Fixing a faulty USB power supply.
ฝัง
- เผยแพร่เมื่อ 20 ก.พ. 2018
- A friend got this power supply from gearbest and it arrived faulty. He had no luck with their returns system or email, so asked if I wanted it to make a video about. So let's see if we can fix it.
I'm not sure how the back of the case is supposed to be attached, it came off quite easily and that may hint at a rough shipping experience.
Note that the LCD display just says 5V whatever the output voltage is, and it's just the current that changes.
If you want a set of the desoldering tubes then here's a general ebay com search link:-
www.ebay.com/sch/i.html?_from...
Note that the rectifier on the secondary side appears to be an active rectifier type circuit that uses a dedicated chip and MOSFET to achieve rectification with very low voltage drop and heat.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm
This also keeps the channel independent of TH-cam's advertising algorithms allowing it to be a bit more dangerous and naughty. - วิทยาศาสตร์และเทคโนโลยี
I have to confess I was completely lost, not a scoobie-do what you were on about but I just couldn't stop watching. It was so interesting. I have never seen such knowledge and experience in use like you just did. I would have binned it, hence our throw away society we now live in. There needs to be more guys like you Clive, you're a friggin genius, I envy your knowledge and I tip my cap. Well done mate 😉
It looks so badly made safety wise that throwing it away would be the right thing to do, even if it worked.
I always love a product which is held together by luck whilst offering no current limiting at all.
What's the motto in design again? Ah yes "hope is not a strategy". Yet it sure sells.
LMAO
This guy is the Bob Ross of electronics!
"It wins points for accessibility to all the live connections." :)
Yes, yes it does.
The USB supply called 'New Text Document (3)' is better.
Actually, I prefer New Text Document (4). It has more ports and faster charging.
@@andymadden8183 I prefer New Project eventually New folder
Those bastards are more complex and have more functions.
I like my "Copy of New Project 2 (copy)-final-finalforrealthistime" power supply better. *Most* of the old quirks and issues are fixed in that one.
“Product Schematic” might have been at the top of a page giving the schematic, and somebody mistook it for the name of the product and reproduced many times as a label stuck on every case...
I am absolutely sure that's what happened. OR they sent a template for the schematic to the screenprinters and just didn't put the actual name. I have one of these myself. Works fine for me.
The China man didn't understand English much like all those who have Asian characters tattooed and have no idea what it really means.
Like the girl who copied characters for a tattoo from a Chinese menu and it said 'tasty dish'!
Ashley Booth
Could have been much worse, it could have meant fish lips!
Richard Kaz Maybe he did and this is just malicious compliance?
Thanks Clive - I was surprised how complicated the thing was. No need to return it - thanks for the tips for fixing these things in the future.
"They work ok"
That's a glowing recommendation if I've ever heard one
"The case doesn't look super--" *CLANK* "..."
That's not very good
It helps to know how a circuit works and what you are looking for, you diagnosed the issue perfectly and methodically. I've seen guys start at the back end of a circuit and never found the issue. Always start from the input to the output, you have better luck if you don't have a schematic, if you understand what the components do, how they work and what the expected outcome is. Doodling out a drawing of the circuit is always helpful.
20:04 "What holds this in?" That little sticker, that you threw out in the beginning!
"What's holding that in?" pause.... "Luck, I think." 😅
"There doesn't seem to be any current limiting in these USB sockets, which can be useful for some projects." 😂
What's holding it in is the warranty label :D
"It seemed to fly by clean living and good thoughts" - R Heinlein in Have Spacesuit, Will Travel. :)
That was a good fix with a very good explanation of how it powers up and keep itself going.
It had good value to anyone wanting to know more about electronics. Far more value than drawing out a schematic of something that is working, This was something that was not working and you found the fault. This video has more value than a lot of the others where you tate down something that is working, Excellent video , love it. Thank's once again for an entertaining video Clive.
What was holding the cover on ?
The sticker you removed :D
Must have been a load bearing sticker
The QC sticker.
The irony...
ChuckD59
...well.. the quality was according to spec ? and checked ? soooo .. QC passed.
Sheer force of will, that's what was holding it together xD
Sparky Projects, I said that same thing to the screen when he wondered what's supposed to hold it on.
Nice "percussive repair" at 19:45 glad you also use this from time to time 😇
Smashing repair clive :-D
The name looks like someone that didnt know english just copied it from the circuit sheet, thinking it was the model name.
Yeah, I feel that was the case.
Your friend could put his power supply for sale on eBay and advertise it as: Unique item fixed by Big Clive
was holding my breath for the hand test....
No way, he now has a working power supply that is working and has been shown to not be a death trap. Why would you want to take a chance with another one from the web?
+John Bicycle --> No way...put it on a shelf surrounded by slow color changing LEDs or warm white LEDs with a picture of BigClive on the wall above it. LOL
Yeah.... That may or may not be a selling point. lol Master Clive likes things that go "BANG!" way too much. (don't we all)
He should autograph it too, i'd buy it xD
Never seen those desoldering tubes before. I'll have to get a set. Thanks for pointing them out, even though not needed for this project.
They seem to be a common cheap eBay item if you can find them.
Ordered. BTW the key search words are "desoldering needles"
I added a search link to the description.
www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=hollow+desoldering+needles&_sop=15
They are a bloody genius idea!
Purchased. Thanks guys
Nice video. You're a great instructor. I would have put a small dollop of silicone over that "key hole surgery" coming up off the board
Lol I literally just asked you about the dc though a transformer on another video 😁. As always I appreciate the response you gave me.
I love your content it's very educational even if I have to pause to Google something 😆. Always had a passing interest in electronics but you actually hold my attention and make sense. Keep up the good work 💪brother.
Got to give it to the marketing team that came up with the memorable product name "PRODUCT SCHEMATIC".
No doubt they have a version without a display and it has a little drawing to take up the space ;-)
It won't have the output ports either, and the PCB will be unpopulated
A surprisingly decent circuit didn't expect that from Chinese mail order. Those sell for 18usd on Ali Express.
Hi Clive
I cannot comment on commercial equipment but for medical equipment the test voltage as per IEC60601-1 would be 1.5kV for one means of operator protection for class 1 equipment and 3.0kV for two means of operator protection for a class 2 equipment (which is what you have there). The difference between class 1 and class 2. Class 1 has a protective earth (normally connected to a metal chassis) which is 1 means of protection, therefore you only require 1 means of protection from the mains part to the output. In the case of a class 2 devices that does not have a protective earth there is a requirement to have 2 means of protection. According to the standard a grounded chassis is considered as 1 means of operator protection.
A very good explanation on how the circuit functions.
Clive, you should have tested port 6 as that's a different colour which often denotes that it's a special, high-current port.
Patented hand test: *pat pat pat*
Innovative haptic feedback!
+StonedGamers --> Damn...and I always thought the "pat test" was having someone named Pat come over and say, "Yup, looks good to me." It's good I know now because it isn't always easy finding someone named Pat that is willing to come over. LOL
Used to work as a PAT tester at HSS hire, we quite literally looked at the item for damage, then stuck it in the high voltage tester and prodded it a couple of times before saying "yep that's safe" before putting it back out for hire. '
we all do it...
11:30 "The higher the frequency, the smaller the transformer you can get off with." And this is why on airliners the electricity supply is always AC at a much higher frequency than mains on the ground, so that small (and therefore light) transformers can be used.
The main reason is the smaller generator.
It's 3 phase 115V/400Hz on an airplane.
The seat and inflight entertainment is running on DC voltage made from the 400Hz rail.
That is that constant high pitch noise in the plane.
I always thought that constant high pitched noise was someone's baby crying - at least it was for a 14 hour flight to Singapore that I was on!
I would cry too if there was a constant high-pitch noise on a plane
Thank you for you many hour of entertainment and knowledge you've shared with us. When checking capacitors here we go from the screwdriver straight to the tongue, skipping the hand, way more accurate and exciting!! Cheers, Billy in B.C., Canada
Dont worry about flipping it back n forth clive. we have amazing tech called a pause button to look aslong as we like. you do a fine job mate keep up the good work
Actually laughed out loud when the back just popped off with the threat of the spudger... :)
Clive have you ever considered doing some tutorial videos on what some of these common circuits / devices are that you mention a lot on your videos? Like "snubber network" "switched mode power supply" "bridge rectifier" "smoothing capacitor" "filter capacitor", etc etc.
I get a vague notion from context, but I just found myself preparing to search for youtube vids on the ins and outs of snubber networks and what they're for, and I figured it was a shame there wasn't a video explaining it in your dulcet tones.
James Pilcher Nah, we just want to see BigClive tearing tat apart!
haha that is the primary concern i'm sure
Mehdi does a good episode on bridge rectifiers
James Pilcher A regular non-video search should give much better results. You'll find tutorials, overviews, forums where designers discuss how to make the best ones, plus lots of ready made circuits that are not perfect fits for a real world mass produced device like this.
If he went through basic electronics every time we'd all get bored quickly. As said, get a book or google the items you don't understand.
Holy cow, those stainless steel desolding tubes look neat...Im buying them if I can find em...desoldering double sided boards is the bane of my existence
Fine bit of soldering there, it's not easy squeezing your tip into such a small gap, even if it's just for a minute... :P
That's because he didn't - the wire was heated from the other side of the board.
23:02 - ...and then after that, let's stick a load in it
Someone been watching AvE...
Jonny T RELEASE THE SHMOOOOOO!
Jonny T obviously... Just the tip and only for a minute
WOW... Great work Clive. Always nice to hear your soothing voice !!
I think a while back I came by some local regulations in Finland before EU. Insulation requirement was 4kVac for 1min. I've had the impression that EU regulations were similar in insulation requirements when CE compliance came.
Funnily at that time insulation transformers (used in equipment repair) needed something like 8 or 10kVac (1min) if my memory serves well. I guess there was need for some margin in case the device under repair had any high voltage sections on itself. (I tested my isolation transformers at 12kV because I had suitable source for that voltage.) Touching insulated equipment with that kind of specs is pretty safe, safer than touching commercial appliance.
Nice to see you repair something. It is always nice to see things taken to bits but also great to see it work! GOD JOB.
'Product Schematic' is the new name for ACME. They went bust due to litigation from a coyote.
When they are repairing stuff on youtube - loose wire or something simple stupid like that
When I'm repairing something - dead FPGA for 100 pounds
>.
The videos of those are just never uploaded, since they're both a waste of time for the audience and anticlimactic.
Man I know that feeling Arek. Or it starts with a similar fault, but it ends up it's actually dead windings, a blown mosfet, a somehow-deprogrammed chip. Things that are just. Unfixable unless you control the mighty forces of nanometer sized components.
I actually once got a CP2102 chip that had the wrong firmware on it (registered as some OEM device on USB, rather than the generic USB-to-serial stuff). I ended up being able to fix it by copying the firmware from another CP2102 USB-to-UART adapter to this chip.
I’ve had an on-board power supply go into berserker mode on a board with a $5k FPGA that I really needed to finish a project. Not a happy day for sure. Eventually I figured out that some capacitors had marginal ESR by design, and as they slightly aged, the supply started pushing a sine wave on top of the about 1V the FPGA’s core needed. I couldn’t really blame the caps - they did their job fine, not their fault that the design was wonky.
Or even better, your friend could put his power supply for sale on eBay and advertise it as: Unique item -- fixed by Big Clive -- while on aspirin ...
Or even better, you can post your comment twice to get twice the likes
Unique, unlike your comment.
and the "hand test" brilliant!
I've got one of those that I have to open as well in order to replace the light led for the LCD display...........great video.
I have one of these. I love it. Had a ball of solder rolling around in it When I got it and the solder joints on the input were cold. After addressing those problems I love it
I have found when using an isolation tester sometimes if you go to high you will take out a part without realizing it. In my case someone changed the machine from 40VDC to 500vac without letting anyone know and it ruined all the output filter caps that were rated for a max of 50V. We didn't realize they were bad until we got a complaint from the customer that the units were acting different than usual.
clive this was a fantastic video, very well put together. i started in electronics in 96 as a tv audio sat engineer. 10/10
I find these videos very relaxing, thanks Clive.
I hope you don't have the flu. I got it the last week of December. I thought I had a cold too the first day, the next evening I was found passed out on the floor from extreme dehydration and back pain related to chronic injuries. I got sent to the ER. The flu is quite serious this year.
Get well soon,
-Jake ;)
I’ll feel blessed if the cold I’m getting over from is the only communicable illness that I get this season. Feel better sion sir! Love your videos and want to see more!!!
Superb theory and repair,keep it up young man!
The USB ports are upside down. I don't like that.
You're gonna have to flip them 3 times before they fit in any case.
Me neither. Who designs things like this.
Jeez! We all know when plugging in a regular standard sized USB, that the "seam" is "face-down" so to speak.
Oh, I get it. China, like Australia, being on the other side of the equator...
Yeah! EVERYTHING'S upside down there, innit?
Makes perfect sense.
My faith in my own imbecility is RESTORED!
the equator is actually slightly south of the southern tip of India
Luke Den Hartog the electrons are going to fall out
the equator that goes from top to bottom is what he meant :P!
Those desoldering tubes looks very handy!
I died when you managed to just pull it off effortlessly
I highly doubt that you actually died.
You doubted correctly.
I LOL'd. It looks like that QC sticker was about the only thing holding that cover on. It even floored Clive... And he's seen _lots_ of ''stupid manufacturing tricks''!
Terrum
But did you dieded?
That's what she said..
I was about to buy one of these off Aliexpress. They are much cheaper on Aliexpress than Gearbest, which itself has wildly varying prices.
Spec says: Single-port USB output maximum 3.5A, 6 USB ports total maximum output 6A. I'm a bit wary of these cheapo chargers as my current one actually managed to blow out one of the USB ports when a crappy iPhone cable shorted whilst plugged in.
These are the best electronic videos I had seen yet on the internet thank you I love doing electronic projects.
Thank you much for the explanation of the boot strap circuit & the feedback winding, now I can understand that a lot better, thanks Clive.
LOVE that meter! You can read it from the other side of the room.
Brilliant bit of work!!! Feel better soon.
Big Clive, love the channel! Seems like every video you were discharging capacitors. Would love to see what would really happen if a analog touched a live capacitor that was roughly fully charged. And the Damage that it caused! Thanks for all you do. Wish I can make it as big as you have maybe one day. Please have a great day!
Wish you taught my electronics class! Loving your videos!
From the EN60950-1 Standard "Information technology equipment. Safety. General requirements"
Table G1 Says for an AC supply between 150 and 300VACRMS in Overvoltage Category II the mains transient voltage is 2.5kV
Section G4.1.b.b1 Specifies the required withstand voltage is equal to the mains transient voltage at 2.5kV
Table 5C Then specifies the required test voltage for reinforced insulation with a mains transient voltage of 2.5kV is 5kV (peak or DC)
Section 5.2.2 Then says that for certification testing you would ramp to the required test voltage from 0V and then hold it for 60 seconds. It then goes on to state that for Routine Tests (ie production time test) you can reduce the 60 seconds to 1 second and reduce the voltage by 10%.
Therefore for routine testing you can use 4.5kVDC and hold it for 1 second.
What is the purpose of this test? I'm a refrigeration tech in USA. We test our motors for ground faults with Meggers 500-2k volts. Is this the same? A standing merger test we call a hi-pot test & can be up to 5kv for large motors.
Given that all USB ports share one 5 V supply I wonder if all USB ports together can actually deliver more than 2.1 amps. Since there seems to be no real current limiting, unless the single USB port connection provided enough resistance for the voltage to drop like that I would assume all ports together not to be able to deliver a lot more than a single one...
According to IEC 60601-1 the dielectric strength test for a mains part to give 1MOOP (one means of operator protection) is 1500V.
Don't know if it was just me but the V test affected the camera lol great videos Clive you got me back into electronics :)
Fault analysis on the fly. Magic!
"I could regret this." 😂 Sounds like me, at various points during such an activity.
Nice job Clive, thank you for posting.
Genius repair! Thanks for sharing!!
At 18:50 - Those needles have helped me many a time when the via just wouldn't open!
Actually, there is only a very little amount of parts really mounted to that heat-sink, so it should be easy to remove. But unfortunately, as there are only a few parts mounted, keeping the heat sink in place, it seems to be glued at several places, so it doesn't rip parts off when being thrown and dropped. So what I do in such situations is, to un-solder all components fixed and glued to the heat-sink and remove it in one large piece. By that you can easily reach inside and fix whatever needs to be fixed.
The desoldering tool he's talking about at 18:30 is called "hollow needles" on eBay. They're almost free.
Aye thanks, gonna buy me some. They seem useful as frig. So many times I wished to just punt something through the holes.
Maybe I can mod them to be part of my soldering iron somehow.
Totally agree with the negative comments about Gearbest. Terrible customer service. I bought a flash unit missing a diffuser. After about a month batting emails back and forward, I got PayPal to refund me. They suddenly became very helpful, but lesson learned.
Thanks Clive, much easier to understand notepad format.
Would love to see a video on a homemade capacitive battery charger. I searched channel, but didn't see that you've done one. I'm making one this week and it would be great to hear you explain what NO ONE should build one and how it will kill me. :)
Damnit... another gadget I can't live without!! and a $1.45 freepost as well!!! hahaha cheers Clive could have done with these a couple of months ago repairing a Swtched mode supply double sided!! What a job!!
I got a 5 usb port "tower" charger from poundland and it worked until the first time I unplugged the AC cable from it. Then it would make a crackly noise and not power anything. Turned out the AC power jack was only held in place by 2 very loose plastic plugs and the solder connecting it to the PCB which had pulled off. I sorted it by melting the plastic plugs with a soldering iron to secure the jack in place, resoldering the joints and hot gluing the hell out of it. Works great now, but it might be a common problem with that particular model.
I hope you feel better soon!
Strangely fascinating video..thanks for posting. I can't analyze a full circuit component by component, but I do always pull something apart, if its low voltage, to try to fix it. I get circuit corrosion a lot. I live near the sea and the salt in the air has an effect on electronics, well thats my theory. Cheers Stephen
With the tip, bootstrap circuit, i can now repair my electronic ballast. Thanks BigClive !
I learnt something new: I'd never seen de-soldering screwdrivers before.
17:20 No, the term you're looking for is " *keyhole* surgery " :P
17:43 Confirmed :D
Great video! It's one of those times where I wish I could support your channel more. (very much living off noodles!)
How the hell do you afford noodles?!?!
I cleaned the tea out of a used tea bag and filled it with the "flavor packet" so I could use it more than once. I had to sell the noodles to afford water...
Hey Clive! I love your videos! If you ever want any usa exclusive products just give me a shout and I’ll make sure to mail it to you! Thanks again for making these videos, it’s really cool to be able to watch these videos and learn from your experience with these items without the items myself. Thanks again :)
Feel Better Soon, Clive!
You set off my Amazon Alexa twice in this video. Once at 15:49 and once at 26:50 and it even started playing BBC radio 2 lol
Me too. Seems to me his pronunciation of "Lets, ah..." as he is thinking about what to do. :-)
I'm glad you mentioned the cold at the start, it gave me chance to put my mask on to watch this.
"lets discharge this cap by poking it with a metal handled screwdriver"
Well done mate.
big clive, you are amazing. Thanks for a great video.
I have 2 of these units I got from eBay and I love them, best USB I have ever found (and I have dozens of different types)
Great episode. Really learned from it.
@ 25:25 From their Wed page it states
Intelligent Charging
0.5 - 3.5A automatic identification of charging, perfectly fits for your mobile equipments...
Hi Clive a tear down of a clip on guitar tuner would be extremely interesting regarding how it picks up on vibrates and processes as a note.
probably just a microphone behind the spring clip that holds it to the instrument. Maybe it just doesn't have a hole open to the air so it only picks up vibrations conducted through the case, not random other noise. I'm guessing it would be a really boring teardown - a microphone, a chip under a blob of epoxy, a couple discrete passives, and a lcd and a couple leds.
gorak9000 Usually it's a magnetic sensor picking up vibrations of metal guitar strings. But I don't know the details. Clip-on pickups for acoustic guitars with non-metal strings may be microphones though.
I didn't think about that. I was mostly thinking of clip on tuners for other string instruments, like violins, where you clip them to the scroll - pretty sure the guitar tuners clip to the end of the head, by the tuners too, so they aren't using magnetics to pick up the vibrations from the strings, but rather the vibration of the head (or scroll) itself. I don't have any of those clip on tuners - more of a traditionalist, tune A using something (tuning fork, tuner, smartphone tuner app, oboe, etc), then tune everything else listening for the lack of beat frequencies
I'd guess they use signal from piezo transducers achored at one end and left to "flap" with the vibration. Would like see 'cos it's still clever or witchcraft under £10.
LostJohnny I think this is the most likely setup. I know the world we live in....I just purchased one from eBay for 6.50 and it’s fantastic.
3 AM... I should check the length of videos before decide to watch it full ;)
I’ve bought a few things from Gear Best, and it’s pretty typical for things to have random English on them; sometimes it’s just words that were on a design sheet or something, and whoever in China recreated it didn’t know it wasn’t supposed to go on the product itself…
Get well soon. Another great video.
Clive, you can buy a copy of EN60950-1 from "estonian standards" for about 33 Euros which is much cheaper than the £400 BSI want. That will detail hipot testing voltages, allowable plastic flamability ratings and creepage and clearance distances that should be used between the mains and safe side on IT equipment. The standard has been superceeded but for what you are doing that shouldn't be a problem.
If you do buy the standard that device would be pollution degree 2 and installation category II and the PCB (if FR4) would be assumed to have a CTI of 175.
There will be multiple hipot test voltages listed one for testing by the compliance lab and a lower one which each unit should be tested to in production
Looking at the EN60950-1 Standard.
Table G1 Says for an AC supply between 150 and 300VACRMS in Overvoltage Category II the mains transient voltage is 2.5kV
Section G4.1.b.b1 Specifies the required withstand voltage is equal to the mains transient voltage at 2.5kV
Table 5C Then specifies the required test voltage for reinforced insulation with a mains transient voltage of 2.5kV is 5kV (peak or DC)
Section 5.2.2 Then says that for certification testing you would ramp to the required test voltage from 0V and then hold it for 60 seconds. It then goes on to state that for Routine Tests (ie production time test) you can reduce the 60 seconds to 1 second and reduce the voltage by 10%.
Therefore for routine testing you can use 4.5kVDC and hold it for 1 second.
These are very interesting and awesome to see
Great video, very informative clive , regards mark
compressed air to get rid of the dust ball my friend. Love you vids
Nothing would fill me with more confidence than a product names "product schematic"!
That was really interesting. Thank you!
Good to know. I was just about to order from Gearbest! You saved me $$
Hi Clive. I've been going back through your videos. I have a USB PSU (4A) that has started to switch on and off about twice a second and I seem to remember you pointing out a fault in a USB supply that caused a similar thing and saying it wasn't uncommon. In fact I'm sure I've seen the same fault in at least two of your vids - but I'm buggered if I can find them now!
Cheers.
Usually either the low voltage side electrolytic smoothing caps, or the small electrolytic bootstrap capacitor on the high voltage side.
All replacements should be low ESR type.