EEVblog

[@EEVblog]

For those asking, I checked the TRIAC. It hasn't failed short, but it doesn't detect as a TRIAC with the Mtester (possible not enough current for that). Quick follow-up video coming shortly.

[@JKnight89]

Ok after seeing this, you make me wanna remake my hot air stations control board...... off brand Atten,i think, 858D...

[@robertw1871]

Could be latchup, might not have zero crossed to shut off, could be a cosmic ray hit it at just the wrong moment....

[@alexreeve]

is there a blocking cap across it?

[@FrozenHaxor]

I've had a diferent chinese model at work fail where the comparator in regulation circuit failed and it constantly drove the heating element.

[@2soldierman2]

This would have been my guess. Triac/mosfet failure.

[@ManWithBeard1990]

Probably taking over the Weller mentality: everything is a fuse if you use it wrong enough.

[@EdWatts]

Every ship can be a minesweeper... ...Once.

[@iainportalupi]

“Everything is a fuse if you use it wrong enough!” Needs to on a teeshirt!

[@drussell_]

This is why every bench needs an "Explosion Containment Pie Dish" for just such an emergency! :)

[@tuttocrafting]

Big Clive

[@nightshadelenar]

Ah, true. Just like Clive has one for "lithium and chemical explosions", would be nice to see dave use a few.

[@johnfrancisdoe1563]

Jeffrey [Equine Sanctuary] Unfortunately this would have been way too hot for the explosion containment pie dish, it was melting the metal while receiving fresh power until unplugged.

[@BrucesWorldofStuff]

Yep Big Clive convinced me too! I have the "Pie Explosion Dish" on my bench just for such occasions... :D

[@nightshadelenar]

@@BrucesWorldofStuff They're very useful for little lithium incidents, like stabbing the lithium cell with your spudger.

[@dalehorton7748]

The reed switch doesn't control the fan, the temperature feedback loop does. It keeps running for a minute or so after the handle is put on the rest. If the fan stopped as soon as the handle was put down, then it was certainly a fan failure.

[@wolvenar]

You are particularly right. The reed switch is feedback to the controller to know to shut down the heater and fan once cooled.

[@JJayzX]

@@wolvenar I believe when he put it down the reed wasn't triggered and fan happened to die. Now what caused the overheating was without the fan blowing the thermistor wouldn't get a proper reading now. It might have actually detected cooler temps from not having air passed through the length of element and raised temp to compensate.

[@Chris_the_Muso]

This was my thinking as well. I don't believe it actuated the reed switch when he put it down, and the fan failed at that exact moment - the fan should have kept on going as long as the heater was over 100C. That should have been his first clue. I've had my fan start up again if there's any residual heat (I have a Yihua 878). Dave is right, it should have still tried to regulated the temperature, however with no airflow happening all bets are off.

[@wolvenar]

@@JJayzX Pretty much spot on I would guess as well. Though at some point the thermistor should have gotten warm enough. Probably to warm to be safe though.

[@xxportalxx.]

Not neccesarily, if the heater is designed to operate safely only at a fraction of the applied voltage, thus relying on a pwm scheme of sorts to keep the average power down, then a triac or controller failure could easily overpower the fan's cooling ability.

[@richardrudek01]

If the thermocouple is the only sensor in the handle, then without airflow, you obviously can't detect the runaway fast enough, as you will be relying upon convection only. So the plastic (in the base) will melt long before convection gets the thermocouple (at the exit) up to the set point of, say 400 degress C. Other strategy(ies) will be required.

[@EEVblog]

It's covered in metal and mica insulation so I don't think radiant heat would be too bad.

[@mckryall]

Richard Rudek I think it'd get VERY hot sitting next to all of those heaters, hot enough to trigger a cutoff if the cutoff circuitry were functional

[@donkeytits1]

Nup. This guys on the money. You ever put your hand over the back of a hair dryer? No heat out the end and glowing element wires in about 3 seconds

[@alfoncejean8826]

it would be interesting to test the actual output of the sensor whith the fan off. not sure how duable in the states this station currently is

[@Promilus1984]

well third wire (speed feedback) on fan would prevent overheating due to insufficient air flow (stuck fan) but wouldn't if blades were broken and motor idly rotating.

[@HighlandSteam]

Not vibration isolation but seal to force all air forward.

[@EEVblog]

Yep, does that too.

[@teardowndan5364]

@@EEVblog Pretty sure that's its primary if not only intended function.

[@EEVblog]

Sure, gotta make sure the air flow out and not backwards.

[@tokin420nchokin]

Lol​@@EEVblog

[@LazerLord10]

Yeah, I have one of these (similar), and the thermal sensor is in the path of the airflow (where you'd want it to be). You only care what the temperature of the air is during operation, not the coil (until it goes meltdown). Likely, a thermal fuse on the coil would be what you want. I could tell because if I set the airflow to near zero, the coil would just turn on all the time and get quite toasty in a hurry.

[@TheDefpom]

I suspect the triac is the original fault, shorted out so the element didn’t power down when it was put back in the cradle, so the controller tried to shut it off and turned off the control signals for the fan and element, but if the triac shorted the element wouldn’t be able to have its power shut off.

[@EEVblog]

That doesn't explain the failed fan though. Bit of a coincidence to get a TRIAC and fan failure at the same time, unless the fan failure caused the TRIAC failure somehow (I don't see the opposite happening)

[@CharlesJCliffe]

There’s several videos online where the TRIAC has failed in these models and caused exactly the same outcome; I think the TRIAC (knockoff part?) failed while using it and didn’t go nuclear until it was put back on the holder.. I’d bet the heater wrecked the fan if anything.

[@TheDefpom]

EEVblog - I know you measured the fan but maybe it’s internal control fooled your test, have you tried powering it?

[@alfoncejean8826]

@@EEVblog overhead from the failed control killed the fan?

[@alfoncejean8826]

@@TheDefpom but is the triac actually failed?

[@wouterkoevermans981]

Dave, pay David so he can buy a decent rework station! ;)

[@randynovick7972]

Aye, Wouter. This. A thousand times, this.

[@BavarianM]

David needs to pay David more 😂

[@Damicske]

A nice Quick 861D :)

[@ToTheGAMES]

@@EscapeMCP Type it right if you want to spam something. RossmanN. Double N.

[@Wilson84KS]

Over the years he made more than enough money with that, no he throw out some thousand bucks for a JBC soldering iron plus some thousand bucks for the station and some hundret bucks for some new tips.

[@DoRC]

Ive got the same gun. I always stare at the temp to make sure its cooling down when it put it in the holder.

[@tmilker]

Why not a more hands on look into the problem instead of just speculation? You didn't even show a multimeter in this video. New lab not setup enough yet to hook up to the heating element, re-solder the fan and power it up and check things and actually determine where the failure was? Or just not worth your time?

[@dorfschmidt4833]

He should check the wires from hand piece to the station for continuity, especially the wires for the thermocouple.

[@jimb032]

Dave is not going to do more than that to check a lowly Yehaaa, Yahoo, or any other brand that costs less than $1000!

[@mckryall]

James Kerns Jr. Consider the effect of such an investigation though, there's more value investigating one of these because far more people have these than have $1000+ stations. As well, the $1000 stations are (usually) good anyway. The cheap ones need more work to figure out which ones are good enough.

[@jimb032]

@@mckryall Oh I agree with you, I'm just saying you clicked to the wrong channel for that! Dave is the electronics snob of KZbin. And I'm not making fun of the Yahua either, I have 1 rework/solder station, 2 temp controlled solder pens, 1 DC lab power supply and a "Big Clive" 'lil USB power supply with Big Clive Mod! I also have 2 older Wellers when they were really good, and I wont spend anymore the money for the Weller tips. I'm sorry they are not noticeably better to me, I think I'd rather use the Yihua, so you will not hear me bashing them. It's also not like that thing should be left unattended anyway, even though that doesn't give an excuse for poor electrical safety, which does bother me.

[@MetalheadAndNerd]

You are right. Dave doesn't make much use of his equipment in these videos. If he restricted himself to power banks and LED lights the voice would be the only difference to Big Clive.

[@mjouwbuis]

I never actually measured it, but wouldn't a brushless DC fan always measure open circuit since there's a bunch of transistors between the supply an the stator?

[@fredfarnackle5455]

Precisely. A simple test by applying 24V DC to it would have been a definitive test. I have a similar station where the fan driver circuit failed, the fan itself is good and the hot air gun tests fine on an identical unit. I watched this video hoping to find out which component might be the culprit on mine but it was just a waste of time. The commentary really pissed me off, his high pitched squeaky non-stop voice is very irritating and he displays a contemptuous dismissive regard for what he is looking at and doesn't understand.

[@joeds3775]

Wow thats a lot of butt hurt for one soy boi. Firstly, give there were ONLY 2 wires to the motor... its not going to have transistors in it. Secondly, the price and cheapest option ethos kind of suggest a straight forward dc fan... And thirdly.. this guy is an expert who would have seen the truth in a reading of ohms that would have suggested another type. Your comments make you look a fool with little or no real depth of knowlege, and absolutely no respect. You are a muppet. And youre full of shit. Too full. Its comming out your mouth.

[@teardowndan5364]

While a 6A fuse may have been over-rated for the application, a more appropriate 4A fuse still wouldn't have changed anything about the hot-air wand melting down from fan failure as the element was likely operating normally at the time. The fuse only does any good when something fails in a way that causes excess current draw long enough to blow it. A bit puzzled about why the temperature regulation didn't reduce the heater's duty cycle after the fan stopped. Did the TRIAC or thermocouple short out? I know my similar-looking cheapo hot-air station is pretty quick at throttling heater power when I change airflow.

[@peterzingler6221]

And even this thing has a fuse WELLER!

[@kapioskapiopoylos7338]

i laugh but tbh this isn't even funny, my father and a good old professor on EE told me to get a weller as i am setting up my bench, then thankfully seen Dave's vid and got a hakko, they really made a name for themselves in the past that they do their best to ruin it now

[@westelaudio943]

Weller is a big fuse itself...

[@pauldegroot2405]

Weller has its fingers in its ears and yelling lalalalalalala

[@punker4Real]

Oversized fused so it's no better then the weller..

[@RetroComputerStu]

@@kapioskapiopoylos7338 The Hakko FX-888D is a great soldering iron for setting up an electronics workbench. I'd go for that over the Weller!

[@Akbar_Friendly_in_Cherno]

Use tape to get up the small sparkly bits

[@Seegalgalguntijak]

"sol dering station" is probably because the other side is "smd rework station" - they just separated both words after 3 and after another 6 characters. With smd rework, it fits fine. With soldering, it fits only after the second break, but hey, if you don't know how to read our characters, if you only know how to read Chinese, it would be just as hard as it is for us trying to write something in Chinese and getting it right.

[@pianoman78]

I think I would check with someone who knows Chinese before I print something that goes into production ;)

[@小卷卷-f1y]

No, English obviously has spaces in between words to prevent you from those mistakes. Chinese does not. And second of all, yes you`d think they would check at least for a minute before they put that on there. So that's still a retarded mistake and shows their general company working style which probably is the actual reason why that device failed the way it did.

[@discoHR]

My Atten 858D+ v3.0 also does the same thing if I have it in my hand (fan and heating element are working) and then press the middle "store/call" button. The fan stops working and the temperature shoots through the roof, smoke included. Took me couple of seconds to realize what's going on so I quickly changed the temperature which caused the fan to start again. Firmware bug.

[@BrucesWorldofStuff]

I have a 853D 3 "N" 1 and it has done the same thing twice and I figured it out fast and turned down the temp. Also if I have the little end on it [3mm I think] and the fan is turned down all the way it overheats for a few seconds and the temp sensor backs it down. So now if I am going to turn down the fan I also turn down the temp and it evens out as the set point when first started...

[@xXxbastek]

19:23 this fan is bldc, it have own driver on board. You can't verify it like that!

[@404Anymouse]

bldc wouldn't register as open

[@DVXCine]

I have a few of those fans ... They do not show impedance.

[@SteveMasonCanada]

I was yelling that at the screen when Dave came back and said it measured open. Surely he could plug it into a bench supply and verify.

[@jumilifyify]

Wait, can anything show as an open circuit and still do something when fed 5 V?

[@danmoos3635]

@M Rios Say that red wire goes to the gate of a controlling mosfet, or some sort of cmos input.

[@einfelder8262]

So as I am considering one of these as a hobby station for occasional use, the build quality of this seems sufficiently good. A fan burning out after 3 or 4 years of substantial use doesn't seem to be a show stopper, especially if one turns the unit off at the switch rather than flapping the red hot thingy around in mid air while wondering wtf to do, haha.

[@momoware]

These companies are tested daily by corner repair shops in China. They have to have some quality to survive the market.

[@lasersbee]

18:50.. Since so many of us have one of these WEP rework stations... why not get a functioning one and put it through some possible error conditions to see where it will/may fail ??? Then find a solution to the fail so what happened to David won't burn down our homes. Just quickly looking at it I can see adding a parallel reed switch to the opposite side of the hand held unit and perhaps a Thermal cutoff switch right at the element supply. BTW.. my 858D has been working flawlessly for the past 4 years.

[@wtfdinges]

I think you got yourself a fake one. I live in China and have a genuine Yihua station. The fan is supposed to keep spinning when you place it back in the holder, only the heater should stop. Depending on the starting temperature, the fan should keep spinning for a couple of minutes until the sensor measures about 50 degrees C. Also: the plastic shell looks nearly identical but the inside of mine is completely different. The PCB is different and the magnetic sensors (there are multiple in mine) are not simply glued to the housing. The heating element is replaceable as well.

[@igotes]

It even has the "traditional assembly display retraction" as in Yihua's "how to spot a fake" guide shown at the start of the video.

[@Wilson84KS]

Yes, some of the handles have the same plastic for the shell over the hot part like the rest of the handle, but most have a different, heat resisting material.

[@JFirn86Q]

Could it be possible there is a malfunction with the Triac? Don't know much about them, but wow, surprising it failed like that. Terrible!

[@MrZANE42]

That would be my guess also. Testing the fan should also have been done by applying power to it instead of measuring it's resistance. I don't think that's a valid test if it's brushless for example, or if there's a diode in series with power input

[@EEVblog]

There are several possibilities like that. They are usually pretty robust though.

[@Maverickx89]

I put my bet onto it too.

[@EEVblog]

That doesn't explain the failed fan though. Bit of a coincidence to get a TRIAC and fan failure at the same time, unless the fan failure caused the TRIAC failure somehow (I don't see the opposite happening)

[@Agent24Electronics]

My first guess was that the heater control triac went shorted, but if the fan had indeed failed then perhaps it's something else. If the fan died first, then my theory is that once it failed, there was no airflow to keep the thermocouple 'updated' with the real heater temperature for some time, thus the software did not notice any significant change and did not reduce the duty cycle. Because of this, the heater temperature increased very quickly. By the time the thermocouple tracked the actual temperature of the heater by convection, the temperature value may have been so high (in software) that it was 'out of bounds' to what the program expected, and thus it (the program) did not know what to do or ignored it completely. I wouldn't be surprised if a badly written program with no sanity checking or edge-case testing caused the runaway condition following some hardware failure, but at the same time, I agree with Jimmy Pedersen, a simple resistance check on the fan isn't that conclusive, so maybe it really is just a shorted triac.

[@HarmanRobotics]

Heat regulation keeps the output at a set temperature, if the fan fails the output temp stays the same but there is no cooling air to protect the plastic from melting. The heat which is normally carried away finds it way back to the plastic housing. Seems like a second temp sensor would be a good safety feature.

[@toddberg3892]

Harman Robotics Even some type of sanity check of the output duty vs sensed temperature- if output is too low, poor airflow is suspected, alarm and turn off output...

[@dimitris_verlis]

Or a thermal switch in the resistor for overheat protection

[@GeneralPurposeVehicl]

OR JUST PUT THE DAMN SENSOR NEXT TO THE HOT COIL INSTEAD HAVING IT 25 MILES AWAY. (Black insulation can keep your isolation.)

[@falmircamion3534]

I also have a 898D from another company, and one of the greatest dangers of those devices, is that they will start when removed from the holder, EVEN IF YOU SHUT THEM DOWN FROM THE CONTROL PANEL. And by the way, mine had no information sheet whatsoever to tell ma about this magnetic switch behaviour - which made me thing first that it had spurious restarts until I realised it was when I removed it from the holder...

[@BillAnt]

Could it be that the fan motor itself went bad? I'm surprised this has happened, since I have an identical unit which I've been using for over 10 years, yet haven't had a problem with it. The reed switch is a bit finicky, so care must be taken when putting the heating head back on the cradle.

[@LynxSnowCat]

My school outfitted their lab with 853D's (which feature the same heatgun, etc. + power "supply") I've seen a few of them meltdown in a similar manner. There's a software bug (in the 853Ds we had) : if you keep cycling it between active/holstered in a short amount of time the processor locks up and stays in a random-state {(fast) heating up, steady w/ fan, cooling off, off}. The workaround was to listen for the fan to shut off on holstering. If immediate then switch the unit off then on again, and don't leave anything heat-sensitive where the holstered heat gun is pointing. (Was actually convenient when shrink wrapping stuff.) OFC with sixty hot airguns to choose from, this wasn't a serious issue, unlike the input filters starting smoldering fires because of an inappropriate component choice(?) Those all got replaced/retrofitted before being installed so I can only guess what the TI changed.

[@ligius3]

That would be a good info to put into the 898/853 thread on the eevblog forum. A lot of the people have studied all the variants and started doing mods to make them safer.

[@Marzec309]

On my YiHUA 898 D+, when cradled the blower stays on until the temperature is below 100 and orientation doesn't matter. Features that Davids did not seem to have.

[@jacobdykstra8499]

It seems the triac or whatever is driving the triac failed. That's why the reed switch responded and turned off the fan and the temperature feedback sensor couldn't turn off the element. They should include a physical thermal cutoff switch near the element to prevent this.

[@debeeriz]

the fan does not stop when its on the cradle until it reaches 100 degrees so he should have known something was wrong as soon as the fan stopped and the degrees had not counted down

[@rarrawer]

Shouldn't there also be a last-resort one-off thermal fuse to kill power to the element if the handpiece goes above its operating range? I think they include them on electric kettles and things like that, with something like two springs joined by a blob of temperature-specific alloy.

[@MrHuno92]

7:10 because red color means where electrons are flowing from.... duh everyone knows that electrons are blue

[@fab672000]

Never leave the area when this tool cools down, keep an eye and an ear on it, a nice trick is to slightly increase the fan speed, and it should cool down more rapidly. Great tool for the price. I also often rotate the tool until i see temperature decreases...

[@InssiAjaton]

Thanks for an interesting post mortem! Just a tiny note from an ex cable manufacturer: Quite unlikely that you would find 8 strand wires. The geometries favor 1 center & 6 around, which equals 7. The next one, used for more flexible wires would be 19 strands, (1+6+12).

[@750SonyP]

Purchased a year ago. I found it did not always seat properly in cradle to shut down and no cable disconnect for the hot air rework like for the soldering iron. Definitely should never be left unattended, unless completely unplugged!

[@gglrb]

I do wonder if there may be something wrong with the position of the thermocouple. Because the way it is mounted it may just look at the temperature of the air around it, and not the temperature of the heating element. So if tried to keep the temperature of the air but if there is no airflow (if the fan breaks or ...), then it would overheat the element and still think that the temperature of the element is ok.

[@mirabilis]

Maybe a MCU brown out without a proper watchdog routine.

[@Zadster]

I think David nearly had a brown-out when the thing started to meltdown in his hand!

[@davidledger5941]

@@Zadster Accurate

[@gavincurtis]

Wouldn't suprise me one bit. Hastily compiled chinesium grade lazy slack-ware is in everything. 32K bloatware just for the SPI interface driver..... 5,458 clock cycles to execute 1 instruction. Embedded windows on an ARM chip to blink 1 LED... Use an external A/D converter because the slackware compiler tool couldnt use the internal A/D....

[@Buizie]

*_Yeehaw 898D_*

[@mattmoreira210]

I wonder why there is no thermal fuse to be found, though.

[@iuri.castro]

Probably cost reduction

[@JacGoudsmit]

@@iuri.castro They could have done with fewer connectors on that PCB to reduce cost

[@mattmoreira210]

@Iuri Castro but those things cost 50 cents tops, even cheaper in volume. I don't see how having a thermal fuse could impact revenue significantly...

[@phuang3]

Well, the entire handle is the fuse. When it melts down you buy a new one. It's dirt cheap in China.

[@David-ik9yn]

I sure hope that the white insulation material isn’t asbestos!

[@DrakkarCalethiel]

I'm curious what that material that is. I took out a thermal fuse out of my hot air gun and that stuff feels like some sort glass fiber

[@DrakkarCalethiel]

Ed Gein It is! If you google mica heater you get tons of results at alibaba

[@mjouwbuis]

It's mica. A naturally occuring mineral just like asbestos, but the flakes are quite different in shape compared to asbestos and aren't known as carcinogenic. Since it's so flaky, it isn't usually used as a wrapper. It may have been reinforced.

[@valerionappi7839]

Looks like mica + glass fiber to me

[@Phantom-darkness]

According to my book it’s a mica wrap. I have a spare heating element. It says do not remove mica wrap to avoid short circuits.

[@scotshabalam2432]

Bucket of Sand. It's old school but a bucket of sand is great for electronics fires like Dave had and it's not as much of a commitment as breaking out the fire extinguisher.

[@strayblackcatsmeow]

The thermal couple was properly located beyond the last coil of the output. But when the fan cut off and the tool was docked, it was at the bottom of the heat coil. As heat rises, the cool air is drawn into the nozzle passing over the thermal couple telling the processor to increase heat. Even if the thermal coupling was working fine, the heater housing would be kept far hotter than designed.

[@nor4277]

My auto shut of is starting to fail I put it on the holder a few times and had to keep playing with before it starting to work again.you can by replacement heat blowers on Ebay ,I may have to do that or replace the whole unit.

[@frabert]

The station I have right now is similar to this one, but when the handle is but back into the holder it instead turns the airflow to the max (in addition to turning the heating off), so I guess they have at least attempted to give it a better chance of survival...

[@Darxide23]

"Input fused. There you go Weller." Shots fired.

[@Sickma15]

I wonder how close this model is to the Xtronic 6040? They look near identical. I know i had this exact problem with the air gun on the Xtronic 5040-xr3, but i chalked it up as improper use because it was in a unmonitored student lab at at my university. Where some thought you melted the wires to solder something.

[@garthdaddy7438]

Power to the heater is switched off when the torch is in the cradle and the fan keeps going till the temperature falls to 200 deg, if the fan connection was faulty and the torch not positioned properly the heater would not be switched off result meltdown. The heater is regulated by the setting on the front panel not by the blower as suggested by Dave, the blower has a separate speed control on the front panel.

[@app0the]

That thermal sensor looks too far away from the actual heater for me. Maybe it wasn't registering anything faulty due to the low thermal conductivity of the ceramic base while the thing was already melting, and the missing airflow was supposed to be moving the heat from the coils onto the sensor, but obviously wasn't there to do that?

[@lorenzocimbro8055]

even if it has an overheating protection in software i think the termocouple was not able to detect temperature because of its position. It seems to be placed inside the ceramic insulation and in contact only with the hot air, so no air no temperature

[@proluxelectronics7419]

SCR went short hence the thermal control was lost. Also the fan has control electronics and cannot be measured as a coil..

[@BlackAmV0]

I have the same Yihua board based station. I've seen some stations burned by the triac, that's why I never leave the handle on the holder when the hot air switch is on. When I turn the hot air switch off its cools down also, but the switch is turns off the heater physically, not through the triac, that's why I'm sure my station won't be burned like this. I was thinking to put some additional relay protection in the station, which can switch the heater off when the fan is stopped, but I don't think I really need this now.

[@Usualexpertise]

one problem I noticed is that the temp probe requires airflow for proper sensing. it wouldn't explain this fail because it would have sense the temp before it went completely nuclear but it could be a contributor.

[@martinda7446]

Well and truly wellered.

[@volvo09]

Well said

[@beauslim]

I had almost exactly the same thing happen a few months ago. Same WEP brand. It was an air-only model. I set it on the cradle, and a few seconds later I heard a POP and my lights flickered. I looked over, and the whole metal part of the blower was orange hot. I am absolutely sure that the fan was still running. I hit the power switch immediately and unplugged the unit from the wall. There was no smoke or flame. I took the handle apart and there wasn't any noticeable damage to anything. There was a small spot up on the metal casing that *looked* like the heating element had shorted and created a weld. I took the chance and tried turning it on again in a safe location. The fan ran but the heater did not come on. "Fortunately" mine was only a couple weeks old and I was able to return it to Amazon for a refund. Looking in forums afterwards, I read some of the best advice for these: It's good for the price but only use it in the middle of your driveway with a fire extinguisher handy.

[@chrisg6597]

I see that the Mains fuse is wired incorrectly. The live wire should go to the tip end of the fuse holder, not the side contact. The way that it is wired, it would be possible to get an electric shock (through the fuse itself) during replacement of the fuse with the power on.

[@LarryDeSilva64]

I have a model 855D and mine has the soldering iron heat gun and a variable voltage supply. I bought it new off ebay for $89 and have used it the last 6 months and have had no problems whatsoever. It's possible to get a Lemmon every so often.

[@NikiBretschneider]

I am thinking of rewiring of my 858D. Mains switch should physically cutoff power from the heating element. I know, it means using larger switch. I have 858D for six years and have no problems, but I ran into similar issue with same optocoupler (optotriac) used here, which sometimes (and I do not know why) turns on and stays on despite the fact that diode part of it is unconnected and stays in this weird state until the triac side is disconnected. Then it returns to normal. It's rare, but it happens. I am using central switch to cutoff everything on my table, so the soldering station is most of the time disconnected from the AC, but it's not good feeling to know that there is only silicon switch (with weird optocoupler) between AC and heating element.

[@sonic2000gr]

I have the Atten branded one. As soon as you put the handle down, the reed switch cuts the power to the heating element and the fan keeps blowing until the elements goes down to 100 C and then stop. So even with a fan failure, overheating of the element cannot be explained as it gets no power when the handle is down. It would just take more time to cool off.

[@bavarianmonkey8326]

This is why I personally do never ever recommend cheap tools to beginners. When you do a review and show them that these things work and are usable, these end up in children bedrooms, hobby labs and all other kind of environments where an epic fail like this one cannot be contained properly - especially when the device is handled by an inexperienced person that has never experienced something going south that quickly. Those people might burn down their houses. Devices of such questionable origin should not be recommended to anybody. They are dangerous. I would have expected something like this to have two independent temperature sensors / cutoffs.

[@mozismobile]

no airflow so the hot air didn't get to the temperature sensor?

[@EEVblog]

Possible, but the sensor is close enough to the coil to still get radiant heat.

[@jesondag]

This exactly. There is not enough radiant heat to keep it from getting very very hot.

[@donkeytits1]

If radiant heat where enough to trip the control, then it probably would not work very well at maintaining correct AIR temerpature

[@rcmnet]

Radiant heat was enough to melt the plastic, also convection and the close proximity to the metal tube should have been enough to read the high temp

[@jesondag]

@@donkeytits1 It relies on the fan blowing the air to maintain temperature.

[@supersilve]

I could not see in the video checking the fan motor with a 24v supply. So how can you be so sure it failed?

[@SergiuszRoszczyk]

Maybe the algorithm was written to control minimum and target temperature but overheat due to lack of fan was a “should never happen” branch in the code?

[@shanepearce1629]

i have one of the ebay ones it has a temp up to 480 degrees and the fan will stay on until the handset is down to 100 degrees before shouting the fan off so it may have been just to hot with no air flow to cool it down

[@Turidus]

The way the thermal sensor is placed, without air blowing through, how accurate would be the sensor? Circulation and conducting are minimal, so the only major heat transfer would be radiance, right? Could take a while to heat the coupling up enough to trigger a shutdown.

[@randycarter2001]

The fan measuring open just indicates the electronics in the fan are not shorted. The only valid test is to power the fan up and see if it runs. It's a brush-less DC motor.

[@Equiluxe1]

It may be that the element continued to be regulated at an elevated temperature when the fan failed, the temp. sense is down stream of the air so when the air flow stops it only gets radiated heat which would make the device think the element is cooler than it is.

[@canadavey]

I was using my WEP 858D today and had a similar problem... Fan was on full, working at 385 degrees and the next thing I know the barrel where the heating element is was red hot! I looked at the temperature readout and it read over 700 degrees and it's max temp is 500! (all temps in Celsius) I quickly shut it down before it had a complete melt down like in this video. Needless to say a new hot air station is on order, not one of these though... Still going cheap but not super cheap.

[@SuperBrainAK]

there should be a temperature fuse in the heating element, should be rated for around 500C, so if the fan does fail the element wont get too hot. that is why my X-Tronic unit says to keep the fan speed knob above 5 for temperatures over 400C.

[@metricmine]

It's obvious based on David's description. He said the fan cut off, but not the heater. The fan is not supposed to stop when placed in the holder. It only stops when the temperature drops below a level, like 100 degrees. This means the fan failed, or a fault in the circuit providing power to the fan. The reason it overheated is because the reed switch was not activated so the heater remained on. The temperature sensor position measures the hot air blowing over it. Without the air blowing, there would be a huge temperature difference between the heater and the sensor.

[@felenov]

I use a WEP 952D+ as my main hot air station. The compressor ones have a protection. If it runs the heater but no response from thermocouple it throws an error and shuts off, also if it loses the thermocouple it throws an error and shuts off.

[@Unordung]

I had the same unit for ages, the fan on mine stopped working within a few years. I simply replaced it with a better quality fan. I since upgraded and gave the unit to a family friend. Who to the best of my knowledge still uses it.

[@unom5579]

when the fan on yours stopped working, did the plastic melt down like the one in the video? what replacement fan did you use?

[@RealPandaGE]

I have this soldering station and had what seems to be the exact same failure. The fan stopped working and the element would keep heating up. Luckily the reed switch still worked so I put it down and turned it off. After replacing the fan, the station is still working and in use about 3 years later... I think it might be time for an upgrade

[@irishguy200007]

So the fuse needs to be swapped out for a lower value? Did the user place the hot air gun incorrectly back into its holder? , I wouldn't have know that there was a particular way to place the wand back into its holder.

[@marsma18]

I think that termocouple needs airflow to have good readings. It is quite on the side from the heating element. and another aspect is cold side compensation. If it was not reading the correct value the hole device was lot hotter and the readings could be just a way off.

[@georgesmouchet774]

Got the same trouble on similar device. I turned air flow button to minimum (actually no air flow at all) but temp was set quite high (360°C). Just holding it by hand while talking to somebody, the thing went very bright red and the plastic handle melted. The fact is the heater start heating on the handle side, the end side was probably hot but not reddish and below 360°C, so I guess the sensor at the end of ceramic element without air flow is just useless in this case. Now I know it, and pay attention to always set air to max before hanging on.

[@neiliewheeliebin]

If you buy one of these make sure you inspect it internally before using it they're hit & miss assembly wise

[@richard7crowley]

If the fan fails, it won't push the heated air over that thermistor at the front of the heating element. So the sensor is not representative of the actual temperature.

[@uK8cvPAq]

How come the fuse is rated so high? Could they be using a 220v transformer on 240v running it into saturation?

[@Boz1211111]

I had something with almodt the same handle but it blows until it cools to 80c before shutting off

[@gtragle1]

I think what happened that the fan stopped working and the sensor detected the temperature increase so it set the heater to the lowest setting but without air flowing it wasn't low enough because it probably wasn't programed to deal with a fan failure.

[@GeneralPurposeVehicl]

It looks like the TEMP sense was not properly coupled to the heater without airflow, as that looks like a thermal insulator type core.

[@MasterAlexei1]

Every soldered (not crimped) wire will brake exactly on the line of solder tin from a even a little vibration. It is just a question of time here.

[@Garbaz]

Might it be that without airflow the thermocouple doesn't get enough heat, since it is so far away from the heating element, causing the regulator to shoot up?

[@robroysyd]

It could have been nothing more than dust blocking the openings in the handle, seems likely given it happened just after a move. The issue I see is the thermocouple measurers the temperature of the air flowing over it. No or restricted airflow means the thermocouple is heated less and more of the heat from the element goes through the fibreglass overwrapping into the plastic case. Could have been avoided with another thermocouple or thermistor measuring handle temperature to trigger an ESD state.

[@electricsnut]

The thermal sensor relies on the air stream heat it and to regulate switching current to the element. With no air stream it cant read the temperature accurately and ramps up continuously. The ceramic will insulate it if anything. There should be a failsafe thermocouple or other measure inline with the element should there be a control failure. Im surprised that crappy sleeve bearing fan lasted 3 years.

[@gregsmith9183]

We also have the genuine YiHau 898D+ workstation.Had it for many years. We mainly use the soldering side of the setup. Touch wood nothing like this has happened to our setup yet.

[@ThinklikeTesla]

The 120V version has the same 6A fuse. It's probably something they didn't bother to change between 120/240V models.

[@reaperreaper9593]

I have a similar one and mine doesn't turn off the fan until the temperature of the heating element is at 50C or less. The fan died once, though. Turned it off, swapped the handle and is still working to this day.

[@dhpbear2]

11:40 - Maybe the fan was indeed wired backwards (reverse direction)!

[@DreitTheDarkDragon]

Isn't thermocouple just too far away from heating element? When no air is flowing, then I guess just part of heat will get to thermocouple. It would be great if there was some kind of pressure (air flow) sensor like in industrial gas burners - when fan fails, solenoid shuts off gas inlet.

[@grapsorz]

do any product connect N and ground? here both is live so that will be catastrophic.

[@dimitris_verlis]

I think the problem is due to the position of the thermal sensor, it is far from the resistor and when the fan broke, read less temperature than the actual temperature of the resistor!

[@debeeriz]

also you can get a model that does not countdown and stays at the set temp or you can modify your unit so it does not switch off when on the cradle which this one may be, as the reed switch should have turned the heater off

[@jkbrown5496]

Those things are a bit of an adventure. Not for hard use. I bought one, not sure specific name, of just the hot air. Tested reasonable on the fusing and ground, but not upon closer examination. For one thing the neutral was switched, so I swapped that around and ran better ground wires. But they work by fan cooling down to about 100 C. If the fan failed, even if the element shut off, that heat that is usually blown out was trapped and could only go into the plastic. Incident sounded like smoldering plastic, which you can get from just heat dissipation.

[@John_Ridley]

I have a cheapie, and when I holster it, it turns the heat off but the fan runs until the temp sensor reads below 100C.

[@stevetobias4890]

I use a WEP 853D solder / rework station that includes a power supply and amp tester up to 1 amp. I read that you need to make sure to turn it off at the rear main power switch and not leave them switched on even when the hot air switch is turned off. The hot air guns are reported to fail after long periods of use. It works well for me but I take precautions and dont use it for extended periods. I cannot afford a high end station just yet but will down the track. Maybe upgrading the fan is a move in the right direction until I can effort a better one (and crimping the earth wires & lowering the fuse rating).

[@vincei4252]

David and Dave, well now you have a transformer for that Weller. WEP and Weller colab. 😂😂😂😂

[@wolvenar]

Wrong voltage (s) out of this one I believe.

[@wolvenar]

But it DOES have a primary fuse. LOL

[@vincei4252]

@@wolvenar IKR 😂

[@Zadster]

Unfortunately, as we have seen recently, buying a premium brand is no guarantee of safety or reliability. They all seem to rely on one component in the protection system. If that fails then you are stuffed.

[@scootergeorge9576]

Where does it start spewing flames?

[@SparkyLabs]

There will have been significant heat build up after hours of use and the fans probably cut out too soon. I set mine to minimum flow when I put it back so that the heat has more time to dissipate from right inside of the thing. A fast fan flow would cool the surfaces and then shut down with more heat to be released.

[@greypaladin4560]

I've got one of these that's so old it doesn't even have branding on it (there's a blank space where a logo would go, and the model code 898D+). I have no idea if it still works since I rarely ever used it. But thanks for the warning, I'll be sure to make sure it doesn't go supernova whenever I use it next.