EEVblog 1481 - Dodgy Dangerous Heater REPAIR

[@AndyFletcherX31]

The cable trapping is a product recall job. If you feel enthusiastic then send photos and report to the big box store. Their lawyers will then trip over each other in their attempts to avoid liability by issuing a product recall.

[@EEVblog]

Arlec have been contacted with a link to the video, will see what their response it. I will have access to another one of these heaters next week so will check that one also. Also contacted Bunnings, but it's one of thos stilly web form things, so will see what happens there also.

[@MendItAussie]

@@EEVblog Hi Dave, we both separately watched this gem of a repair video. Danny to pick up some tips and tricks if any, and Karen to assess the video for relevance to #righttorepair. This product's teardown for inspection and assessment of a fault is an alarming example of why we need the new Federal Govt to get cracking on the Australian Productivity Commission's Right To Repair Inquiry report. We need legislation that prevents poorly designed products from entering the country or being manufactured on-shore.

[@gracjanstanosky9698]

@@EEVblog What kind of people use a heater in Australia 😉

[@brumbymg]

@@gracjanstanosky9698 The kind that want to keep warm and either don't have the budget for reverse cycle A/C or are in a rental property. Central heating is common in Melbourne, but not generally a thing in Sydney. Sydney can get down to 0ºC in Winter. I've already had a couple of mornings this month where I found the bird bath was an ice-skating rink.

[@zebo-the-fat]

@@gracjanstanosky9698 Cold people?

[@sysghost]

If there's something I've learned with all these EEVBlog videos, it is that my uncle is named Bob. And that stuff is flapping in the breeze.

[@nicwilson89]

18:58 Oh that is a beautiful sight! A proper electronics store that sells actual component...we lost all of ours in the UK so now the only option is order online and pay shipping :(

[@PracticalCat]

Yep! I am very grateful to have Jaycar and Altronics here in Aus. So good when you need the odd part or for a small project!

[@FlyingShotsman]

Same here in America. The only national chain we had was Radio Shack (Tandy), which started pushing components out of their stores years before they went out of business. All we're left with now is a few independent stores in major cities, most of which are largely surplus operations with very little new-production stock. I'm grateful that Digi-Key offers flat-rate shipping for $5 on small orders so I can usually get parts in a few days.

[@PracticalCat]

@@FlyingShotsman we had Tandy and DickSmith here. They both went the way of radioshack.

[@hermannpaschulke1583]

Same here in Germany. Conrad was the last chain and they closed all their stores recently.

[@nicwilson89]

@@FlyingShotsmanYea, we had Radio Shack. It changed to Malins and slowly started selling more and more cheap shit electronics such as cheap speakers and disco lights and RC cars and less and less components until they all were removed...and then Maplins went out of business. Such a shame because Tandy/Radio Shack was great originally

[@buddysnackit1758]

What I like about you Dave is that you show your mistakes. It was understandable and gives your videos a "real" feel to them.

[@dentakuweb]

Repair videos of very simple electrical appliances like this are a good way to explain what the jellybean parts you see every day do. Big Clive has pretty much made it his job.

[@gnif]

I literally repaired an Aldi electric blanket controller last week for my parents that had the exact same failure, and used the exact same larger part. Had to explain to my dad why it was important we use an X class capacitor instead of another with the same rating from his parts bin. Sunbeam are also notorious for using capacitors that are under-rated on the voltage to ensure death of the device (you will need to google this, great writeup on it but YT yeets my posts if I put a link in them).

[@fiddlerJohn]

Good to know. Thanks gnif

[@detalite]

Few months ago i repaired Yamaha RX-E810 amplituner. It had capacitive dropper standby power supply. Capacitor had like a 20% of original capacitance. To speed up repair i was looking through my used part bin, and almost all had the same issues. Finaly i found in old LCD TV power supply a 1600V beast with factory spec capacity. Month later same problem in water heater.

[@LogiForce86]

@@detalite I am suspecting someone is creating and integrating these failure points on purpose, cause it happens far to often to blame it on Murphy. 🤨 I also have a Yamaha RX-V450, and also has the 22nF/630V polyester film capacitor in it that went bad. Replaced it with a Wima FKP3-22NF-630V Polypropylene Film Capacitor, which is what the electronics shop had on stock and would be a better part for the application he said. Works a treat!

[@erikdenhouter]

And think about that Dave found an EXACT matching cap in the bad PC PSU, and.... faulty too.

[@erikdenhouter]

@@LogiForce86 Murphy is a beast that can be fed.

[@theraiderra8798]

I love repair time! Difficult to repair most things nowdays with everything being integrated into one chip... but you always learn something.

[@ZylonFPV]

19:10 - Dave destroys an entire line of JayCar’s caps

[@derekloudon8731]

As per Nic's comment, we in the UK have lost all our "walk in & drool" electronic component stores 🩲 I used to love walking into Maplin and browse for ages getting ideas (my wife was very tolerant as I am when we visit a wool/craft shop). Yes, we buy on-line but it's not the same. Walking around looking and touching the components can often change the direction of your project (usually for the better).

[@zos8085]

This makes me cross. Plenty of bead/wool shops. It makes me think how long the Singapore electronics towers will stay alive. Mind you when that happens - all electronics and jobs etc move to China - with the design jobs as well. I expect the thin surface mount bridge rectifiers to be the next wave of culprits. (along with composite ceramic smt capacitors).

[@zebo-the-fat]

I love the high quality metalwork in this product!

[@Thermalions]

Being an Arlec product I'm kind of surprised they didn't mount the element higher and make the base out of plastic.

[@longrunner258]

​@@Thermalions No imagination necessary there; my Mum had a Goldair Turbo-Convector heater (model 8050) with plastic *top* grilles. Because that's totally a sane thing to do in ≈130°C convection currents, isn't it? At least I've not seen that practice anywhere recent.

[@zaprodk]

The x-class caps do not blow up, but it's quite normal for them to lose capacity as the wear mechanism. The metallisation on the foil is slowly eroded away.

[@MomirPeh]

I'm suspecting that it's a metallized film cap and it has self-healing properties when the dielectric fails. The self-healing is going to do its thing by burning off the metallized film in the area where the dielectric has broken down and it will no longer be a problem and the cap will continue to be a cap. But, the capacitance will go down slightly due to the metallized film area that was lost in the process. That particular cap seems to have suffered a lot of such events and it has lost a lot (roughly half) of the electrode area... I'm wondering how that cap looks inside now :) BTW, I've had these caps failing in such way in a lot of the equipment that uses it for either filtering or as the dropper component. Edit: I didn't watch the video to the end when I wrote this. :) Dave did mention that it's a self-healing cap...

[@davidmaiolo]

Nice analysis

[@Rob2]

Yes, I wanted to reply the same thing. A "self healing" capacitor does not have a capacitor factory inside! Every time it heals, it loses in capacitance. This is actually a very common failure in capacitive-dropper circuits, often shown on the other "youtube electronics" channels. I was actually amazed that Dave did not know that.

[@rocketman221projects]

That's what happens when they self heal. If you measure any X capacitors removed from old equipment, the value will almost always read low. When they are used as a filter capacitor, most people won't even notice that they have failed unless the equipment starts interfering with something.

[@petehiggins33]

Yes that's exactly what happens, Ive seen it numerous times. I always replace them with the next voltage rating up which is 300VAC here in the UK. Another consequence of this is that X class capacitors which actually are across the mains for EMC filtering purposes become less and less effective as the equipment gets older just like that one that Dave found in a computer power supply. In case you haven't twigged, "Polly put the kettle on" is Dave-speak for metallised plastic film capacitors, as in polyester, polypropylene etc.

[@victortitov1740]

i think it's some sort of electrochemical corrosion going on. As true as you are saying that self-healing is expected to reduce capacitance, self-healing is supposed to cover the rare case of a manufacturing defect going thermonuclear, and not be something that can eat half of the electrode area. It's almost as if it is designed to gradually fail... but it's so common, it's probably just a problem with compromises made to achieve self-healing (electrodes are too thin?).

[@ThriftyToolShed]

I had a Kill-A-Watt meter that was reading incorrectly due to a similar failure. Replacing the cap was the fix for sure and I have a video of that repair. I was surprised how expensive these X rated caps are and like you mentioned it's best to keep boards around for parts. Like you I did not have the exact one on any donor board. It's sure handy when donors work out! Great video.

[@ESS1024]

X2 caps on donor boards are usually already semi-dead.

[@bloodybucket213]

I've got a 'not'-dehumidifier in my basement that's getting a second look-at this weekend. Thanks Dave.

[@fabiotrevisan8922]

Great repair video there Dave, as usual I should say, but as you went through, you referred to that 47R resistor there, several times as a "dropper resistor" and, as though we can't say it's wrong (all in all it's in series and indeed "drop" some voltage), this IS NOT its intent on this kind of circuit. Sure enough, it's meant to be an Inrush current limiter, to prevent a high current peak when the "dropper" capacitor is discharged and you happen to connect to the mains while it is at the peak voltage. As it turns out, the impedance of the capacitor, being a 220n @ 50Hz, is around 14.5 kOhm so, a 47R resistor can barely drop anything. On its turn however, maybe this resistor being so small can be exactly the explanation why the capacitor failed, because being so low in value, the inrush current on the capacitor will be gigantic. It could have been very well of 10x its value, and the inrush current would still be some 30x the nominal current. Granted, 470R would drop a little bit more voltage and would maybe require a higher power rating resistor, but would be a little bit more sane.

[@TheDigitalAura]

You're so lucky to have such an awesome electronics store so close.

[@scottpelletier1370]

That was my first time seeing it. Looks amazing and wish I had one around here (New England)

[@KGE64]

In the Netherlands we call this capacitance loss 'the Senseo Syndrome' because almost all Senseo coffeemakers suffered from this problem. I can not count how many devices I sent for repair within the warranty period (!) When older than two years (aka out of warranty) I just replaced them myself. I lost count how many :-)

[@WizardTim]

Can confirm all the -best- worst stuff is made by Arlec, but they're dirt cheap, I'm tempted to do a video looking at a pile of failed or DOA products that's Arlec branded. Those capacitors fail quite often in cheap capacitive droppers, I've have had it happen to a PIR sensor and a watt meter. They're probably one of Clive's most common repair items as well, he's even got a good video where he explains the degradation failure mode in his notebook. Also I don't think you ran DRC in your DaveCAD circuit, shouldn't ZD1 and ZD2 zener diodes be essential on the diode bridge output across the capacitor to clamp the rail to 24 V?

[@EEVblog]

Yep, completely forgot about ZD1 and ZD2, my brain rejected them.

[@mmghv]

To my understanding, the zener is the responsible for the output voltage, the capacitance only provide the current, I calculated it to be about 16mA for 220nF, but with less capacitance the voltage drops because it can't provide the required current.

[@ReginatorNet]

Sweet - after watching this, I learned something about X and Y class caps!!

[@brainndamage]

I saw this exact failure a lot. Most commonly in PIR motion sensors, and even in a plug-in mains power meter. I suspect they use lower-voltage rated caps and label them as higher voltage. They work but are right at the edge, and over time voltage spikes will destroy enough foil to make them go bad. You can also see that a properly rated X2 cap is a lot larger for the same capacitance and voltage.

[@bigjd2k]

You can use class X1 caps for much better reliability, but they cost more & are a bit bigger.

[@liam3284]

Another place I saw them fail was as run caps in sunon fans. Good fans, let down by terrible caps. Replaced them with X1 caps.

[@Spark-Hole]

The company was cheated by buying the cheap cap.

[@greengrayradio1394]

The series cap has had a breakdown caused by a voltage spike, healed, and now has a too low capacitance to drive the relay. It has done its job as a safety X2 component

[@aerobaticant]

Hi Dave. I've seen many failures of capacitors in this type of circuit. Particularly on the control PCB for my central heating boiler. Also in a Philips branded LED night light. As soon as you said the relay wasn't energising, the series capacitor was my first suspect! I wish we still had electronic component shops like Jaycar here "back in the Old Dart" :-)

[@artursmihelsons415]

Great troubleshooting and nice repair! 👍 That's completely normal to overlook something at first tests, especially, when working without schematic diagram.. 😉

[@StuartCGadgetRev]

I found that strangely interesting! Cheers, Dave.

[@jonelectronics510]

Wish jaycar was in the UK! Love the old style component shifting.

[@SystemX1983]

About 20 years ago, I can remember I've been in a small shop stuffed full with shelves of any part you could imagine. Unfortunately I can't remember exactly where it was in the city and if it still exists. Maybe I should ask my dad, he knows that city like his own pockets 😁. But most probably the owner died years ago or the shop closed for whatever reasons 😣. Sometimes I wish good ol' times back... who would order a single resistor on amzn for a repair? 🙈

[@jtveg]

Great work Dave. BTW, the lack of a comma in the title of your video implied that your repair was "Dodgy and Dangerous", but I knew this couldn't possibly be right. Lol. Thanks for sharing. 😉👌🏻

[@Stoneman06660]

We bought a European brand name panel heater with a similar form factor to the Bunnings number, and it work a treat (they are really good heaters IMO) for about four or five years before failing. After a bit of troubleshooting it turned out to be the supercap that provided the power to store time, timer and what not settings that had failed. Once replaced it was good as new and is still going strong three years later. Winner winner!

[@Blitterbug]

Love your fault-finding vids, Dave.

[@abeleski]

love the repair videos. Thanks Dave

[@spirov92]

A few years ago I repaired one that used an optocoupler and triac rather than a relay for switching. It had failed closed and was running all the time. My first suspect was the triac, but it was actually the MOC3063. Diagnosing it was a bit easier because it had power and serial pins on the side (probably for programming it in the factory) that allowed me to safely power it.

[@MattyEngland]

It was an interesting one indeed. Cheers Dave

[@Foobar_The_Fat_Penguin]

Thanks for that video! I had a similar problem with a control board for a fan: The power supply was hiccuping when you pushed buttons, and I couldn't figure it out (I'm just a newbie). After your video, I revisited the PCB, and sure enough: The X2 cap that should have been 1 µF was down to 190 nF. Unfortunately, no Jaycar for me. I'll have to wait until my shopping list is big enough for me to order online. 🙁

[@janglestick]

This is great, I'm still figuring out why but somehow this video hits right on the mark for reaching both electronics learners and advanced people doing real repairs, and basic understanding of fixes and fundamental electronics and component replacement and reasonable upgrades .. what else ? not sure but something is great about this video, more like this !

[@techalyzer]

19: 00 - OH MY GOD, is that like a full sized hardware store, but for electronic components??? That is not a thing here, I totally want to visit one some day! :)

[@Philip8888888]

Thanks. Really interesting look at how to troubleshoot basic failures. I would have never figured this out except bllindly suspecting the capacitor (since I saw so many capacitor failures).

[@LawpickingLocksmith]

Lol, Arlec! Had one of their chainsaws that K-mart kept on exchanging on me. 1 Mango tree, 4 Arlec saws. Lots of smoke, lots of fun!

[@robvandeschepop8595]

Our Philips Senseo coffee maker had similar problems. This resulted in very small cups of coffee :-) The X2 class capacitor used in the power supply (brand DAIN) was bad. In my case the 470nF value was degraded to 105nF.

[@SomnolentFudge]

That pretty dodgy but I'll one up you. Just finished fixing my brand new heat-pump dryer (would have cost 1400usd, store gave us refund and let us keep the broken unit). It turned out to be a broken wire in the starter winding on the drum/fan motor. They used aluminum wire for the windings (coated with copper colored enamel of course). The dryer didn't even detect an error, nothing to check the drum is spinning it just sat there thinking it was working. The control board runs an arm core micro that will yell at you if the lint filter isn't fully seated but it can't detect the drum motor spinning. It is a whirlpool W11184587A if anyone's curious.

[@jaycee1980]

Whirlpool are a good example of a company that once made excellent appliances, but now make cheap junk engineered to fail

[@robertbackhaus8911]

@GsaUce Rug They've been around for ages. I've got a decades old microwave oven transformer downstairs with copper-clad aluminium windings.

[@samuelcolvin4994]

What's become of Amana and kelvinator😭

[@jaycee1980]

@@samuelcolvin4994 kelvinator was bought by Electrolux in 86 and only a name since... as are many known brands now

[@echothehusky]

Class X caps in this position fail so frequently in cheap domestic appliances that I keep a large stock for appliance repair!

[@BenHeckHacks]

That heater is certainly the duck's guts, come-a-gusta!

[@cultphetus]

Great content as always. Love this channel and thanks for always keeping me interested!

[@teardowndan5364]

You have never seen an X-class cap fail open or with reduced value? That is specifically what X-class caps are engineered for. Since they are typically connected directly across L-N where they are exposed to the full brunt of power line surges, they are designed to "self-heal" by isolating areas that got damaged by dielectric breakdown events to avoid causing a L-N short.

[@EEVblog]

We have a very stable mains voltage here, surges are rare. In fact I dont recall ever having a product fail at home or work or the lab due to a power surge. Happens all the time in other areas like the blue mountains west of Sydney for example, which is where this actual heat came from BTW. So that's probably why I don't recall ever seeing one lose this amount of value before.

[@teardowndan5364]

@@EEVblog Well, you did discover one that had lost an even greater fraction of its capacitance while looking for a donor part in your dead PSUs inventory, so that makes at least two in one repair session. I bet there are many more around you, you just don't know about them yet because dead X-caps used for EMI suppression will go unnoticed until someone with an EMI-sensitive device comes by, notices, files a complaint about it and you find yourself on the receiving end of an investigation.

[@beamfinder8336]

to see how easy you can buy parts at jaycar @ 18:50 and that they trust you not to steal a cap or resistor, I suddenly realzied that my country is not a high trust society anymore. In the shops here you have to go to the person at the counter and tell them what you want, then the person seal packages your stuff. I'm jealous. I'd take my GF with me, only to torment her like she does to me with clothes shopping :-P

[@jhonbus]

Haha, I was thinking the same. We don't have any shops that sell components like this any more in the UK but back when we had Maplin you had to write down the catalogue numbers for everything you wanted and then take it to the special nerd counter (not the normal purchasing counter) and they'd go and get the stuff for you. (Or more likely come back and tell you several of the critical items were out of stock so you'd tell them never mind, put it all back I'll go online instead. Wonder why they went out of business...)

[@czarodzi9967]

19:15 I'm sure the staff was thinking to themselves "this is the last time we let that KZbinr record in here...."

[@theoloutlaw]

I miss these video's, my favourite :)

[@tomgeorge3726]

Hi, Dave, great video, not to good a heater, bit of a surprised for Arlec. The X2 failure I have come across in many industrial controllers like that, they have reformed too many times after punch through and eventually the capacity goes down, I'm surprised it got so low in value before causing a problem.

[@Fluxkompressor]

You always get me with all that ausie stuff. April fools is one day early, its winter when it is summer, hot snow falls upwards (That's a Simpsons reference) And I sit here in my office at 35°C (95°F), wondering why Dave is repairing a space heater

[@GregM]

Just wondering if the dodgy cap was the cause of that PC pwr supply failing.

[@EEVblog]

No, it's just an input noise flter cap.

[@BG101UK]

I was racking my brain to remember which item(s) I have with that branding. It's my plug-in doorbell sounder unit, which has gone rather quiet. I just assumed it was the muck buildup in the back of the speaker (maybe some iron dust from when I was doing some grinding) but after seeing this, I'll definitely be checking for a dodgy cap. As others have commented, this is when you need proper electronics stores. Online only in the UK now, as far as I know. Maplin went maybe a couple of years ago and I think that was the last one.

[@Vladimir-hq1ne]

Very useful video, thank you! Problems like that with same X-caps are frequent in the cheap UPSes.

[@conker42]

Hey, you said it yourself, your yellow X class cap wanted to join the most popular 100nF club 😝

[@philkipnis740]

Winner.winner... You're the hero🎖️

[@pietpaaltjes7419]

That Suntan brand really does instill confidence in that cap 😁

[@danwei41]

I wonder what the cap is gonna look like from the inside. The color has a weird faint compared to the others.

[@ulfg1409]

Fixed the same issue in a kitchen fan controller a few years back. In that case the power supply issue was quite obvious, when you did anything that consumed power (i.e. activate any output) the LEDs went dim. More outputs active, less light from the LEDs.

[@marvintpandroid2213]

The most expensive part of the product is the box it comes in.

[@frosty129]

Cool repair, I find it interesting you are repairing a heater in the summer :)

[@Scrizati]

Australia is in winter ;)

[@zebo-the-fat]

@@Scrizati Upside down season syndrome!

[@jhonbus]

🤦‍♂

[@petersage5157]

This kind of repair is why I watch a variety of electronics channels on KZbin. Big Clive would have gone straight for the dropper capacitor. As Dave mentions in the follow-up video, these capacitors are notorious for losing value in this application.

[@PapasDino]

RIFA madness was the first thing that came to my mind when you showed the PCB! Guess I get a "No Prize" for that (any Marvel Comic collectors will recognize that!).

[@peterides9568]

Oh, this just jogged my memory. I've seen this failure before- There was something I used to see a lot of when I was doing an appliance repair job at a university... Might have been a heater-stirrer or something? They were using a R-C divider, and they were using an X2 cap as the "C", just like this heater. Those units would present with no display/controls, as I recall. My theory (with no evidence to present) is that in heating applications especially, the cap gets too hot and drifts low. Good video Dave, love some good basic fault-finding :-)

[@ray73864]

I find that with my local Jaycar too. They can often be close but not necessarily close enough, or they are just frequently out of stock of the ones I want. When I recapped my NES, the caps for the RF modulator were a rather tight fit and needed to be bent over a bit just to fit, despite being the correct ratings. Obviously they can't stock everything, but I like going there since it's either a 20min drive into town to the local JayCar, or a 4 week wait for AusPost to realise that they are actually a post/parcel delivery company to go from the eastern side of Australia to the south-western side.

[@KeritechElectronics]

3:20 holy shit, WTF?! Nice repair and explanation on X and Y capacitors.

[@JAKOB1977]

your definately bold rolling with such ultra-low CN heater gear on Aussie mains.

[@PhillipRhodes]

My question is, now that this thing is "repaired" are you going to continue to use it, or is it going straight to the bin?

[@EEVblog]

I expoxied the feet in place to make it a bit sturdier and it will go back into service.

[@robbieaussievic]

.... Safer now than it ever was !

[@180044suomi]

Better than factory!

[@jaycee1980]

Caps in capacitive droppers do fail, as part of how they "self heal" is just to arc away where it shorts... which leads to a drop in capacitance. Happens even to the good quality ones, never mind the el cheapy Chinesium ones!

[@urlkrueger]

That heater sure looked like a textbook example of "How cheap can you make it".

[@MetallicBlade]

Basically, modern appliances in a nutshell.

[@brucepickess8097]

@@MetallicBlade I think you'll find that a nutshell would have been stronger than that woefully thin metalwork.

[@izimsi]

If they wanted to make it cheaper, they would just use a mechanical thermostat - it would be less prone to failure too. I don't know why did they even bother to make the PCB and all that sort of jazz, when everything you need is a thermostat and a switch instead.

[@180044suomi]

@@izimsi Columbus gave marbles to the natives in exchange for their gold. Today you need a display to get mankind‘s money!

[@robertbackhaus8911]

@@izimsi Not these days. The mechanics of a thermostat is difficult and expensive to make - much easier to pair an off-the-shelf controller with a stock cap dropper power supply. Besides, it might break down after 18 months and you can then sell them another one!

[@yoksel99]

Aha, it is winter in Australia these days. Time to get heaters :)

[@Rob2]

Yes, always funny to watch when it is 25C outside...

[@dmsaintrain]

Hi Dave! Fun video. On the PCB, what are the solder "dots" for? Thanks, Doug

[@VK6NK]

I'm going to go back and investigate my dodgy heater now. Had a similar symptom, although if left on long enough (ie for days/weeks) it would eventually turn on.

[@WeFixTvs]

Great video, Thanks

[@LogiForce86]

"Focus you bastard!" ... Australia's way of saying AVE's Canadian line "Focus you fuck!" 😂👍

[@budgiefish]

Probably more common than you think - caught a couple of these caps failed in the last couple of months, both in capacitive droppers, both energy monitoring meters as it happens (different makes), as well. The larger one you used will probably outlive the heater! I believe the self healing properties (from voltage spikes?) results in the reduced capacitance, and there's not a lot of headroom with 220nF when 100nF results in practically half the required voltage at the requisite power draw, maybe a 330nF (or larger package) would have been a better design choice, but that probably could have cost 0.03p more :)

[@brainndamage]

One other thing I thought about. You found that X cap in the PC power supply was completely dead. What would cause that? What do PCs often get connected to? An UPS. What output waveform do all cheap UPSes have? (Modified) square wave. AFAIK there is no current limiting for when the transistors in the UPS switch on. The current spikes that would be caused by connecting a capacitor across the square wave output would only be limited by the wiring resistance, inductances (transformer, common mode filters) and battery impedance. Everyone using a square wave UPS to power their equipment may be unknowingly damaging it.

[@nophead]

I think it is common for X2 caps to lose capacitance over time. I think it is due to the self healing mechanism. I had to replaced one in a doorbell that was used as a dropper.

[@jhonbus]

Yep, the self-healing works in part by using a very thin metal foil as the electrode that vapourises if there's a short. So every time it happens your electrodes get a little smaller and the capacitance goes down. But if it's happening often enough to cause a noticeable drop in capacitance over a fairly short time, it's a sign it wasn't well-designed in the first place. Probably a dielectric layer that's too thin, which allows the whole thing to be smaller and thus cheaper. I note that those cheap ones that had both lost most of their capacitance (assuming they were anywhere near it when they were new!) were significantly smaller in volume than the presumably good one bought from Jaycar.

[@nophead]

@@jhonbus Yes they looked too small for 220nF. I wonder if it really needs to be X2 in this application. It isn't directly across the mains and the current is small, so a fuse or fusible resistor would stop it going bang if it failed short circuit.

[@kyoudaiken]

I'm at 10:00 and I think it's the capacitor for the capacitor dropper circuit for the relay power.

[@khronscave]

Yamaha used to have an odd mains-transformer-and-capacitive-dropper standby supply in some of their AV receivers and soundbars (and they still might?). Film cap loses (enough) capacitance, standby supply craps out, and the thing won't turn on anymore. I fixed a soundbar for someone a few years back, with this exact issue.

[@tdtrecordsmusic]

way cool ! omg sooo jealous u have a jellybean shop ! There are ZERO places to buy components around me :( RadioShack had bins, then one day they didn't. That lasted 10 years. Now the shack has bins, but they are barren/empty af. You'd be lucky to find a wire.

[@davenz000]

If not for the Utoobe revenue, would it have been worth opening up? What's the deal with the Aussie (and NZ) brands, can they be trusted for electrical safety? Arlec power boards / HPM etc. Seems like the consumer protection people should be taking a look at Arlec.

[@stewartbrands]

Nice wheel support.ha ha ha. Masterful engineering. ha ha ha. Love your reaction to expert work like that. hilarious.

[@FJL4215]

I have a box here of X caps pulled randomly from different pieces of used equipment. They ALL read low capacitance. Exposed to mains spikes they do their job and self heal without exploding but they do this by loosing capacitance. Some component manufacturers even say in the datasheet cryptic things like "do not use in capacitive dropper circuits" probably to avoid liability when this happens and the equipment doesn't get enough power any more.

[@Vladimir-hq1ne]

@4:20 - that's why I disassemble and reassemble any equipment from China. Cause... Too much fire hazard otherwise. edit - roasting electrical mini-oven where wires were clamped onto inside case not outer one, for example. Rerouted wires, added some old good (banned) insulations sheets - and that's golden.

[@MiniLuv-1984]

Troubleshooting, propose a fault scenario, test for the proposed fault, rinse and repeat. While you are fixing the electronics, you might as well bolster the legs with a couple of plates cut out from one of those dumpster PC's.

[@MyProjectBoxChannel]

I've often seen these capacitive dropper power supplies fail. It seems that the foil cap loses its capacitance over time. Possibly due to stress from transient voltages.

[@johneastmond9092]

A repair video! How many years does it take to get to these? Not for lack of trying.

[@VoidHalo]

I had a small 1500 watt space heater a few years ago I bought refurbished from a local electronics store. The one night I had it on while my room was pitch black and I noticed glowing red light inside where the heating element was. I was half asleep and just thought it was an LED or something. But when I glanced at it a minute later it went from red to white and I realized something was burning. When I opened it up the next day I could see one of the spade connectors was completely melted to its connection and the insulation all along that wire was melted and burned. Really scary that if I hadn't looked at it at that exact moment it would have caught fire. The really scary thing about it is I owned it for less than 2 months and had only used it for 5-10 mins at a time 3-5 times a week to warm up my bedroom at night. So it probably had around 5 or 6 hours of use on it since I bought it. I had no reason at all to suspect it was faulty. I just consider it one more reason why, when I buy something, I should pay that little bit extra so I only buy it once. Instead of buying the cheap one that'll break in a year and then having to dish out money for the more expensive one anyways.

[@ernstoud]

As Diode Gone Wild would say: daanzjeroooosss!

[@mihaiachim5299]

@ 16:31 In college they told us how advanced the capacitors are now that they arrived with very good parameters at smaller and smaller dimensions :)))) After college when I got to work I found out that all small capacitors have a short life and all the time I buy capacitors I look for them with the largest size of the case ... and the Chinese know that this is what I look for and put in big cases very small capacitors , and sometimes leave the space in the case empty and they are very light, other times fill the case with resin to look like quality products being heavier but you buy the same poor quality product :))))))

[@russellhltn1396]

Tech: "It doesn't work" KZbin: "Recap it!" Tech: "For a heater?" KZbin: "Yes!"

[@Gengh13]

Yeah, the capacitor in capacitive droppers usually degrades and loses capacitance with use (I'm guessing spikes).

[@AlexanderHoet]

Lets make a new drinking game. Every time Dave says "Bob's your uncle" you got to take a shot :).

[@artyzinn7725]

I find that design has a lot of failure points for what its supposed to do; compared to a crude all electrical off on space heaters of the past, they are simple heating elements with electromechanical adjustable thermostats in series with mains and a circuit breaker off on switch. Most parts were easy to source and replace, including all the safety parts like tilt and thermal switches. The US made el cheapos vintage 1980s and earlier can be repaired indefinitely. If it has a blower fan, the motor is a simple, reliable Shaded-pole motor and easy to replace in 2022, the same motor still use for bathroom exhaust fans.

[@180044suomi]

I‘m sure the other space thing named Apollo which was flying to the moon had less electronic parts (transistors) on board than this heater!

[@artyzinn7725]

@@180044suomi yep in design, a space heater is just a big toaster. Even lost heat from an old inefficient but reliable design contributes heat to ambient, which is what you want this thing to do.

[@Shnick]

I had a electric smoker with a wire laying against the hot parts. Worked once, melted the insulation and was obviously done by an 8 year old assembly team.

[@mumbaiverve2307]

Loved watching this video ! Learnt something useful esp. about the caps. I have seen a few capacitive dividers using those brick red caps @19:21. Are they the Y class caps ? What material caps are they ?

[@simon7719]

That's interesting, out of the two household appliances I've repaired, in one I only replaced an X-class cap like that, and the other I think one X-class and one electrolytic. Maybe do a component search vid on those things? They're usually specced way (*way*) lower than high quality electrolytics, like 1000h@85 degrees or such.

[@jayfowler4747]

I repair whitegoods and replace loads of x type caps, in fact any cap dropper type power supply I have problems with the first thing is always the cap, regardless of the brand. Their terrible for failing....

[@liam3284]

Also, seen a few such failures on X class caps. Usually an accelerating degredation.

[@sarathai2876]

That was fun 😊

[@mcs2944]

Standard X2 Polypropylene Film Capacitors designed for across the line applications always degrade and lose capacitance in this way when incorrectly used as a series capacitance in a capacitor dropper power supply. TDK Epcos and Vishay have application notes and have Polyester Film capacitors designed for this purpose instead. The other aspect of self healing capacitors used for X and Y applications is that the self healing mechanism results in reduced capacitance. I had this problem with some products at work. A polyester film capacitor designed for capacitor droppers was the solution and has been reliable in these products ever since.

[@longrunner258]

Severe surge exposure aside, does that excuse the *massive* degradation (like to

[@philippe5394]

Dave, hello from France. When I saw the beginning of the video, I immediately thought of this capacitor. I had to repair 3 identical heaters for my son, all three with the same failure. However, I replaced them with quality capacitors but with double the capacity 680nF instead of 220nF! And since then, I haven't heard of it! It's a shame to see this on the market!

[@ulfg1409]

With bigger caps you feed more current into the following circuit. There's probably a zener taking the excess current as it maintains the correct voltage, if it isn't big enough to handle the extra power you may get a new problem there instead. Bigger caps are good in many places. This one may not be one of them.

[@EEVblog]

In this circuit configuration you want the exact same value otherwise you'll have a higher zener current.

[@markcummings150]

@@ulfg1409 exactly. the bigger the cap, the lower the Xc (AC resistance), meaning more current into your circuit that has to be dissipated somewhere else. ie. the zeners.

[@markcummings150]

Assuming those caps in your heaters are performing a similar 'dropper' function, you should change those caps back to 220nF X2 caps to reduce the excess current into the zeners. if you want to use a higher voltage then that's probably OK.

[@Alexander-qz6px]

You are just intentionally teasing the uCurrent in this video, right? You mentioned in the last(?) live stream that you wanted to make a wrappper video showing the different prototypes. I'm still a fan of the concept. Sure, I guess you could put an RD-Tech power module in a box with a lipo charger and battery for 30 USD total now, but I think it is stil a worthwhile project to show. I'd be interested in the reason for not pursuing it further (if there are different ones then the one I mentioned. Greetings from Germany.

[@bluerizlagirl]

The self-healing property is why you shouldn't use X-rated capacitors as voltage droppers. (There is no safety issue in using an "ordinary" capacitor here, as there is by definition something in series with it to limit the fault current).