Test of the Yihua 502D USB bench power supply. (With fix!) 

I envy your ability to draw an accurate schematic from just looking at a printed circuit board.

I like the retro 50's look of it. The size is actually very practical. The room inside with vents help to minimize components from overheating and the large meter is pleasing. In this day and age of miniaturization to the point of marginal safety and utilty it's nice to see something that would not get lost beneath a postage stamp. A little judicious tweaking makes it perfectly functional. A bit of QC at the sweatshop would have been preferable but otherwisw I'd give it a crooked thumbs up.

It looks like a late 1990s computer speaker case.

I see that flash tester has a "BURN" setting, I'm surprised we haven't seen that in action.

I love your reviews, you continuously consider our mere mortals, and manufacturers, and therefore obviously install trust in your very educational videos - we can see and understand what you do (and what the designers/manufacturers intended)!!! Please keep up the exceptional work!!!

A "classic" from 2018. Very COoL. Thank you.

Seems like a nice case... just awaiting the transplant of a better power supply circuit.

Even though I don't understand anything about electrical work, I find Clive's voice soothing. Plus he takes shit apart and I like that.

Still waiting for the day that little fan kicks on.

Oddly enough, I had the "muh-na-muh-na" Muppet song in my head for weeks. Just got rid of it when YOU set it off again!!....bugger!

I rarely tinker with electronics but I really enjoy watching these videos

CE means Caveat Emptor :)

Well here it is, 2021, the world has changed, the age old question "who was that masked man" has taken on a much different meaning. Following this video, I purchased that power supply, added that resistor and it has been my primary 5 volt power supply when I just have to have over 1.2 amps power. It does a wonderful job, runs all my little single board computer for testing and setup with operating system, it has never given me an ounce of trouble even though I have a set of LED'S hooked up to the screw terminals to light up the shelf where it lives. When ever I need the light, or need the power 5 old LEDs mounted on a strip recovered from an old LED flat screen TV that ended it's life when the damn cats started fighting behind it and actually knocked the blasted thing on the floor shattering the screen. At least the led's are serving some purpose. Cats still run the damn house too, the penalty I have for inviting my daughter to come live with me following the death of my lovely wife of 51 years. She cooks and cleans for me, and insures I don't go off the deep end so I guess the cats are worth it, plus the cats have long since settled down and become my friends and nightly companions sleeping in the bed to keep me a bit warmer in the cold Dakota nights.

You are quite forgiving when it comes to the intentions of the manufacturing. Great video!

Never seen chip markings on your channel this bright

The "Muppet" song came from an Italian soft porn film. www.slate.com/articles/arts/culturebox/2011/11/_mahna_mahna_how_a_ditty_from_a_soft_core_italian_movie_became_the_muppets_catchiest_tune_.html

"I Think I'll Give This The Thumbs Down ..... " - Right, well that's it then, innit. 14:55 "I'm Not Giving Up That Easily .... " - And another bit. I'm glad you were able to rehabilitate this supply. It did seem to be worth the effort.

I love this little PSU. I give it a big thumbs up. I added a Pot to con3 like you did and tweaked it good. I however wasn't surprised by the lower than 5V because on the ebay listing I got it from it said: Output Voltage: 5V -6% (that's 4.7V). Still unsure as to why they did that though. Anyway, I put it under load with 2A and zero resistance and tweaked it to 5V. Now without load it's reading 5.21V. What I'm doing now calls on another BCDC thing...I've installed 3 nokia Lithium batteries and hooked my 12V solar panel to it. Switch between power sources. Love this little box.

This is cool, I am glad we have guys like you on this platform who give so much information. Keep up the good work!

bet the 1A is the rating of the supply fuse :)

"It's tolerable". And it's cute as hell! :-) I love the analog meters. (Yes; I'm Old!) I am glad you were able to tweak it.

Oh, that volt count ONE THOUSAND VOLTS FIFTEEN HUNDRED VOLTS TWO THOUSAND VOLTS I miss PhotonicInduction videos so much. YOU MADE ME REMEMBER IT AGAIN, CLIVE!

Replace the 5v board with the one from your switched power socket.It seemed to be a better design (and you were very impressed with it.

3:48 "But I dont have banana to banana" That actually surprises me :D

Yeah, that's the sort of wire stripper I've always liked because the action seems nicer to me and more controlled than the common labeled entry type.

It's just lovely that the warranty seal on the insulation tester is already broken :D

Too bad you can't double like stuff. Very interesting to watch some of these a few times. Thank you.

Yihua 502D USB bench power supply 5V 2A PSU Clive used 47k ohm I went with a 56k ohm 1% This gives: 5.21V with no load, ripple 4.4mV, 5.12V at 1A, ripple 63mV, 5.05V at 2A, ripple 84mV. I then added 470uF 16V and 100nF ceramic capacitors in parallel on the front panel PCB connecting these extra capacitors across the PCB tracks near the output terminals. This lowered the ripple voltage, now I get: 5.21V with no load, ripple 1.8mV, 5.12V at 1A, ripple 22mV, 5.05V at 2A, ripple 31mV. Mark

Seems like an interesting little device regardless of what you had to do to it.

OHH BANANA!!! Would also be interesting to see how much noise these psus produce versus load using an oscilloscope. Keep up the good stuff! Cheers!

Well I had to watch this one once again.. WHY? Well I tired of the political fight that we in the USA are now engaged, following the bloody Saturday that ended last week with so many dead or wounded. Nice to relax to the sound of Big Clive, and talking about my favorite 5 Volt Power supply. Having used it now on at least a weekly basis, I can testify that she is a great little power box! I love the needle for a quick view of the amp draw, never though about how nice that would be till I have it. I have a set of crock clips plugged into her all the time, they hang from my fan remote that is attached to the side of my old desktop PC desk that now serves as a sort of work shelf next to my old electric recliner where I spend my days trying to count out the hours upon hours that I still have in this wicked world. Over the past couple of months I have built several rather good variable power supplies, some with fixed output banana plugs, others with variable voltage and one nice little unit with both amp and volt variable, yet when it comes to 5 volts, I always reach for this little guy. Could be because it rests right at my elbow while I have to plug in the other, or may be not.

I'm pleased to see you were paying attention during your Latin classes.

The 1A rating on the back appears to be for the fuse after buying one of these for myself. The mains fuse is 1A, you will note the fuse symbol adjacent to "RATED CURRENT 1A" on the label. The fuse is a fast blow 1A. The supply easily delivers 2A output

This is pretty usefull for repairing phones, you can tell if there's a short on the charging circuit or fault in the CPU by seeing the amperage

Clive, I suspect the 3mA on the Opto LED might not be enough to drive the phototransistor into saturation, causing significant dissipation in it. Or maybe the IR from the LED leaking and messing with the FLIR ? try taping a bit of AL-foil to the opto to block IR w/ some black tape on top and FLIR it again to see if it's really that hot?

Never heard caveat emptor realted to CE before, i bursted out in laughter! :D Thanks for that one

Love your videos! I learn alot! It would be interesting if you took these crap products and switched out components to make them work they way they are advertised!!!!!!

I thought CE meant Cheap Electronic!

Do doo, duh doo doo, duh doo doo, duh doo doo doo duh doo........ Bananana...

Lucky for me, Clive, I _like_ that song!

3:40 didn't expect this man to start singing - but there you go

Hi Clive. I used to work in Argos 0475, restocking the shelves. One Christmas I made a CD which had 26 tracks on it, unfortunately it was only the Muppet music. The stockroom manager kept playing it over and over until the Muppets (staff) did something useful. I'm just glad I worked nights, but we still played it for over 6 hours Mon stop.

A friend of mine recently worked in Manama for a time. Yes, Manama. No, my brain wouldn't stop doing it either!

And to avoid using the death-dapter you'd have to replace the lead. It might be nice to replace the insides with a decent phone charger and make a Frankenstein's monster power supply with a neat readout. Depends on the amount of hassle and price of the unit Edit: it's about $20. With that in mind it's suddenly a much tougher sell.

The flir printouts look top notch !

Addictive channel 😊🙏 Thanks Clive!

DAMMIT CLIVE! Now I have that Muppet song stuck in my head!

Interesting the back label says it's rated at 1 amp but then the spec for the usb port is 2 amp. After watching this I'd say the 1 amp label would be the safer option to go by. Thanks for the fix because the unit looks interesting.

Yeah thanx ... for that earworm of a song in my head ... looks like another late night for me :)

I'm tempted to buy this Yeeeeehaw! PSU for digital projects, should be adequate for simple stuff.

That voltage drop isn't bad at all. Fixing the 5v reference would make this thing quite useful :P (5.1v with no load would be ideal, imo)

So much hardware that they actually tried to make it safe!

4:50 it's called "hiccup mode", and is a short-circuit protection mechanism.

Hi Clive! Nice video and that Motorola Charger a have the exactly same for my Motorola Nexus 6 with a european 2 plug on it.

I think that the voltage being set to approx. 4.6V is a symptom of the feedback issue. IE set the voltage to 4.6V and the voltage on the output of the feedback winding will be approx. 10% lower than if the output was set to 5V. V=IR so P=IIR and reducing current by 10% (assuming the feedback in the chip is a resistive input which they usually are) will reduce the power dissipation by 19% approx. Set the output voltage to 5V and things will get really hot.

Well it's cute. I don't think I'd ever employ it but it's a neat little unit.

Yep. Singing Banananam in my head now. Thanks Clive!! :)

the muppet tune gets triggered in my brainbox when i hear the word phenomenon

I got an Aneng AN8008 multimeter a while back as I wanted a cheap second meter, I chose that one as it comes with a big bundle of lead ends including banana to banana, screw terminals etc... They seem to get reasonably good reviews from the likes of EEVBlog considering the price.

The leakage “voltage” is a direct measure of leakage current. It is the leakage voltage divided by 10Mohm input impedance of the multimeter (or whatever it is). In your case it was seemingly 1Mohm so 90V/1Mohm=0.1mA. With a current shunt it came out to 0.2mA. Right ballpark. But be careful with using low impedance circuits for such measurements: they form a transformer winding. It doesn’t take much to induce 0.1mA in a coil of wire that’s close to other transformers etc.

I got one of these unit awhile back, and found that the output seems to be live at half the mains voltage. (Thailand uses 220V@50Hz) So I just took out the power supply board and replace it with DC buck regulator, so I can power it off an "known good" DC supply. Since then, its very useful for testing cables and 5V powered devices

It seems to me that the 1A rating on the back refers to the primary side fuse.

Probably a nice solid 5.1v before the output diode. Replace it with a Schottkey, and it would be fine.

Clive, Caveat Emptor won the day XD! Brilliant and... unfortunately so true..

Thanks Clive :) I find your hacks, & repairs more interesting than your more common power supply circuit traces and look forward to more content like this. Have you ever tried keyboard bending?

"Mode select: breakdown, trip, BURN" You know what to do! And make it 4kV.

I'd say a worthwhile endeavour would be probing various bits & bobs on these circuits with a good old fashioned oscilloscope. The switching on that optoisolator for example ought to show up rather nicely. That and output ripple, though I don't know how much modern day electronics care about input power ripple - you're in a better position to make that judgement. Also it would allow for some interesting comparisons between "proper" OEM power adaptors and the poundland specials (especially the good ones!)... I mean they *say* it's DC, but... That said, there's only so much the scope can pick up, so some sneaky really high frequency switching noise might make it through undetected :/

15:01 "I connected a couple of connections to this connector" impressive

@Clive - With the panel meter going to 2 A full scale, I would have interpreted "rated current: 1 A" as the *maximum inrush* current _at 220 volts._ I was surprised you did not measure Power Factor, which might have some bearing on maximum inrush current from Mains.

Woot, long live Beaker! but I still love the Swedish chef.

3:46 When was the first time hearing that melody? Late summer 1967±? on The Red Skelton Show during a _Moon Man skit._

I have had many cars in the shop with the digital displays having a wave or pulse. Go check the alternator and it’s putting out some AC voltage. The bridge rectifier is going bad and time for a replacement alternator. Usually it’s been to other places and they couldn’t figure out what was wrong. So anytime I see a display do that I see if it’s putting out AC.

I've had lots of issues with the floating AC aspect of USB power units. I have some power strips with USB and there's always that 90 volts AC to ground at a few microamps. I found when I was charging my phone the touchscreen was erratic. Not surprised really. So I have reversed engineered them all. Dismantled and soldered a wire from the USB socket housing to the mains earth bar of the power strip and had no more problems since.

oh bugger off clive! I'm gonna have that stuck in my head for a while now!

Could you teardown a lightning splitter for the newer iPhones? I’d love to know how they work

Love your videos!! Very informative. Thank you!

I want to hear some "hysterical SCREAMING" lol Love ur video's ! Keep em coming !

Hhmmm! Fused neutral on a cable with a two pin plug that can be inserted either way round. Better than no fuse at all I suppose.

Between the dedicated chip from Power Integrations on one hand, and the opto-feedback on the other hand, that looks indeed like a half-decent little unit. As opposed to, say, some bottom-of-the-barrel two-transistor oscillator with aux-winding feedback... Maybe with an electrolytic "critical cap", which upon failure, makes the secondary voltage go sky-high...

Damn Clive I do have the song stuck in my head

That's a very stylish power supply. It'd be neat if you could make an adjustable supply out of it for light duty stuff.

I wonder if the delux model had a pot to adjust the O/P voltage

This dude is quite neat.

Bana nana!! Thanks Clive.

Maybe the on-load drop is the panel meter. Some cheap current meters have quite high series resistance.

Looks like the optocoupler is not turned on/off fast enough, because zener diode's characteristic curves are not really "rectangular". So the transistor spends too much time being "half on" and thats when it gets hot.

Well making it a lab power supply would be nice project, adding potentiometer, (maybe some sort of current source).

i have a soldering station that comes with a power supply included. 15v 1A. love the soldering station but never used the power supply, mostly cause im starting out and lack creativity to make anything

Handy little case ditch the guts and PCB replace it with a nice little BangGood module.

The power supply module inside is a pretty standard part and it is double insulated

the 1A-2A question: if you order a 2A version, you get the same electronics with different sticker for twice the price :)

Clive you sod I've got it stuck in my head I've been whistling it all day 😂😂🤬🤬

should be able to remove one resistor on the TL431 and add a pot to tweak that voltage without much trouble and if the correct other value resistor was OK could make a variable supply

Thanks for that song Clive. Yup, going to have that in my head now! I would like to see some more power supply reviews and 'flash over' testing on the cheaper supplies. Have not seen a supply fail this test yet from you or have I missed a video? I love power supplies, only because like you, I hate surface mount components! Generally big chunky power supplies have both but probably 75% through hole components so can be 'easier' to troubleshoot and even mod to your liking. I have server power supplies which are built like brick s**t houses so may review one soon!

Tip: Those flimsy 2.5A Europlugs might be supposed to be able to be rammed into a UK socket if you defeat the shutters. This may make a more secure connection due to UK pins being thinner than German 4.8mm pins, which is still thinner than an angled Australian pin also accepted by the deathdapter.

That power supply use in phone repair when you need to turn on smartphone without battery an want to know the how current being pulled from device 😊👍and that 4.2 voltage means a fully charged phone ( lithium ion ) battery

If they are using the opto-isolator in analogue mode, then it is not surprising that it gets warm. When used digitally, the transistor will be either totally non-conductive (zero current through it) or totally conductive (zero voltage across it.) Either way, there will be no power dissipated within the transistor (maybe just a little bit, as it probably has a fraction of an ohm resistance in real life). But when the transistor is only partly conducting, there will be a voltage across it and a current through it, therefore non-zero power dissipation. So it will get warm. Perhaps you could attach a heat sink to it? You would need to put a mica insulator on top of the opto-isolator and extending over the pins, in order not to spoil the isolation gap.

"let's open it up" never heared clive say that before

There are some similarities between that circuit board and the USB power circuit from the British General USB wall socket in the previous video. The other one is smaller but I would think it would be a better option if it could be mounted inside the box.

Analogue displays, I prefer them for some bizarre reason. Maybe I’m just old school lol