Does anyone know the exact legal regulations on non fused transformer primaries in various countries?

@N3szt0r

5 жыл бұрын

Eu: all mains products have to be primary fused. However chinese products offen are findable

@daveturner5305

5 жыл бұрын

True but in the EU, if I remeber the regs correctly, that is to protect the 'house' wiring; not the unit plugged in!

@sofa-lofa4241

5 жыл бұрын

UK consumer electronics regulation 374628/8467-6 subsection 6c paragraph II, clearly states 'Don't let that crazy Aussie bloke plug it in, it makes the pixies mad and you just know that sh*ts gonna happen!'

@Pops180

5 жыл бұрын

I dont believe it's a regulation. From what I read, the over current protection is handled where the power comes in (circuit breakers). Only exception is when RMS voltages over 1000 are brought in. Did the circuit breaker in your building not trip? 220/0.2Ohm is 1100A. The breaker should've popped. It also mentions cord length. So maybe if the cord is short enough, you dont need a primary fuse. I guess it's just a shitty way to gaurantee some repeat buys

@vcr32

5 жыл бұрын

Dave, I think maybe this was an assembly error. It's possible the fuse is supposed to go on the primary, with the polyswitch on the secondary. Having both in series seems a bit strange after all!

If this were Big Clive he'd plug it back into 240v and see how long the smoke lasts.

@qwertyasdf66

5 жыл бұрын

That's exactly what i thought the thumbnail was, and i waited the whole video for it.

@gavincurtis

5 жыл бұрын

Then take a deep whiff of it and gag off camera.... did you see the one wher he did that with the fart smell generator? He took a whiff of the concentrate and nearly collapsed...poor guy. Clive is awesome!

@ernieschatz3783

5 жыл бұрын

Electroboom would have broken out the marsh mellows after testing the temp with this tongue

@paulstubbs7678

5 жыл бұрын

Nah, give it to Photonicinduction, he'd wind it up to 600V

@SuperStststststst

4 жыл бұрын

nice

This was totally caused by core saturation, turning the primary from an inductor to a resistor. It would be more expensive to have enough metal to tolerate a 2x overload. Hard to see how it can comply with safety standards to have a 10A capable input connector and no internal fusing. A primary short could potentially dissapate a kilowatt - this has to be a recall-level design flaw. Would be interesting to compare the 230V version.

@EEVblog

5 жыл бұрын

Does anyone know the legal regulations on this?

@tomvleeuwen

5 жыл бұрын

@@EEVblog We once had a floating neutral on our company power net due to a faulty main switch, resulting in 380v between one phase and the neutral instead of 230v (assuming worst case, I was not there to measure). This issue basically blew out ALL the transformers that were connected. Only one catched fire, luckely it was outside, but all of them were broken. I later leaned that it is allowed to malfunction but not to catch fire (as long as it is properly fused), at least in the EU.

@AJB2K3

5 жыл бұрын

@@tomvleeuwen I remember a customer had a neutral fail on a 3 phase farm. 480v across a 240v system distroyed everything plugged in including the house wiring.

@ald3nt3

5 жыл бұрын

Could saturation also kick in due to 50hz mains on a transformer designed for 60hz?

@mikeselectricstuff

5 жыл бұрын

That certainly wouldn't help.

Dave get a 240V transformer that fits in there and fix it! Would love to see a repair video!

@skuula

5 жыл бұрын

Yeah, 24V secondaries are very common, shouldn't be hard to find one.

@locouk

5 жыл бұрын

Manu _ I was thinking along the same lines, could a salvage MOT be used stead?

@SteveBrace

5 жыл бұрын

I reckon Weller will send a complimentary replacement within a week :)

@Basement-Science

5 жыл бұрын

Green Silver a rewound MOT would be way too big, but in theory, sure.

@JustinAlexanderBell

5 жыл бұрын

This thing will smell so bad after that, doubt he wants it around.

The activity you thought you saw on the LCD - it was the letters H E L, and P. =D

@robbieaussievic

5 жыл бұрын

..... Yeah, I was thinking 'OUCH !'

@camelCased

5 жыл бұрын

SOS

@StaticVapour590

5 жыл бұрын

It's made by Weller, so it showed "WELP" on the screen

@musashi939

5 жыл бұрын

@@StaticVapour590 haha. Came for the video. Stayed for a the comments. Bloody good

@68MalKontent

5 жыл бұрын

Probably it was flashing, because the polyfuse kicked in (and out) several times, until the normal fuse finally blew.

I have designed many transformers and the 'window' of operation is surprisingly small. You basically select a core that meets your power requirements and add a bit (but not much due to size and cost). You then calculate the primary turns required to avoid saturating the core (which is why 50hz and 60hz transformers generally have different sized cores) and the wire size to carry the expected current. The operating range has to take into account the acceptable range of secondary output voltages and in the UK, for example, we have mains voltages varying from 210V up to over 250V so this has a major bearing on the design limits. The outcome of allowing for all variables is a transformer that will generally run into core saturation much beyond the design voltage and at that point it acts like a very low value resistor and soon after that the turns start to short and that causes shorted turn heating so the failure mode is very rapid. The basic safety directive dictates that users should be allowed to blow the crap out of it as long as nothing becomes live and as long as it cannot catch fire (flames, not smoke). Once enough turns have shorted the mains fuse will blow.I think that more recent directives have differing standards for smoke hazards as opposed to electrical safety.

@Moonlightshadow-lq4fr

5 ай бұрын

I have a 120 volt variac/autotransformer, is it possible to use on 240 if I put a lightbulb in series with the variac. I know the voltage will be the same but will it still over saturate the core?

They should have put an MOV across the primary terminals, and a fuse in line. My Astron RS35A received 240V when the neutral was broken. This drew 240 across the plugs, when high load appliances (Aid conditioner) in the other phase brought the now isolated neutral to the potential of the other phase. My astron belched our some pretty nasty smoke. Opened the unit, the MOV was nice and crunchy and the once clear glass fuse was black as the ace of spades, but the transformer was fine. Changed the MOV and fuse and put it back into service.

@davidgriffin79

5 жыл бұрын

Just like mechanical engineering, electronic engineering is just so incestuous (relatively small circle of people who know everybody else).

@BruceNitroxpro

5 жыл бұрын

12voltvids, Fabulous... I will retrofit my new RS35M before mystery smoke does any danger to it.

@ernieschatz3783

5 жыл бұрын

When he described the magic smoke and explained the cause, I immediately though he'd find a crispy-black MOV. I was in a state of disbelief when he opened the cover...like "there's got to be an MOV hiding in there somewhere."

@MrJohnnaz

5 жыл бұрын

Had the same thing happen on a microwave oven, the duplex outlet that it was plugged into had some internal issues, that caused the micro to see 240V as it was on a split circuit. Replaced the MOV and the fuse and it is still in service 10+ years later.

I had a Weller WTCPT (220V) which I bought decades ago in Europe. When I moved to the US, I contacted Weller, for a possible suitable transformer, and they provided me with a replacement transformer to use it in the US, for a reasonable price...

Regardless of regulation I would expect Weller to spend an extra 25 cents for a fused IEC connector and a properly sized fuse. It would have prevented all this damage from even occurring. The transformer saturated without a doubt and this caused the impedance of the primary to drop significantly which in turn caused the transformer to draw excessive current and burn the enamel on the windings. Had there been a fuse say 5A or whatever it would have blown as soon as the transformer turned on and saturated. The transformer would still be in perfect working condition. The design is unacceptable.

@Bulmaimi

2 жыл бұрын

I just did the same mistake and burnt my brand new Weller

I myself experienced some magic smoke from an film capacitor of an old vcr. It was unfortunately opened when it happened and so it was shooting smoke at the ceiling like some firework. Took hours to get rid of the smoke smell. I was lucky enough to not have my head over the vcr when it happened. It literally took place 3 seconds after I studied the circuit board with my head obviously over the bloody thing while plugged in.

That product was never tested for use outside of North America, due to it only having a UL Listing for US & Canada (cULus graphic symbol) and no certification marks for any other country safety testing organizations (i.e. AUS, RCM, CE, etc). That product was evaluated by UL under File Number E18708 for Apex Tool Group (aka Weller Professional Tools Division) to the UL Category "KQLR" - Industrial and Laboratory Heaters, which uses UL Standard ANSI/UL499 and ANSI/NFPA 70 (aka National Electrical Code) to evaluate the product. This particular product category does not require additional fusing of the product primary power input, and relies entirely on the branch circuit power protection at the main power panel of the facility.

@BruceNitroxpro

5 жыл бұрын

KCautodoctor, A sad but true fact... and a cautionary note for people buying in NA.

@stragulus

5 жыл бұрын

Shouldn't that at least imply that it cannot be sold as a consumer product?

@KCautodoctor

5 жыл бұрын

@stragulus not at all. Check out all the other consumer level soldering models that Weller sells that have been evaluated under the same UL FIle Number E18708 for the same UL Category "KQLR" - Industrial and Laboratory Heaters

@stragulus

5 жыл бұрын

@@KCautodoctor Thanks for that. I guess what I'm asking is, is the intent of that UL category for devices used in labs, instead of consumer homes, and are they abusing this category?

@KCautodoctor

5 жыл бұрын

@stragulus that is a common misunderstanding when people see the names UL uses for the category descriptions. It is a carry over from many years ago and no one wants to change the category descriptions since it will lead to more questions about why there was a need for the change (i.e. lawsuits, etc). If the product is UL Listed but was never evaluated for use by an average everyday consumer (a typical Walmart or Home Deport type customer) but rather intended to only be used by a trained professional, then it will include wording near the UL Listing mark that the product is not intended for consumer / home use. UL has the final say on which category a product will be evaluated under based on many factors, including who the customer / end-user will most likely be.

I once got a call to fix electrics at construction site. The lights were not working, and a little refrigator was "walking" when plugged in. Problem was that someone before me had connected neutral to 230V making the sockets and lights run at 400V. The compressor of the refrigator was running so hard, it made the refrigator vibrate enough to make it move :)

I remember my PEBKAC very well. Quick late night repair on small motor driver system.I didn't pay attention when hooking up the new transformer and I switched primary and secondary. Reached over my bench to plug it in ...... Sometimes I still see the flash or feel the bang in my dreams. Luckily we all learn from our mistakes.

at least the ripoff hakko is fused!

@mattmoreira210

5 жыл бұрын

Jorno they copied it right where it matters

The 120V FX-888D throws its primary fuse the moment you give it 240V. Shame Weller didn't fit one I suppose. The 888D fuse is unhelpfully soldered onto the board, which is awkward to fix if it's your only iron!

Back in the 80's I watched an entire rack of audio power amps go up in smoke when the electrician wired the stage power distribution to a high leg 3-phase source. Keep in mind this was the days of amps with huge transformers and even bigger capacitors. Well about 3 seconds after the power was switched on most of the caps burst creating a miniature version of 'Towering Inferno". While I wasn't responsible for the power on that day, I made a rule to ALWAYS meter the power before connecting any equipment to it regardless of how safe you think it is. To this day, even though 90% equipment is universal voltage, I meter the power before connecting my equipment to it.

lol, my first station was the Weller WES51D bought from US, so 120V version. My mains are 220V and i was as naive as an excited kitty. So I plugged the station to mains as soon as I unboxed the station and was watching it heat up, suddenly a big bang and all gone dark. Later found that the primary coil was blown. The WES51 is a low wattage station, so luckily in my case, the primary coil of its transformer had finer gauge than the 1010, which lead the coil winding to be blown and then disconnected from the mains in case of the overload. This protected rest of the station from being damaged. Later, I replaced the original transformer with a local made dodgy 220V compatible transformer which is still working flawlessly for 3 years now.

@shkhamd

5 жыл бұрын

Later I bought the WD-1 from alliexpress and to my surprise, I found that the seller already modded the original station to be compatible with 220V by replacing the original 120V transformer. I never been happier with a station than that. Recently I bought this 1010 120V station for another official purpose, but this time I triple checked by my first plugging in with a 220V to 120V step down converter. Expensive experience for lifetime for a guy like me, lol

Had a similar experience when I worked in a computer store. We ordered a power supply for an hp that didn't fit any regular off the shelf power supply. so we shipped one in from a supplier in the US. When I ordered I checked if it was rated correctly, and it was. It just happened to be one of those where you have to manually change a small red switch at the back. and by the time it arrived I'd completely forgotten about the fact that it was manually switched, and that it came out of the US so i should at least have checked it. as soon as I plugged it in all caps from the psu started venting filling the store with chemical vape. after unplugging it, I immediately realised what went wrong and wanted to dig a hole in to the floor to hide my head from my laughing coworkers. that capacitor smell though made me nauseous for a while. spend quite a few days trying to vent it out of our office.

@anttimaki8188

5 жыл бұрын

I did similar when i was a kid. My big bro had a new 486, and it had this intresting red switch on the back. Click, and sounds/smells started. I got in a bit of trouble aswell. Fortunately the computer seller was understanding, and gave a new one with the nasty red switch glued over.

@Rightclick88

5 жыл бұрын

@@anttimaki8188 yeah exactly , fortunately for me only the power supply was destroyed, the computer that belonged to a customer was fine apart from needing a good cleanup. we made no profit on that particular customer, but that still better than having to repair the whole pc at our own expense.

@Karreth

5 жыл бұрын

Yeah, I've done that too. I was 18.

@saddle1940

5 жыл бұрын

Kids do that at schools all the time. They value and treat the PCs with twice the respect they paid for them. Since they were free (to them), well.....

@catsbyondrepair

5 жыл бұрын

Dumbass did what lols

Small mains transformers like this are designed to operate just starting to saturate even at proper voltage. You can observe this by monitoring the current waveform using an isolated scope probe across a low value resistor in series with the primary leads. The wave form gets "spikey" as you turn up the voltage closer to mains level. This is done to allow the minimum number of turns to keep copper losses down for better load regulation and to use the minimum amount of iron core material.

@EEVblog

5 жыл бұрын

That would be interesting to investigate.

@WarpRadio

5 жыл бұрын

"Billion" brand transformers are known for this.. they usually burn out quickly (short service life) even at rated voltage!

@foobarables

5 жыл бұрын

Completely agree on that. Saving money on iron and copper leaves no room for even small over voltages.

@MrDoboz

5 жыл бұрын

@@foobarables yeah, that was what I was thinking too :P

@laharl2k

5 жыл бұрын

So in summary they play with the fact that the transformer will most likely always have some load from the soldering iron to avoid saturation, much like micrwave oven transformers?

Hey Dave, Thank you for this video. This is actualy the reason I didn't buy a Weller. I made a video what soldering station I have now purchased and of course mentioned you! Have a great day!

In the mid 1970's TI made a thermal printer for the SR52 and SR56 calculators. This had a full wave rectifier, with a center tapped transformer. The fuse was on the center tap of the transformer, with no fuse on the primary. They used 1N4004 diodes for the rectifier. A common failure mode for these would form a short. Once one diode shorted, it would overload the others, causing them to short. The PCB would actually catch on fire after this. I worked the the repair center at the time. and saw a lot of these units. I saw a few where the transformer got so hot that the plastic case started to melt. We had to modify these to add a fuse on the primary. I was told that a doctor, who was a friend of the president of TI had his house burn down, due to this problem. That is when the modifications started. I am not sure how many houses TI had to buy because of this design.

I know what flashed across the LCD, “I’M MELTING, I’M MELTING. I am somewhat confused about this, almost all of my projects has a smoke discharge, You mean their not supposed to smoke?

@LucasHartmann

5 жыл бұрын

I assume it was more like Ahhh

@benhetland576

5 жыл бұрын

Or maybe "DAVE? DAVE, what are you doing, Dave?"

@RemyRAD

5 жыл бұрын

Any transformer under 18 years of age should not smoke.

The polyurethane insulation on the wires is definitely sufficient for 240V in normal circumstances. The insulation on the 240V model's primary is probably identical. The problem is that you saturated the core with too many volt-seconds. As you know, once the core is saturated, the winding impedance drops like a stone and the current shoots through the roof. Then the wires overheat, the insulation burns off and the primary short out and then current shoots through the stratosphere. I can't believe there's not a primary fuse.

I once saw a SMPS with voltage select switch running on 240V with the switch set to 120V... The back-to-back caps on the doubler were rated to 250V on either side, and were presumably running at 340-ish volts each. The output was stable and no smoke was released, despite the mistake not being corrected for over an hour.

I'll never forget, 1983. When I purchased Curtis Mayfield's, 2 inch wide tape, 16 track, MCI-JH-10-16, analog, Multichannel, tape recorder. Originally costing $20,000. I acquired it used for $3500. And one day. With the machine on but the tape not running. Thick smoke starts to belch out of the take-up reel motor. I jump up and immediately switch the machine off. Then break into a panic. Realizing that, the take up motor has been trashed. And a few minutes later. I switch the machine on. To fully smoke the motor. But it doesn't do anything? You know it's dead. So no bother hitting the play button. Oh wait. It's working. It's working? It's working! And continued to work flawlessly for the next seven years. Tape tensions still on the money. Go figure? I sold it in working condition in 1990. And it never so much even blew a fuse. The fuse didn't blow. But my mind, sure did. But of course. I was also plugged in to the proper power. Because ya might make that lazy mistake with a $100 soldering iron? You don't make that same mistake with a $20,000 value, $3500 investment. No one would be that kind of lazy. And/or then write about it on the Internet. Because the only thing to be learned by that? Is that you can't fix stupid. Mx. Remy Ann David thetruckstudio.com

I wonder if the folks at Weller got a good chuckle out of this. I'll bet they did. Good on ye for sharing the story and aftermath.

It's core saturation. There is an interesting experiment to do. Connect a transformer primary to a variac, with a current meter in the circuit. Slowly raise the voltage and go above the transformer's designed input voltage. You will see a sudden rise in current at a certain voltage level as the core starts to saturate. In the USA, we use 120 and 240. Usually the 120V is protected by a 20A breaker; but 240 is used where a lot of kilowatts is needed. It's not uncommon for a 240V circuit to have a 30, 40, or even 50A breaker. So when things do go wrong with 240 in USA the results can be quite dramatic.... and smelly! A visitor to went so far as to twist the pins on the cord of my vacuum cleaner so it would fit the 240V air compressor outlet, because it was closer to his car and he wouldn't need an extension cord. You would not believe how much Magic Smoke they managed to pack into that vacuum cleaner when they built it!!!

After living for years in a 240V country with a bunch of expats from 110V countries, I have seen *many* transformers. It doesn't seem to matter the type of equipment, if you plugged 120 V equipment into 240V you got the magic smoke. Thank goodness for the more recent variable voltage supplies!

I've always found that wires contain more magic smoke than anything else. As mentioned by others the earlier Weller units had a fused IEC input, it's crazy not to have anything in the primary circuit!

I know that smell exactly, since a college connected a 24VDC controlled industrial relay to 230V. The smell from that insulation is very different from that magic smoke smell, because it is called safety smoke ;) Btw, I find it very disturbing to have a C14 plug on a 120V only device...

@ElmerFuddGun

5 жыл бұрын

The IEC connectors are very common on 120V only and 120V/240V manually switched power supplies. Usually not a problem in North America and other 120V countries unless you are doing something unusual like using a 240V/208V UPS that I've seen a person assume would be OK with a computer without noticing the voltage switch on the back of the PS. Just like any power input you shouldn't make assumptions. It happens with "DC barrel connectors" as well. The worst thing is when manufactures don't properly label their products input and output requirements and _assume_ you will never have it near another product with the same connectors!

@victornpb

5 жыл бұрын

In Brazil they have both 120v and 240v both at 60hz so they have the American and eu plugs and use them interchangeable. So 240v outlets are usually labeled as well as appliances

@rodgerkitchens7183

5 жыл бұрын

@highks Back in the 1970's, I was on an old Nike-Hercules site in Germany. The High Power Acquisition Radar (HIPAR) used 120V 60HZ power. The rest of our equipment used 120V 400HZ power. We had converters to supply both of these, as well as generators for tactical power. We wound up with outlets for both 60HZ and 400HZ that used the normal US connectors. We also had the 220V 50HZ outlets, but they used the German connectors. You really had to watch what plug you used.

@CaspaB

5 жыл бұрын

I use nail polish on power resistors to make "safety smoke" if they overheat.

@dickcheney6

5 жыл бұрын

More like a C4 plug!

Several current soldering systems have switch mode power supplies. Service people used to avoiid them because of the noise they generated but these days everything has such a supply so there is no longer a desire to avoid them. The problem with everyone using IEC cords is you can easily plug something into the wrong voltage. That was an advantage fixed cords had over these.

@Basement-Science

5 жыл бұрын

Honestly you would think that every device sold today would have an SMPS, but apparently it´s not worth investing any development into these products and pay the higher materials const of a mains transformer instead.

no fuse on the primary? come on Weller, even my DIY stuff got one.

@glennchartrand5411

5 жыл бұрын

American electrical code requires a 15 amp breaker on the outlet and GFI protection on any outlet near water. We also require double insulation on all tools. We place the safety devices inside the distribution box instead of in each appliance. Thats something you need to keep in mind when bringing American appliances into other countries.

@staevobr

5 жыл бұрын

@@glennchartrand5411 - It is the equipment designer's responsibility to ensure their equipment doesn't not become unsafe. It is not adequate to assume that household protective devices exist or will function to minimize any potential hazards. No excuse not to fuse the primary in this equipment.

@glennchartrand5411

5 жыл бұрын

@@staevobr that transformer was designed for the N.American grid. It would have operated safely for a century. Here's a litte factoid about American voltage ratings. 115 V means it can run on 50 or 60 Hertz power. 120 V means 60 Hertz only We created the 115V rating just to let people know if something is compatible with European frequency. ( We also put a yellow stripe on the green grounding wire if the appliance can be converted to 220V 50 Hertz.) 230 Volts at 50 cycle would short out that transformer faster than a fuse could blow. It arced through the insulation the moment he flipped the switch. We put mustard seed oil in the varnish on transformers so that people can easily see and smell an overheating transformer. (thick dark grey smoke with a very strong distinctive smell BEFORE there's an actual fire. ) Thats why smoke poured out of the thing within seconds of being plugged in to the wrong voltage and frequency. The smoke and strong odor he is complaining about is a design feature to grab peoples attention before the transformer actually catches on fire. We've been adding mustard seed oil to coil insulation for over 100 years. You shouldn't plug in anything rated at 120 Volt on a 50 Hertz supply.

@0x8badf00d

5 жыл бұрын

@@glennchartrand5411 Arcs at just 240 Vrms? That would mean not considering PEBKACs, not overspeccing the enamel and getting wire with so thin enamel it could only be used for 120 V.

@glennchartrand5411

5 жыл бұрын

@@0x8badf00d the main issue was the frequency (50 Hertz) On transformers the inductive reactance lessens as frequency drops. This transformer would have failed at 120v 50Hertz . Overvoltage (core saturation) only accelerated the process. You've misdiagnosed the main cause of the failure.

I'm shocked! No fuse on the primary side!!! And we are talking about a Weller brand. That's a shame.

@gaborballa8566

5 жыл бұрын

​ Dana Vixen If you watch it carefully you will see that's on the secondary side. It should have protection on both side!! I think a glass fuse is a basic thing to have in circuits like this.

@bonzaihb3432

5 жыл бұрын

@@gaborballa8566 exactly! For that amount of money, even for an entry level device from a supposedly high end manufacturer, this should be mandatory, full stop.

@DarronBlack

5 жыл бұрын

I've had issues with two WESD51s, including a replacement iron. (Temperature going to 900-ish on the screen and going cold) Shaking the irons usually fixed it, until it progressively got too bad to bother with. I gave up, went with a pair of JBCs. My WES50 lasted well over a decade. I don't think Weller means what it used to as a brand.

@DarronBlack

5 жыл бұрын

One of the WESD51s started having a problem a week after I bought it... and the replacement iron for the other one worked for 3-5 weeks (don't recall exactly) before it started having issues (but it lasted maybe 4 months before I gave up on it)

@pault5179

5 жыл бұрын

Even better HRC sand-filled ceramic, glass can explode with high fault currents ... electronics.stackexchange.com/questions/31366/fuses-what-are-the-practical-differences-between-ceramic-and-glass-cartridge-fu

8:58 you call it utter trash, but it does have a fuse, unlike the genuine one lol

My first son at the age of two had a fascination with electronics and discovered the AC 120/240 switch on the back of computers and reversed the setting. It took a long time to figure out what happened. I'm an American so no magic smoke for me. (Thank God!!) Its funny, now he's a computer hardware engineering student. I should tease him about that now, that and the fact that he effectively demonstrated that you CAN get three CDs in one drive at the same time, but don't expect them to work or be easy to remove. :-) ...oh those were the days. :-)

Years ago I snagged a complete WTCPT out of the bin. It looked perfect but it had no power light. Opened it up and found an internal blown fuse ! I installed an externally accessible fuse holder and "Bob's your uncle" !

It's been my experience there is a thermal fuse buried in the wingdings. Covers both over current and over temp failures. Usually one of the lead outs is silver because it's the lead of the fuse.

So Weller is shite? Cost-cutting to the point to not include a fuse on the primary side of the mains transformer?

@davidwoodbridge862

5 жыл бұрын

Weller has always been shite, just most people have never seen or used a real soldering iron!

@0dium.

5 жыл бұрын

cut the crap man :) I have an old WECP-20, it was the state of the art 20 years ago, and still decent today !

Put the transformer from that crappy Hakko knockoff in the Weller if it is close to 24 V.

@Basement-Science

5 жыл бұрын

lol that would probably work. And while you´re at it, put its fuse in the weller as well!

@MrOrangeman18

5 жыл бұрын

Jacksat but then it will defo catch on fire:(

@scottfirman

5 жыл бұрын

Thats what I was thinking!

@rasz

5 жыл бұрын

MrOrangeman18 no, hakko clone has actual fuse

@WaltonPete

5 жыл бұрын

@@rasz Yes, but I doubt the transformer insulation is anywhere near as good as the Weller transformer.

If there is anything more fascinating than seeing the internal workings of things, it is observing the aftermath of catastrophic failures.

@EEVblog Dave when I was 17 in my first EE job I plugged in a brand new 110V Williams pinball table into 240V... Prolly a £2,500 piece of kit in 1982... KABOOM!!! :D

Very substandard construction. No fusing.... No boots or heatshrink on the connectors.. no thermal cutout on the transformer... Not the kind of thing I'd expect from Weller

@GoldSrc_

5 жыл бұрын

Blame Weller, it doesn't matter where it was made if this was how Weller wanted it to be :P. Give a skilled worker shit tools/components and the job will end up like crap.

@TestECull

5 жыл бұрын

Nothing substandard about it. It was made for the US market and that is perfectly fine in the US market. You don't need boots/heatsrink on connectors that nobody's ever gonna brush a finger or drop a paperclip across, and we don't require fusing or thermal protection on mains devices over here.

@TheChipmunk2008

5 жыл бұрын

@@TestECull Depends if you're going for the bare minimum or want to protect your brand credibility. And no fusing on a device that could be connected to a 20 amp circuit... but which draws less than 1/2 an amp... is a dick move, no matter which rulebook you're working to. It's pure 'fuck you, mere consumer'

@TheChipmunk2008

5 жыл бұрын

The lack of boots might even meet proper class II.... but. No fuses, in a place where the plugs don't have fuses? HELL NO

@TheChipmunk2008

5 жыл бұрын

Hint, i'm not gonna look favourably on weller after this snafu. and someone with actual purchasing power MIGHT feel the same way. Is Weller willing to take that chance?

Not as big a piece of trash as the Weller WR3M. The vacuum pumps are complete GARBAGE and they refuse to sell the pump as a spare part. They have every other part available though. I have 8 of these and have to pay $400 for the Weller “repair” swap-a-roo center to replace the bad pumps every 1-2 years each unit. I suspect we are getting used pumps pulled from other units, never even getting the machine we sent in back. I sent in a cosmetically perfect machine and what I got back was a piece of tired and worn shit. Whoever used that one liked to use the hot iron tip to turn the power off and on repeatedly!!! The WR3M is $2,500 for 1, so make that 8....that is an investment you respect and take care of. In addition to all scratched and trashed machines from god knows where.....I even get different model versions as a substitute (earlier versions). My glorious armada of pristine soldering stations is now a hodge podge of ghetto trash. Sadly, I have to say avoid Weller as they are going into the toilet like Apple. All they had to do was offer the pump impeller assembly like they do all their other parts and I would be happy. Otherwise, the fact is they are intentionally designed to fail and roll you over the Apple barrel. Go Metcal.

@AlexLaw_Qld

5 жыл бұрын

Nail polish dots tell you what comes back and what is "new". Be paranoid, it can be entertaining.

@jamieeast4974

3 жыл бұрын

"Milking it comes to mind"

Useful video 👍 Good quality

Thanks for this video I’m about to buy the Weller soldering iron so nice to see inside 🇬🇧🇬🇧

You know, you are always complaining about soldering stations not having the features you want. You are an engineer. Make the perfect soldering station. That would be a a fun series of videos to watch. Electrical design, physical design, CAD modeling, microcontroller programming, etc.

@dashcamandy2242

5 жыл бұрын

The EEVBlog Soldering Station would make a good companion to the EEVBlog Multimeter.

@L0j1k

5 жыл бұрын

I see what you did there. I support this 100%. +1 would insta-buy.

@argonathcirith

5 жыл бұрын

Totally agree with this idea

@FennecTECH

5 жыл бұрын

Try and make it sub 100 too!

@HipocratesAG

5 жыл бұрын

and more important, must be anti-muppets! What kind of moron connect a 120v to a 240v outlet?

I just find odd to have a IEC plug on a 110V only device! The lack of a fuse in the primary side is really a bad design, fuses and holders are not so expensive!

@ethanlamoureux5306

4 жыл бұрын

Here in the US, IEC plugs are ubiquitous, so I wouldn’t look twice at it. However, now that you mention it, I think maybe most devices with an IEC plug also have a dual voltage power supply, while 120V-only devices have the cord hard wired to the device.

I forget whose law states "The equipment will blow to protect the fuse." That is normally the case in situations like this.

It's not the lack of a fuse that is shocking (no pun intended) a fuse probably wouldn't help anyway. It is the fact that it has an IEC C13 connector, inviting idiots to plug a 230V kettle lead into it. It should have a fixed wire with a 120V plug on it, then at least they have to cut the plug off and wire their own on before they can burn their house down. At least that might make them think for a moment!

Wow, srsly? According to Reichelt, this thing (well, the 240V version) is 144€ (edit: reduced, original price around 170€), and it does not have a fuse? Even my el cheapo Xytronic station from Taiwan for 75€, and also the even cheaper 25€ no-name hot air station from China has one. Not impressed at all... Edit: and it even does not have a socket for a ground strap? WTF Weller... but surely, the CEO earns enough to afford a Porsche, I guess? m(

"Designed & engineered in Germany" As a German, I am ashamed now. Especially because we have 240 Volts in Germany, too. EDIT: 230 Volts ;)

@marsa74

5 жыл бұрын

Lonzo Da Man Don‘t feel too ashamed. Weller was founded in Philly, is part of the Apex group, but, yes, they have a branch in Germany. Everywhere around the world you‘ll find stuff claiming „German Engineering“ but copied from a news forum in German language where students discussed their work.

@AdaptingCamera

3 жыл бұрын

Actually, you don't have 240V in Germany, only 230V...

@lonzodaman

3 жыл бұрын

@@AdaptingCamera My multimeter agrees with you. But IIRC it was set per regulation in the 80s to a range from 220 to 240 Volts (but I could be wrong on this)

@AdaptingCamera

3 жыл бұрын

@@lonzodaman Never the less, the AC mains voltage in EU is 230V (+/- 10%) 50Hz. There are some variations, but I have NEVER heard of that large difference, normally only 1-2% up or down. Everything else is very rare. Saying that "we have 240 Volts in Germany" is simply wrong, even if you occasionally can measure 240V, that's not the same as the whole Germany is measuring 240V at the same time.

Many years ago, I was a tech rep for a printing manufacturer. I needed to repair a board from a printing press at a customer's place and used a standard Weller soldering gun. When I pulled the trigger, a cloud of smoke INSTANTLY (probably not more than 1 second) belched from it. I measured the receptacle voltage and it was 208V. The electrician had apparently wired the circuit to the high leg of a 3-phase system. I am still using that gun 30 years later! I duct taped the outlet and informed the owner of the problem.

I dont know much about the general state of soldering irons available to you but I use a number of cheap tenma units for simple led work and they can all take 120-240v. I also have a slightly higher end atten unit that again can take a range of voltages and doesnt care if youre on 50 or 60hz. I doubt either of these irons are as expensive as the weller so that thing in my view has no excuse for going pop

Photonicinduction style....

The reason it happened may be of interest: it wasn’t an insulation failure or breakdown that precipitated the smoke escape. The high voltage in itself is not a problem at all: the winding and the insulation would have handled it. The problem is that the core was minimally sized and saturated as soon as the voltage got over 130V or so - also since Aussie 50Hz eats away at whatever margins were there in a 60Hz transformer design. I have a similar 120V Weller model and the saturation indeed starts around 125-130V 50Hz. By the time you reach 240V AC on the primary, the winding behaves like a ~50Ohm resistor fed from a 50% duty cycle 120VRMS supply, and promptly overheats, producing the mesmerizing billowing smoke :)

Here's one of the few things I enjoy about being in the US, we rarely have to worry about feeding the wrong mains voltage into something, especially feeding too much voltage

Who assembled the transformer with brown sugar? :-)

Obviously not as well built as that grilled cheese toaster. :)

@Mike_Downey

5 жыл бұрын

I was wondering if someone was going to mention Barry's toaster

I once accidentally connected a wire to the wrong terminal in the breaker panel and fed a circuit in my house with 240V instead of 120. After I switched the power back on, I casually made my way from the basement where the breaker panel is to the second floor office, and as I entered the office I saw a lot of smoke coming from the wall wart transformer on the cordless phone base, which was still powered up and appeared to be working normally. At that exact moment I heard a loud POP! and the lights and display went out on the telephone base/answering machine, and I immediately knew what had happened. So I ran to the basement and shut the breaker off, then reconnected the wire for 120V. The plug-in transformer was toast, of course, but when I found a replacement transformer, the telephone base was in perfect working condition. I figure it was designed for a wide range of input voltages, and in fact many DC voltage regulators can handle a doubling of input voltage without overheating or damage, and maintain proper output voltage too.

that's a common issue here in Brazil, a lot of people have both "110" and "220" in their homes but forget to check which wall plug is each one

Are you going to add a switch mode psu to replace the transformer and rescue the station!

@UnrealTransformer

5 жыл бұрын

Don't work because we need AC not DC.

@galfisk

5 жыл бұрын

You don't need to rectify the output of the SMPS if you don't want to (except maybe for feedback purposes). Whether the circuit can work with tens to hundreds of kHz AC is another question, but I wouldn't rule it out completely.

@johnfrancisdoe1563

5 жыл бұрын

galfisk Running 100kHz down that iron cable doesn't seem good from an EMI standpoint. A normal SMPS keeps the higher frequency stuff paths to a few cm at most. But then again it's still longwave with medium wave overtones, so a 2m lead might not be a problem.

@uzaiyaro

5 жыл бұрын

It’s only a 24v output. These things are everywhere.

@w9gb

5 жыл бұрын

SMPS, NOT NEEDED. Dave just needs to source a COMMON 240 Volt to 23/24 Volt HVAC (heating, cooling) transformer at 2-4 amps that is same size. THESE exist .... since those same HVAC transformer suppliers were OEM suppliers for some earlier Weller products.

Delete the transformer,install some banana jacks to power it from the shop psu and carry on :)

Back in the early '90s when PC power supplies had the 110/240V switch at the back and the power switch in the PC case actually switched mains (286 and early 386 era), a colleague of mine had just finished assembling a new PC, and pushed the power switch to test. There was a blinding flash like a professional camera flash accompanied by a bang that would have made a .22 pistol proud. Then complete silence in the entire shop (the assembly area was at the back of the display section where customers walked around). I've never seen someone jump back so fast. Turned out the power supply was set to 110V.

You're exactly right about core saturation. First off, transformers are designed to run at about 70% of core saturation. Running it at 50 Hz reduces the voltage handling of the transformer by 20%, because voltage to frequency ratio is proportionate. You effectively put more than double the voltage it's designed to handle, because doubling the voltage, along with the lower frequency. The primary basically took 145 volts, at about 8 Ohms. It's no wonder it went up in smoke straight away. That core saturation likely kept the secondary voltage down, protecting the control board. There IS something missing! Typically, when they fuse the secondary of dual bobbin isolation transformer, there is a thermal fuse tucked into the gap of the primary winding. This fuse does NOT sense, or protect against current. They're typically rated at 10 or 15 amps. If the transformer winding gets hot enough to heat the fuse up to the boiling temperature of water, the filament melts, breaking the circuit. In the United States of America, it's required by law, to have a thermal disconnect on the primary side of the transformer.(possible quality control issue here) On your other cheap soldering iron controller, the primary measured 64 Ohms. If that transformer was rated for 120 volts, it would have measured 8 Ohms, 1/4 the resistance. That would keep the I^R loss the same, because of doubling the amperage on the primary, to produce the same wattage.

no fuse on primary side, what a terrible design oversight, I wouldnt expect that from weller

@Detroit8V92tta

5 жыл бұрын

Yeah I have to agree. It really should have a fuse on the primary winding. However where does it stop? Clock radios? Etc. Hmmm

@Pops180

5 жыл бұрын

No regulations call for a input fuse on devices like these so long as the cord is short enough. It's always best to understand the equipment you have .

@0x8badf00d

5 жыл бұрын

And they got three on the secondary side. Why not put one fuse on primary, one fuse for the iron and the polyfuse for the control board?

@Detroit8V92tta

5 жыл бұрын

@@0x8badf00d..because overvlotage on the primary is a rare occurrence. It was an oversight by Dave. It would be expected that if you are going to plug in a soldering iron you kinda know what you are doing. Sure you can put it a polyfuse for that, and a HRC for this, but where really does it stop. Read the placard is the moral of the story.

@Detroit8V92tta

5 жыл бұрын

@@0x8badf00d Fuse on the plug. My original comment.

I thought transformer laminations were interleaved alternately, rather than all the E stacked on one side and all the I on the other

@animatrix1851

5 жыл бұрын

You could do that but you would need the coil to start the interleaving process. If you were to get pre laminated E and I blocks all you'd have to do is weld them together saving you some time.

@paulstubbs7678

5 жыл бұрын

In the early days they were, one could disassemble and rewind with relative ease, unfortunately the bean counters usually insist in a cheaper, non-repairable approach.

Interesting to see it's actually a proper circuit board in there. The last Weller soldering station I saw inside, had a thin ceramic substrate with printed resistors etc. on there. But the station had been dropped and it cracked the ceramic board, and so that was the end of that.

Nice too see the expert willing to say and show his own BIG MISTAKE! Good for you.

My first Weller, that I bought 25 years ago still works fine with it's good old iron core transformer, I'm not sure that an smps would have made it so long without annoying me with dried out capacitors or shorted semiconductor. By the way back then it was quite expensive, especially for my young boy budget^^ , but I can still find spare parts (and not only solder tips !) Can you believe it ?

@JanicekTrnecka

5 жыл бұрын

Only one explanation..Weller.

@DarronBlack

5 жыл бұрын

@@JanicekTrnecka It was nice that my local electronics shop had a replacement Weller iron for the WESD51... but when the other WESD51 failed 4 months later they hadn't bothered to restock another iron... so I ordered a JBC (I think because Dave did a video on them?). I bought a second JBC on Cyber Monday (not much of a sale, 10%, but whatever) So far it's pretty nice... but we really haven't had them long enough to know yet. Heats up super fast, hibernates quickly in the stand, and hot-swapping tips is pretty nice. Parts certainly aren't going to be as available, but we got a fair number of tips. The PIN-code settings lock is weird, though.

Is there a 240V version of that station that you could by a replacement transformer from that model to repair it. Wonder if the original cord had a fuse in it, some American devices are sold with a removable cord that has a fuse in it (stupid practice , I know, right?) , like sitting next to me right now is a Holmes brand box fan that doesn't have an internal fuse but rather relies on the included removable cord has a one of those slightly modified C7 connectors on it with one square side I'm sure I could find a non fused cord lying around from an old radio or something that would plug into it.

@Basement-Science

5 жыл бұрын

That´s the stupidest thing I think I´ve ever heard of lol. Fuses in a removable power cord? come on, who came up with that?? Anyway, he could buy any 240v/24v with a similar power rating and put it in there. No need for anything special.

@elvinhaak

5 жыл бұрын

I guessed that. Is it still 'normal use' to keep the fuse in the cords? I remember these special cords on computer-equipment (and because we didn't use the cords, we took the fuses out before tossing the cords away when we re-equiped it for 220-230 Volts).

@VintageTechFan

5 жыл бұрын

@@Basement-Science Especially if you use a totally common power input connector. If that would have been a proprietary plug, it would still be a stupid idea, but a standard connector? That's just crazy.

@jort93z

5 жыл бұрын

Thats not that stupid. If you have a fuse in the powercord, you can more easily replace it. Easier than if it was on the pcb anyway.

@VintageTechFan

5 жыл бұрын

@@jort93z You aren't supposed to replace a fuse on a regular basis. You should think about why it blew. Also .. just put it in a fuse holder on the device like it was done for decades.

I have the same soldering iron and almost did the same thing! Good thing I looked at voltage specs before flipping the switch!

Dave, the main problem, as I see it, is the core design. 60 Hz transformers don't have as much iron as our (NZ & Aussie) 50 Hz ones and also the stacking of the laminations. All the "Es" were in one direction instead of being alternately inserted. The fact that the transformer was welded rather than being screwed or glued is another pointer to its destruction. That weld is like the shading rings on a shaded pole motor... they get hot. Lots of eddy currents. The dark colour of the winding wire (secondary and what little of the primary) visible, suggests a high temperature insulation but with four or more times the power flowing due to over voltage and under frequency and no fuse, that won't have lasted very long. . My experience comes from working with inductive ballasts back in the 80s and 90s, testing imported fluorescent light fittings. Even 220 volt ballasts run on 230 volts caused similar melt downs after a day or so. They welded the laminations to stop that annoying humming (because they forgot the words) that old fluro fittings made. The trouble with fluros is worsened by the tube becoming lower in resistance as the ballast heated the whole fitting and the fact that they are often mounted in hot places to start with. Something to try out in a future video?

Take it you don't have a fuse in the plug top as we do in the UK.. Keep the good work

@daveturner5305

5 жыл бұрын

In the UK the plug's fuse, if correctly sized, is only to protect the house wiring and the cable from the outlet to the equipment. NOT the equipment itself! Using an incorrectly sized fuse , typically using a 13A fuse where a 3A would be more suitable (which now is most of the time) can cause fires as the equipment cable overheats.

@willyarma_uk

5 жыл бұрын

That is correct

@johnnodge4327

5 жыл бұрын

But having a fused plug is still better than not having a fused plug, even if the plug has a 13 Amp fuse fitted. Having said that, 3.1KW of available power in the UK will make a big mess to those tiny primary windings.

@Basement-Science

5 жыл бұрын

The fuses in UK plugs just allow you to use a thinner cable from the plug to the equipment, that´s about all. The house wiring has to be correctly protected by the circuit breakers in the distribution board.

@daveturner5305

5 жыл бұрын

Absolutely - no contest. We are in agreement.

Weller, please send dave a new iron.

@IIGrayfoxII

5 жыл бұрын

I think he has enough "soldering stations"

@thomasbonse

5 жыл бұрын

@WhiteShadow2k1 Unless you've not left yourself any room on your bench to actually do any work. Then the solution is obviously to get a bigger bench and/or lab.

@gorillaau

5 жыл бұрын

@@thomasbonse why do you think Dave has upsized the lab. More solering stations and power supplies to be acquired!

You are the only person I know that has captured the Magic Smoke on video Bravo

The power tranny was a 600V triac. It should withstand the voltage even without the transformer. And you are right, once I want to use a GDR (East-German) 110/220V to 12V transformer (two primeries, you can connenct them serial or parallel) for my tcp-24 solder iron, so I gave a try and plug it into 230V as a 110V device and it didn't burn, but it was very loud.

take chinese clone apart for transformer (and it's fused connector for a good measure) and fix your mistake xD

@xenonram

5 жыл бұрын

Or just buy a transformer. That's like saying, "The transmission in my car just took a shit. Looks like I'll have to buy a new car to take the transmission out of."

@ok_engineer

5 жыл бұрын

@@xenonram It's not like he's going to use the knock-off Hakko station so if it's a match, might as well use that because the driver board is a much better than the "Fakko." And regarding your comment, I know countless people who have bought cheap cars from a junk yard and taken the transmission from that.

primary side will be fused with a hidden thermal fus3 inside the windings ...

@mikeselectricstuff

5 жыл бұрын

This is less common on bigger transformers.

@pierreburton4523

5 жыл бұрын

Yeah.... that's going to help when the windings are already shorted.

Dave, you should use a visual indicator on all your 120Vac-only equipment so you avoid this issue in the future. A similar thing happened at my place of employ with the brother of my supervisor connecting a 220Vac device into a 440vac outlet. (They use the same connector.) Now all the outlets are marked with the supplied voltage.

Of course in the earlier types which had the holder for the soldering iron on top of the box, it was an advantage to have the classical transformer in it (and not a switchmode supply) because it doubled-up as a dead weight to keep the whole thing in place when you carelessly put the iron into the holder.

Doesn't a 120V (US) device have a different mains plug than an Australian 240V one?

@98081

5 жыл бұрын

This has an IEC C13/C14 connector which are used in both 120 and 240v areas. Really a mistake in the standards if you ask me.

@jort93z

5 жыл бұрын

The wall plug is different, but the connector on the actual device is the same. its a standard IEC connector. You can plug any lead with any wall plug into it.

@WarpRadio

5 жыл бұрын

its not the plug end.. in his country the IEC end has a 220 plug.. which this situation should NOT have happened as IEC generally means "120/240 compliant".. but, then, China broke the rules!

@jort93z

5 жыл бұрын

What do you mean china broke the rules? that weller was designed in germany and made in mexico.... Also, does IEC mean 120/240 compliant? i don't think that is required.

@WarpRadio

5 жыл бұрын

@@jort93z perhaps: but I'm guessing the transformer was from China.. I donno- I was just trying to say that the way things are made today, "its the bottom line that's the most important"; I have had many a 'tranny' fail in some top-notch equipment such as Furman, Sibex, DBX and Mackie.. and they were stamped "made in China"! As far as "120/240 compliant" is concerned, I'm not entirely sure on that, exactly.. I CAN say that MOST of the stuff I have seen with that connector on it CAN accept 120v and 240v (usually by means of a switch) such as computers, and some/most universal pro audio equipment.. but in the states, that connector can also be used on 120v only stuff too.. the problem comes if/when that equipment is taken overseas.. but the stuff that's already overseas, that uses an IEC connector, seems to all be 120/240 compliant. thanks for your comment!

How does it take you more than 4 weeks to unpack your lab stuff. Every video you have an excuse why you cant access your gear

I don’t undetermined why keep laughing with smoke over and over again. Giggled when you said, then I remembered it was 110 volt. Fun video

Brunt solenoids on pinball machine (common failure) looks that way and smell the same, as do AC motor (had a centrifugal starter failure on one, thus over-current, and rotor looked the same). Enamel seems to "boil" and expend from the winding as it heats up. The motor was rewound and works like a charm.

There should be no way to plug 120/240 Volt plugs into each other.

@N3szt0r

5 жыл бұрын

Try to avoid that :) likes benzin vs diesel...

@christophermurphy408

5 жыл бұрын

The problem is IEC connectors are fantastic for computer equipment etc that is dual voltage however in this case I think Weller should have had a fixed US plug which definitely would make you think twice before putting it on a plug converter.

@deceitive3338

5 жыл бұрын

Technically there isn't, a US/Canadian plug won't fit into an Australian (or European) socket, Dave must have been using an adapter here. If it had an Australian plug Weller would be liable for any damages...

@DanafoxyVixen

5 жыл бұрын

@@deceitive3338 "Technically there isn't, a US/Canadian plug won't fit into an Australian (or European) socket, Dave must have been using an adapter here." Nope, no adapter needed as it used a IEC connector to connect to the power lead

@deceitive3338

5 жыл бұрын

@@DanafoxyVixen Ah you're right, just rewatched. That's awful, devices with an IEC connector should be required to have a 240/120v switch (and appropriate transformer). At bare minimum should be fused. Crazy

Thumbs down for the fake thumbnail image.

@subWOOFFA

5 жыл бұрын

I stayed for the whole video thinking Dave wouldnt do that to us

@ElmerFuddGun

5 жыл бұрын

The thumbnail looked obviously "fake" to me before I clicked on it. Dave's done fake flames before too but they were also obvious. Search back it was a PS from China that Dave was building into a case. Maybe a year ago?

@uzaiyaro

5 жыл бұрын

ElmerFuddGun Yeah, same thing with the power supply. But the things weren’t on fire when he was filming. Also, I just got one of those power supplies and it’s awesome! A kilowatt of power for $60! Thankfully, what caused that failure - a bypass/filter capacitor on the output that was susceptible to physical damage, has been completely removed.

Did I like it? Always, mate! You didn't burn the new lab down so you're still winner winner! You're human so mistakes can always happen. You just give us a bit of fun with it. As long as you keep making vids, I'll keep watching them! Thumbs up, always! Peace, mate!

At 5:13 there is two levels of transformer primary protection. The small round lead device is referred to in the US as a Bell Fuse and it is in series with what looks like a tan capacitor. That is a self resetting polyfuse. At excess voltage it is likely this let out the magic smoke. The primary connects to the left most terminal which does not go to a winding. It then goes through the two fuses in series to the 2nd terminal, which is a lead from the primary. In viewing the transformer, it is most likely just fine. Check the bell fuse, and replace the polyfuse. The polyfuse most likely let out the smoke which quit when the bell fuse popped. Most of those transformers have a thermal fuse inside the windings as a last resort to prevent fire. This is not replaceable. Change the fuses.

yeah cover up the smoke head fast when the smoke comes out ! But where I worked the smoke in a room didn't set off the building system ( only sent a warning at first ) until 3 or 5 minutes later - giving people time to get the burned popcorn smoke cleared out . The smoke detectors in the hallways do set the building into full alarm right away though.

I used to work in the UK for a US company the number of PSUs we blew because we forgot to change the voltage link was staggering. After a while you would automatically check but sometimes if you were in rush magic smoke.

In the 80's I worked for a transformer company here in Melbourne, I was an Armature coil winder, the transformer used in that soldering iron is what we called "junk wound" the ones we made used multiple turns of enamel coated copper wire, but we also used to place a sheet of insulating paper between each layer, this limited the chance of a short, in this case, it looks like the enamel broke down because the voltage was too high.

Good job Dave! You have successfully released the shmoo.

This is sure an interesting self induced problem. Did this myself to an HP3478A, though it did state that it were set to 240 volt according to the labeling on the back, didn't cross my mind that it wasn't set to the correct tap within... (were set to 120, and now the transformer is dead, but gave me a power supply project to work on, even if I would have preferred a working multimeter.) And talking about linear transformers compared to switch mode ones, I recently took a look at a T12 knock off solder station, that uses a switch mode power supply internally, also has a nice and compact form factor. And for its price it is practically flawless.

No worries mate. Oh well we have probably all done this at some point. It’s funny countries go to some effort to have there own plug and sockets and how easily it’s defeated buy the IEC connectors. From the amount of smoke you mentioned it’s typical of a transformer going up.

Insulation wasn't hurt by over voltage, but over temperature, that is what melted the insulation. But yes primary should have been protected.

The low primary resistance only figures into power dissipation under the assumption that the primary current bypasses most of the windings - probably a correct assumption in the case of a smoked transformer :) Just to clarify, then: such low impedance doesn’t matter when the current makes it through the windings, because it’s not the (low) wire resistance that determines behavior then, but the inductive reactance. The primaries have “high” resistance only due to other constraints, it’s not somehow a requirement that transformers have high primary resistance. In fact, it’s a drawback, because that resistance contributes to heat dissipation. An ideal transformer of course has zero winding resistance :)

I had an HP rack mounted UPS burn up like this about 15 years ago. The electrician in the data center had mis-wired an outlet. HP replaced the unit, but there was no fuse on the mains. That thing poured smoke!

Yep, only thing in the US we use 240v for are large appliances, like the AC, range, clothes drier, etc. 240v 50 amp supply for the range, now that's a lot of power.

I realize this is very late to comment, but I just saw this video, and I can add a few things about the regulations about fusing in North America (which is the market this device was designed for). Here, at least, the wiring in the wall is protected with over-current protection in the fuse-box or breaker panel, and the device being plugged in... well, it needs to take care of itself, because the supply isn't going to help it. The general gist for small transformers (control transformers and the like) is that they can be fused EITHER on the input or output side. Of course, you can fuse both sides if you choose. I usually do that in the panels that I build, but it's not actually a requirement. Now, I just bought one of these Weller soldering irons (the WE 1010 NA) a few days ago. It's at work, but I'm going to check it out and see if they added primary-side fusing to it. I didn't happen to notice when I looked at it after purchase. I've used it for about an hour so far and I like it a lot.

UL standards are commonly used in the US for safety guidelines. UL (Underwriters Laboratories) is NOT a government agency, but was originally organized by the insurance companies, collectively. When stuff was made in the US, and respectable exporting countries, like Japan, they usually followed UL standards. For electrical items, the goal is to make the product, so it neither presents a fire or shock hazard. UL Class 2 transformers, often used in HVAC (heating & air conditioning), when overloaded usually fail, by opening up the primary winding, long before the enamel insulation starts to vaporize. That thin gauge wire on the primary should have melted, in only a second, or less. The core should have saturated, passing much more than the 4X power, because it would no longer have any significant inductance. I'm surprised it didn't open up almost immediately !