is stacked with about 20 games consoles, several feet high many stacks of games for consoles, a 1958 Lambretta Li150 and a 1985 Vespa T5 and all my steam engines including a verra rare 1939 Mamod SC3 all original in its original box and accessories, only made for 3 months before WW2 started Mamod said about 100 were actually made... rare as rocking horse bollo... droppings :D

And ….a healthy dose of theory, coupled with proof of concept experiments, thrown in as a bonus vid !? 😱.It doesn’t get any better than this.🙏🏼

I'm sure somebody already said this, but according to Ohms Law parallel resistance is calculated as Rt=1/R+1/R+1/Rn... so in this example at high heat and taking 10 Ohms as the thermal probe value the resulting total resistance would be calculated at 9.96 Ohms. within the range to throw a high temp error. His explanation, while a bit simplistic is sufficient.

When I saw the thumbnail of the cutter engulfed in flames I thought” … there’s no way!!!! That was some excellent graphics work with the “fire”. It did exactly what it was designed to do. Made your fans say”…there’s no way!” and your detractors say”…🎉 see, I told you so!” And made all of us watch the video. Your RU-vid skills are quickly catching up go all your others. Thanks for the video, they’re great as ever.

Thanks for the follow up video and kind words regarding my surgery. Some folks speak too soon but learn quickly when listening closely😉 Great fix of course, well done.

I've owned not one but four and yeah I have absolutely positively fucked-up a few Parkside (Lidl) plasma cutters in my time. These cheap inverter-style plasma cutters and welders are handy for short jobs, but suffer from short duty-cycles and as a result rely heavily upon multiple thermal protections to prevent spectacular meltdowns. Take it from me, they can go tits up quickly with a seriously loud audible notification! 😉

Thought i was seeing things when i got a notification you uploaded midweek. Wish you would do more than one a week but with your incredible talent im guessing you are kept busy. Thanks for the great content.

The haters always hate their betters Dude. Stick it to them..

Thanks, I initially had to think through it, but the key to understanding the fix was the NTC which was key and understanding parallel resistors which you explained very well. Only issue now is if it opens up no one will know but hey cheap free China junk at this point. Good fix!!!

Does not matter. As long as your animals are safe 🙂

hi I agree with you. finally, someone that understands that you can't measure the temperature of something reflective!

Appreciate the follow-up, but really, that extra parallel resistance should have been a bit higher - 22k would have allowed the open-circuit detection to still work if the thermistor failed open circuit or the plug came out again. Using 15k stops the unit detecting open circuit at all.

Great explanation and it does make sense! There's no risk in this mod imho, and I believe it's now more fit for purpose than it was from factory!

And yes, negative things are always a problem ;) (ntc vs ptc, npn vs pnp ...) I did not misunderstand, but it's cool you make it clear for everyone with simple but concrete experiment ^^

yes that's right

Good data! Good video! Very satisfying conclusion!

Just a great fix you dont need to explain to others just make your videos. But if you like to explain them no problem. Have a nice day🎉

Well done sir - it’s a shame you had to prove people who don’t understand what you did. Keep up the good work I love your channel

Spot on Mick, I’d trust you in anything you say as everything you do is educational and well explained, just shows that college degrees don’t beat experience 😊

Thankyou for taking the time to test the modified circuit.

Great job.

Awesome ! I think it's wise to draw it out like that to fully understand before making a fool of yourself in the comments !

Excellent. Now all you need (for the failed open scenario) is an Arduino monitoring current into the thermistor or wrap one of the thermistor wires around a reed which is in series with your resistor mod. Both super-easy mods, if only in my head, ho, ho.

9:25 oh don't worry, the only thing you burned down is the people who thought they knew it 😂 Keep it up brother 💪 you know what you are doing :)

Very good! Thanks.

The safety trolls are having a freak-out. You have to be careful about feeding the trolls. They're hungry all the time.

Perfect explanation! I was also curious how your resistors fixed it. Now I understand. Brilliant! ❤

Good explanation thanks for the info

You’re totally right and explained it well.

@ 5.54.....what can't you hear ? 🤣 Great vid btw

The commenters are incorrect. You are dealing with Facebook experts, not reality in this venue. You did exactly what the mfgr wold have done to sole this issue.

I never doubted you. Great job.

Quality follow-up video and demonstrating it as well.

I think you proved it all first time.!

If I may be so bold as to suggest it, I think some of the confusion stems from time stamp 34:03 in the original video where you said "resistance can't go below" when I think you meant "resistance can't go above", and the same thing at timestamp 8:25 in the followup video where you again said "drop below that" although in that second instance I think perhaps you were meaning the temperature not the resistance?. Both times when I heard it I said to myself "eh, what?". Didn't comment first time round, couldn't "resist" this time :)

With that plastic hose inside, run it on argoshield or better. It'll cool it down, like a fridge . Helium could be even better😅 and a good laugh . Does say argon on the cover

Great job now you ever confirmed the correct operation so there is no doubt it will perform as intended. Good Video as Always..!!

Well done and well explained, sir!

Best channel on RU-vid

Not sure if you will get to read this, but still... The only problem with the units is that the temperature thresholds are unfit for UK climate ( and other countries with cold climate ), that is a dumb thing but they are China stuff so... Who ever said that the mods should have been in series with the NTC should really read about Ohm's laws and about how an NTC works! When you did the mod you lowered the overheating threshold because as the NTC heats up it's resistance lowers and that is just what you did, lowered the NTC's resistance ant room temperature, meaning the overheating protection comes at a lower temperature now. As i said, people should learn basic electronics, like Ohm's laws, and basic components and paralleled and series resistance, and stuff. You did go slightly wrong on the mods, but not on the configuration ( putting the resistors in parallel with the NTC was the only way to go ), but rather on the values chosen. You really need to make sure the mcu still reads when the NTC is disconnected, because it can happen and when it does, everything temperature related will be off, and the unit will no doubt fail quite spectacularly! What needs to be done is lowering the threshold at which the "NTC disconnected" protection comes in, without nullifying it completely. This is done by trial and error way, your mod is fine, just it's value needs adjustment, until you reach a point where that protection still comes in but at a lower temperature threshold ( say 0*C for example ), without compromising the overheating threshold, which must be checked each time a mod value change is done. The way i see it, i think the mod value should be a larger resistor, you use the same pot in parallel with the NTC ( while the NTC is mounted on that smaller heatsink ), and everything connected to the board, and the unit powered on, you adjust the pot value until you see that the "NTC disconnected" protection comes in at somewhere below 5*C ( i think that would be just fine ), then you check the overheating threshold, making sure it is still ok. You do not want the overheating protection to come in too soon, you cannot do any work that way, but it should not be so high as the heatsink starts smoking, somewhere between 80 to 100*C should be just fine ( also you should check at what threshold the fans starts ).

My question is, why didnt you out across the plug on the leads side? These units seem to have an unplugging issue. If the temp sensor lead becomes unplugged, the unit will still work, no? And then, without the sensor being plugged in, the unit could overheat. It you put it on the leads, at the base of the plug, and it became unplugged again, you would know and the safety system would work as designed. I think its a great fix, but I think not putting it on the wire side, can cause potential danger because it can still operate when overheating. I could be wrong, but am I? I could be mistaken, but i thought it ran without the leads being connected in other video.

Nice, i dig the new thermal camera. That will be my next purchase. Especially since i see paranormal channels use them and with interesting results. (Ghosts or bigfoot) Excellent test results. Perfect proof of concept.

Well explained, Mick. I knew you couldn't let the comments go on. I too would have done the same. Thanks for sharing.

Fun to watch both videos. Nice job.

People with zero knowledge of resistance in series vs parallel connection questioning an experienced person's repair with confidence of PhD in electronics.

*Thanks* for the Test.

Great explanation mate. Right one. Cheers

Great job done😊

I'm guessing if the RTS becomes unplugged again both the high and low cut outs as well as the RTS disconnected error won't be triggered? But then you have glued the plug.

How dare people doubt you! 😂

Bush Barbie says there are people on this planet that shouldn't be. I know she is right. Keyboard experts are usually wrong and nothing lost if you pay no attention to them. For fun, I look at their channel and they usually don't have any content. As always, comprehensive video and spot on...!

It only worked because the sensor lowers it's resistance to almost 0 with rising temperature, right?

Thanks for this

Incredible that after all your skilled repairvideos, you still get these comments 😂

08:04 Resistance isn't futile🤣🤣🤣🤣 🖖🖖🖖

Do you consider this to be fixing a design fault or a build fault? Could it have been a tolerance fault with the NTC resistor? How is the temperature sensor measured? If an AtoD on a processor, the manufacture could have fixed the fault with a corrected software setting, as the error messages indicate a window detection function. It would have been informative to measure the voltage across the NTC with temperature, as this would have indicated what the processor was measuring. The NTC resistor is likely part of a resistive devider network, with either the NTC resistor or its associate fixed resistor referenced to circuit zero volts. While the fix clearly works, it might be masking the real fault in the A/D circuit. The incorrect connector might indicate that the NTC resistor was from a different component supplier and maybe had a different characteristic. It is impressive that you managed to locate the problem with so little information, not even a circuit diagram, something you manage to do in other product fixes. While the fix solved the problem, which maybe all that matters, it might not be the real source of the problem, which could be a design fault, a component tolerance spread problem, a component supply problem, a software setting problem (perhaps in manufacturing alignment) or a build fault with the sensor associate resistor or its power source. It could even be with the A/D voltage reference. Even with such a poor build quality, it might be unwise to assume such a simple design fault as not accounting for a low temperature operating environment. These units are likely made in volume, so such a design fault would prove very expensive.

Had to look twice. Thought you new camera had a milf setting not mlf 😂

Does it still sense the sensor being unhooked? That is my fear. It gets unhooked and goes to a base reading and can keep running till it over heats?

you made the classic mistake , of putting the heatsink on a yellow brick and not a red engineering brick ,this could have caused a worm hole to open ,causing a tear in the space-time continuum , and the complete destruction of the known universe as we know it .rookie mistake lol :P nice job :)

Hi, with this setup with it give the thermistor disconnected error code?

Hi Loved these videos so much I went out and bought a faulty Plasmargon PLC55. Very much hoped it would have the same fault.....nope! This one is completely dead. No lights on main switch or panel, no fan etc. There is A/C power to the relay. If I apply 24V to the coil of the relay with the bridge rectifier DC wires disconnected, then I can hear the relay click. If I do the same thing with the bridge rectifier connected, then the mains RCD gets tripped. I take it there is a short somewhere, any pointer of where to start looking, please? Kind regards Rob

Hi, if you connected the resistor in paralel on the sensor cable instead on board it would work same but it would also throw an error code when you disconected the probe from the board or am I wrong ?

There is one issue left though. Adding the 14K7 disables the missing NTC detection because the uC always sees the 14K7 resistance and not the infinite resistance of a missing NTC. So if the NTC goes bad no error message (E01 was it?) will be displayed, effectively not detecting a posible overheating and shutdown of the device. Or is there an other overheating cut out in place?

Sounds like they fitted the wrong NTC from factory...

Adding resistors ONLY sets a low temp point and did not affect the high temp point.

send this video link to the seller

So they're worried about a fire while cutting things with fire or plasma. Got it.

5:54 excellent impression of a plasma cutter, or maybe a dolphin...🤣🤣🤣 To be read in the most nerdy whingy voice you can imaging... "Dear Mick, if that even is your real name, this is a sloppy explanation/demonstration at best. To really real world test your hypothesis you should have spent several days cutting out the pieces for and assembling a trike, or motorcycle of some sort. Only then would your testing have been in any way believable. The manor in which you tested is of little to no value as, for all we know, you could have rigged the results, or used camera trickery..." 🤣🤣🤣🤣🤣🤣 Bloody keyboard warriors, they've probably never even used a soldering iron in anger. Christ on a bike, you couldn't take a p1ss on the internet without some tw4t jumping all over ya, telling you your doing it wrong... Keep up the excellent work, you're content is brilliant!!! Ignore the detractors. Not to be confused with how your neighbours would say the tractors, as in "hey up, der go detractors inta field son" 🤣🤣🤣🤣

My worry is that if the temp sensor plug manages to work itself free again, the resistors you've added will make the cutter think the temperature is fine even if it is overheating.

Makes me wonder how many of those people who said you do it wrong or it could start a fire have actually got electrical engbineering certificates or have been college to learn all of that stuff. Perhaps they just have the ability to change a 3 pin plug and hope they dont blow a fuse afterwards.

In reply to my previous video comment "Resistance in parallel will not work." Ohms law is "the total resistance in parallel will always be less than the smallest resistor." This was based on your wrong answer in the comment section in reply to @nickalexander6773 "The resistors just stop it dropping lower then 15k" and your wrong comment in the video saying "The minimum it likes is 15K" ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2wt5Y-lyqO0.html Beside you being a great source for entertainment you also provide a great source for learning, By providing wrong explanation how it works you mislead your viewers, anyhow you seems to understand it fully now🙂 By disconnecting the too cold protection with the resistor, condensation will occur when used in cold environments, and the cutter will short. Maybe it was nothing wrong with it at all? Can it be that the user have tried to use it in cold environment?

Can't fix stupid. You mentioned quite clearly that your mod affects the bottom end of the temperature curve, not the top end. Nowt wrong with them. Now.

How embarassing, accusing someone of making a device dangerous and being so utterly wrong! They probably voted for Labour too, lol

Perfect explanation as always... brilliant