In the early days they were outright scary.

Actually, this exact thing took place over a hundred years ago when Henry Ford put the ignition coils in the earliest cars. Then along came Kettering with the coil, 'condenser' and points to repeat the same thing. Now we have chips that do it in microseconds. 👍👍

@@acmefixer1 That's true. And the "flyback" circuits in CRT TV's and video monitors work similarly. Still, it's kind of amazing that these circuits are so reliable if built correctly. On paper, it seems like they'd be doomed to a fiery death in the first second of operation.

You forgot the HF chopper. In the 80's I fixed dozens of SMPS' in commercial equipment (third party IBM network muxes). They used all discrete components back then. It was always the output electrolytics that bore the brunt. They ran HOT. Times sure have changed.

@@ScottGrammer That's because you're thinking of this like it's a DC circuit. It isn't. You're not thinking about the inductance involved. When the mosfet first turns on, there's not a dead short across the supply. The coil is nearly open at that point due to its inductance. It gradually starts conducting more and more current until the mosfet turns off, sometime before it becomes a dead short across the supply.

Still a diode !

seriously it was kinda getting monotonous here with all that LEDs

Diode was obviously defective, no light output!

@@greeceuranusputin Gold star !

@@greeceuranusputin any diode can be a light emitting diode if you stuff enough power through it.

I like them as well, this also is a very good way of teaching people, especially as Clive gives them a little fun in the mix too.

Anything to do with mains I always use a 3a fuse in the plug

@@joshuabest100 In a test like this it is much better to replace your fuse with say a 40w or 60w incandescent light bulb, if it comes on the device is still shorted, but will not explode because there is not enough power available for blowing stuff up. For a KZfaq channel though it is better without it: because you will have sparks and flying shrapnel which is always cool! :D

@@perhansson6718 that's a pretty good idea tbh I might use this

@@perhansson6718 that explains why my TV repairman grampa always used a light bulb for various kinds of testing

@@perhansson6718 haha indeed😂😂😂😂

The best keyboard I ever had was a Mitsumi. Cost £3, only bought it to pad an order out for free p&p. Nice and clicky despite not being a proper key switch. Reliable, light, nice typing angle.

Yep, good old Japanese brand name. Nice spacious design here, and repairable.

@@Zadster I think i used one of those for 10 years, until repairs kept piling on and it no longer felt great. But nowadays, i'm exceptionally happy with a generic Chinese mechanical that i found used years ago, this is the best i've had so far. But they're also the manufacturing company behind Nintendo's products, also contributing some of their engineering. Gamecube, Wii era stuff was so good! Then again the word is they're also the ones manufacturing Nintendo Switch, which retains its glaring controller drift issue, though ultimately it's an engineering issue and not materials or assembly quality issue, and ultimately Nintendo isn't doing anything about it, so that's pretty telling.

Indeed. Mitsumi is an old established brand. I would assume the product is good. Which is much different than the usual random maker.

i got them confused with Matsushita

More componet sparse so it's easier to follow along maybe?

Yeah me to, Diode Gone Wild does a lot of 'em.

You're drawn to power electronics, it's Just how it is

@@masteryoda394 A powerful draw, it is

@@andymouse Freaking love that guy of couuuuuurse. And here is my cat, of couuuuurrrse...

That's why the Alibaba $19 gaming computer power supplies are the best. One or two of them can corrupt an entire MRI machine in the same building with their electrical interference.

I'd still buy one for a dollar.

@6GDC You don't mean computer PSU surely? It bears reading the specs carefully, if it's a programmable power supply, they will have voltage dependent maximum current. 40A at 3V output maybe? Still a massive massive accomplishment, IF they did it, but it can be done, but it will be rare to see anything with more than 10A outputs. I don't know the product you're speaking of, but by far not all impressively specced and aggressively priced Ali products are scam junk. Ali computer PSUs that the dollar guy speaks of, are just salvage junk or copies of old ATX1.3 computer PSUs, with maybe a power handling of 200W or so that rough order of magnitude, just made to look like modern PSUs on the outside.

@6GDC How feasible a pocket-size 40A switch-mode power supply is depends on a few things, such as: how large "pocket size" is; the input & output voltages/voltage ranges; whether they bothered with EMC (needing space for filtering components); etc. Modern MOSFETs have extremely low on-state resistances (the "R_DS(ON)" value¹, i.e. the resistance, in Ω, between the Drain and Source pins at a specified Gate voltage). Even very cheap MOSFETs can have R_DS(ON) ratings well below 10 mΩ, and this results in very high current ratings, especially for the size. Lower resistance means a lower voltage drop, less resistive heating, and thus more current before things get out of hand (I'm kinda guessing here, but it makes sense). Clive's shown a couple of devices on this channel containing SOT-23 MOSFETs capable of several amps of continuous current - and SOT-23 devices are only 2.9×1.3 mm (top surface; Wikipedia doesn't list the height of SOT-23). The "USB power bank that [intentionally] gets very hot" video comes to mind. It used one of those SOT-23 MOSFETs to switch its heaters, IIRC. There's also the recent emergence and popularity of gallium nitride MOSFETs, which claim higher voltage ratings, higher efficiency, smaller overall device size, and other benefits. They've driven the recent influx of "GaN" SMPSs in the consumer space - e.g. USB power supplies and phone chargers, especially high-power USB-PD supplies. Those devices can supposedly be made smaller and lighter with GaN MOSFETs, as well as being more energy efficient, in theory. (No doubt some of those devices are just slapping "GaN" on the packaging/product description as a marketing lie, but some are probably genuine!) Further reading: en.wikipedia.org/wiki/Gallium_nitride#Transistors_and_Power_ICs (and the rest of the article for more general info about GaN tech) So your "40A" SMPS _could_ be genuine! It's not totally unrealistic, IMO. ...but it could also very well be a wild exaggeration! 😁 ¹ R_DS(ON) is typically written as "R" followed by "DS(ON)" in subscript (no "_"), but I can't use subscript on KZfaq - at least not without obscure Unicode characters that I don't have easy access to on my phone - so I'm using "_" to indicate subscript.

@6GDC NOT 40A at 170V, almost 7kVA, you can be sure. Read between the lines - maybe 40A at the lower end and use that calculated wattage to work out what you will get at the higher end. That's how Shenzhen do. (mebee one or two amps if you are lucky?) Still respectable but not 7kVA.

Ha ha ha 😂 ❤️ the flux is the spirit of the electrons

Much rather too much Flux then not enough.. I'm the same way when doing electronics specially pcbs cause I'm always worrying that I may burn up the paths

Yeahhh..more flux with leadbased solder😁😁😁😁

XD😊

@@johngarritzcx6733 always hate non lead based solder always have to use 80-100 watt stations. Can't use my 40 watt gun or my 60 watt station.

This is not ElectroBOOM, you know! ;)

It's good for cardiac arrest stimulation.. probably not a great idea Ryan lol

@@NaterNorris charge the capacitor to 450v then tell your buddy to catch

A zap to the fingers will have you hopping ...done that many a time..

I have a bass amp that has dual secondaries +-15 and +-45 the 15v neg rail failed and was doing what you describe but after replacing caps there was some huge charge then a bang across the -15v rail the windings are now open on the secondary, smps are great but if you lose the transformer it's game over

I re-capped my DBX 286A microphone processor with all new Nichicon caps. It wasn't a cheap prospect. I don't regret it. I got it faulty from Ebay for $49. It's fully functional now and quite impressive. The only two I did NOT replace were 2 bi-polar caps that I had not prepared for.

@@TechGorilla1987 The Nichicon Muse ES series are the ones you want for the bipolar caps. Lovely shiny green sleeves!

Even just AM radio is basically unusable in my apartment block because at least one household uses these shitty PowerLAN/DLAN ethernet-over-powerlines adapters, turning all the electrical wiring into a giant antenna transmitting a f*ckton of noise/interference (think cheap chinese switchmode PSU with barely any filtering, but on steroids)

@@Knaeckebrotsaege I'm using these every now and then for easy LAN connection across my apartment. Say, someone would like to catch the noise with their SW defined radio, at which frequency range would they have to look? I'm too lazy to do my own research. :-/ Asking for a friend.

@@froedlmetallmann4643 Well the AM broadcast band is from 550kHz to 1720kHz.

Taking a look around, the frequency range seems to be quite broad, being between 2MHz, and around 70MHz.

and... that's why he was the manager

Not sure if that went as intended... :-)

Small dab’ll do ya, big glob,ll screw ya.

"If you’re not Fluxing, you’re not Soldering" - Justin, The Art Of Repair. 👌

The PM, Home Secretary, Foreign Secretary & Health Secretary 🤷🏻‍♂️

Probably someone that has 4 accounts that doesn't know anything about electronics and has a KZfaq channel.

Now 14. That's probably a pretty good average from 2.7k likes. About 0.5% hit the wrong button. I swear at least 3% of the population can't find their own arse with both hands and a search light, so this is way ahead of the curve.

The only moron is the person that thinks everyone has to like what they like on the internet. I liked it but I understand others may not and let them.

It's 38 dislikes now....however its not good to call someone a moron just because they have a valid opinion in opposition to the majority. Its also quite possible to accidentally swipe the dislike on a mobile device.... unfortunately Clive even went down the route of calling people stupid when he decided to way in on the 5g debate a while back.....this was very frustrating because he was talking bolllocks and didn't understand the modus operandi of the effects of high frequency radiation on cell generation and replication....

That's ac input 3phase?

A few decades ago, I was working on (diagnosing) a single-triode power ultrasonic oscillator at the base of an ultrasonic cleaning machine. Went to measure the anode volts, should've been between 5 and 10kV. They were, and my high-voltage probe failed, and punched a hole through my thumb. Very thin hole, but a hole, nonetheless!

That's quite scary if it was you that made the pop.

@@brancheternal Well, not directly, I guess. I’m about as good at wording things as I am at PSU repair…

lol we all have pop accidents. don't just give up yet. PSUs are very easy to fix once you understand its basic fundamentals. safety precautions comes automatically once you nail down its working principle. you'll be surprised how many electronics fail because of single faulty component on PSU and how it can easily be repaired, saving you tons of $$. be patient and learn your basics. dont give up yet

Are you sure the pop came from the board and not from inside your pants? 😂

that's the way a lot of us started out, then learned wisdom

Yes! So often I find the psu pulsing or not starting up because of that little chip/switcher start cap has dropped from say 10u to 4 or 5u. The worse the power quality or noisier the environment (industrial) the shorter the life span of the caps seems to be.

my router broke over a year ago and i still didn't fix it. best tip: document what you do with pen an paper. this is my mulitmeter's 2nd battery.....

@@plageran you only need 2 things for a easy fix , a trash can and Amazon

@@plageran For the battery, smoke detector batteries. Energizer lithium for the win. They're not the cheapest (tho they've come down a bit) but worth every penny.

@Hill lmao and @Mad that's abit of a mod if you're referring to Poundland batteries😂😂

@@plageran Haha We don't have Poundland here but I'm gonna go out on a limb and say it's similar to "Dollar tree" here... If I'm right, you'd be absolutely correct! 🤣

It's one of the best ways to enjoy them.

I have similar stories of that period, in the testing department of a PABX manufacturer and students at the electronics lab of a local school kept doing that all the time, leaving charged capacitors over the benches, waiting for a "sucker".

Also funny where the arrangement of heatsinks and power diodes is such, that the caps get baked real good, entirely avoidably so.

Even when you have a meter it's a smart move to build a little discharge device with a suitable resistor and some insulated wires so you can discharge any caps safely before working on equipment. The meter could be broken and show zero volts when there is still 300 left in the cap you know. Just jamming a screw driver or whatever metal between the cap's legs will discharge it but that causes all kinds of damage.

I always go for the tripple: discharge with a resistor, measure AND jam a screw driver between the pins for final safety check.

Actually, sensitive analog circuits or other high-impedance circuits can behave differently if flux still remains after power on. Cleaning the board can be a good preventitive measure: Or, a corrective measure if you're testing it after resoldering/replacing something and it's not 100% working AND there is visible flux residue.

Could the lack of heatsinking be to blame?

The capacitor bite hurts a lot though, it can be quite furocious._

@@martinlelle6863 from painful experience I can say that DC kicks harder than AC volt for volt, 240V AC is annoying and a reminder that you are probably being stupid! but DC, especially when there is a nice fat cap backing it up will make you reconsider your life choices!