USB Voltmeter BROKEN by BALD HEAD MACHINE - Tea Break Fix

[@pauldurham30]

And this is exactly why corporate interests want to stop self repair. Vince you have gone from curiously probing, attempting to fix something blindly enthusiastically; to inventing a solution. Eventually you will be creating solutions from scratch, which makes you no longer reliant on their solutions. Keep it up, I find it inspiring to see what somebody can do when they don't fear failure and embrace the entrepreneurial spirit. Bravo, cheers, and well done.

[@MrMaxeemum]

The voltage regulator will also be used as the reference voltage for the analogue to digital converter.

[@jessicav2031]

If the datasheet doesn't say anything, the standard for pin diagrams is "Top View"! You soldered it with pins 1 and 3 swapped. The 4...v is the diode drop of an internal protection diode. Don't worry though, every EE gets caught by "Top View" vs. "Bottom View" at some point :)

[@Mymatevince]

I've just revisted this Jessica. On this one it did say Bottom View for TO-92 on the datasheet but I still managed to wire it up wrong 😂 I'm just editing up the revisit video whilst I type 👌👍

[@BuyitFixit]

Great Bodge Vince, and good job on learning how a resistive divider works 👍 Hope you are feeling better soon, oh and the Ultrasound scanner repair / teardown I did is up if you haven't seen it yet.

[@TechGorilla1987]

@8:36 - I don't normally laugh at the pain of others, but I actually gave a hearty belly laugh at this moment. Well played, Vince. Well played.

[@thomasesr]

Hi Vince! The big chip is using the 3V of the voltage regulator as a reference voltage to compare to the voltage and current it samples from the 5V and the voltage of the current sense resistor (the big low resistance one).

[@absinthe4breakfast299]

I absolutely love your videos, they are one of my favourite things on youtube, some of your fixes are very creative and always entertaining.

[@jester6856]

I'm new here... just wanted to say how much I enjoy your videos... It gives me the confidence to try some jobs myself. Keep up the good work.

[@Boogie_the_cat]

Vince is spoiling us with all these new uploads happening so rapidly. I think he must be part cyborg to film and edit these things so quickly. And look at how well he solders the usb power meter components. I think that so-called "hair rejuvenation" device he is repairing is actually some kind of robotic "thinking cap" that he is using to beef up his brain and nervous system. MyMateVince is more human than human.

[@leesmith3502]

Gold! Lol😀

[@Mymatevince]

😂👍

[@rfr653]

Good job mate 👍

[@adrianbestboy98]

Now i'm waiting for that bald machine fix video

[@Charlie_Crown]

Hands up who suspected Vince was going to burn his finger there 🤣👍

[@313rail]

✋

[@Charlie_Crown]

@@313rail 😆👍

[@ekens6344]

If you didn't want to wait, scrap boards with lots of ICs on them are normally a good source for 3V and 5V regulators, e.g. laptop boards and game console boards. Though you might end up looking at datasheets for hours checking what's what! I think 3.3V is usually a lot more common than 3V as well.

[@HavingFunRepairs]

Well done Vince! Good thought process and practical application for using resistors as a voltage divider. You're getting danger close to electronics engineering! Time to build your own circuits 🤣!

[@wisher21uk]

Nice fix and well worked out

[@Jdbye]

That was an interesting repair, a bit different from your usual stuff. Of course these things are very cheap so there wouldn't be much point in repairing it to save money, but it does still make for an interesting video. I imagine these things aren't too accurate to begin with, so being off by +/- 0.05 compared to the other meter doesn't really matter, since you don't know if the other meter is accurate either, and USB voltage can vary a bit anyway, all you really need to know is that the voltage is within an acceptable range. So this is a perfectly acceptable fix.

[@GinandTronics]

I've had two of these and both broke at the usb in end. I did solder them back together but I use a different one now. I know on my new one, if I hold reset while plugging it in a known good 5v power supply, it will calibrate to that voltage. maybe your meter has that same function? have a good Christmas

[@geoffowen7627]

I was half expecting a pile of hair in the meter upon opening due to the device that broke it. 🤣🤣🤣🤣🤣 Merry Christmas to you and your family. 🎄🎄🎁🎁🎁🎁🎄🎄🎄🎄

[@instahawk8422]

So early love all your uploads mymatevince they are a constant source of entertainment and always deserve a like

[@tommorgan7043]

I like your new short detector.

[@skonkfactory]

I think you've got the legs of the voltage regulator mixed up, Vince.

[@Mymatevince]

I've just filmed a revisit video Skonk!!!! Can't believe I did that 🤦‍♂️

[@ralphj4012]

I expect you figured things out, but, just for reference, conventional linear regulators have a typical drop-out voltage of 2V. For a 3V3 regulator you need at least 5.3V on the input. If the input is lower many regulators simply pass the input to the output (unregulated voltage bang is the result in many cases). Some LDO regulators have a drop-out of less than 1 volt.

[@mariushmedias]

It's usually 1.5v or less... 2v is if you want all temperature range, and all the current range. For a low current regulator like the one used, the dropout should be less than 1.5v The problem here I suspect was lack of input or output capacitors (or too low amount for a 78xx series regulator) causing instability or something like that.

[@ralphj4012]

@@mariushmedias Generally (not always) dropout increases with lower input voltages and lower currents (over the same temperature range). With an input of around 5V you would expect a 2V dropout, though the dropout graph in the datasheet is next to useless. Even though it seems the regulator was fitted the wrong way round initially, a correctly-fitted replacement is unlikely to have worked and could have easily damaged the device.

[@thomasesr]

The thing about a resistor voltage divider is that the resistors will limit the current you can draw. So when the chip was connected to the 3.066V it probably lowered the voltage to 2.8V because of the current draw (the chip itself was acting as another resistor connected to ground in parallel with the other) that is why you had to lower the resistance of the first resistors (so that the maths got corrected by the circuit)

[@MrMidnight2236]

Can you do a video on these voltage meters and how they can be used in Diagnostic tasks and in repairs .... i just bought myself one because i remember seeing you use them every now and again ... but i cant remember when or why you used it in various different repairs . Would be nice to see all the ways it could be helpfull Keep out the great work P.s my name is vince as well ( vincent actually but i prefer vince )

[@hugosimoes5119]

21:25 It is also true about everywhere even in here. I really get cheap components from China loads of them where in here, they charge the same just for few quantity plus greedy postage.

[@magnets1000]

The output voltage will change because you are changing the current when it is connected in-circuit as that LDO will be powering the MCU/LEDs. You can also just buy an adjustable LDO with similar specs as a replacement from ebay UK

[@brendonelton]

Fantastic Vince! 👍🏻

[@digihorse6730]

If you are dealing with very low current then the easiest way to drop a little bit of voltage is to put a diode in series with the output (use to be called a watt less dropper) each diode drops voltage by approx 0.7volts.

[@andymouse]

The chip that does the heavy lifting relies on the regulator for its Reference ( Vref ) and bases all of its sum's off that I would bet....cheers and Merry Christmas !

[@tipfox9212]

These L78Lxx regulators need an input/output difference of about 3 V. So if you feed the 3,3V type with only 5V it will not work stable and tends to oscillate. Therefore the strange voltage readings ...

[@Taiwanek]

Hi Vince, You soldered the voltage regulator wrong way around. That's why you're getting a higher voltage on the output.

[@Mymatevince]

Well spotted Taiwanek!!! I have just released a revisit video on this. Apologies that your name wasn't mentioned, your comment came in after the filming was done 👍👍👍

[@ralphramirez7815]

Merry Christmas

[@jobit_joseph]

If you change the voltage regulator to 3.3v, the ADC reference voltage will be changed . That's why the voltage reading is low

[@gedtoon6451]

At 11:40 into the video I noticed that the display modules still have their protective film on! Give yourself a treat and peel it off.

[@Mymatevince]

Ahhhhhh, that's my treat done for today 😂 Both peeled off as soon as I seen the comment! Well spotted 👍

[@renatoscutube]

Vince, it's not really important, but I would like to comment that if you observe the marking on the board, it says "U1" beside that regulator and near the bigger chip "U2". So, I immediately thought - that probably is not a transistor, but some sort of integrated circuit. Anyway, nice repair.

[@Madrrrrrrrrrrr]

Voltage regulators are IC's. IC's just means integrated circuit.

[@gedtoon6451]

@@Madrrrrrrrrrrr Yes. And transistors are NOT IC's

[@catherinemorgan2741]

The superhero of TEC at it again

[@TheSkaldenmettrunk]

Nice one!

[@Awynn0]

Talking from an unfortunate experience with exactly the same USB tester and exactly the same failure.. First off the tester is referencing its readings, voltage AND current against the regulated 3.0V so the more precise the voltage regulator the more accurate the meter will show (I think the main chip is also powered from the regulated 3.0v from memory). The voltage regulator these come with (as you said) is only rated up to 6 volt input MAX so if a device on it's output request fast charge from a capable charger/power-bank, the charger/power-bank will output 9 volts (very common) or more! POP goes the voltage regulator! (over current would NOT as some others are suggesting cause this failure, that would likely just burn up the current sense resistor). I replaced mine with a high precision, low drop out 3.0 volt regulator rated up to 20-30v input MAX I think, (I forget, it was a few years ago now) Surely I must have bought in multiples so I'll see if I can find the rest and see what they were exactly... The USB tester could then be safely used on fast-charge voltages.

[@Mymatevince]

Ohhhh, now this makes a lot of sense as I think originally I did use my Samsung charger to power the hair restorer and that does output 5v and I think (from memory) 9V. I have just done a revisit video on this, as embarrassingly I managed to wire up the voltage regulator back to front. Cheers for commenting on this and sharing your knowledge 👌👍👍👍

[@Awynn0]

@@Mymatevince P.S. I couldn't find the spare regulators I may or may not have bought at the time and the only marking on the one in the USB tester is merely marked "HTUA" and I cannot find any info on that identification but I did label the tester as '16V Max' so I guess that is what the one I replaced it with was rated at..

[@J.erem.y]

Vince, you need a breadboard for doing these experiments. Get it working then solder it up lol.

[@ericrichardson3332]

Also I noticed it's not stable voltage it slowly climbs up very slowly and not sure but may even lower voltage i didn't happen to see if it dropped but did see it go up the longer its plugged in to the power bank could be the reason the readings go up and down on the tester

[@VOLTRONDEFENDER4440]

I have taken that tester apart before and I don’t like this tester because the plug of the usb when it becomes loose it can fall apart! But it was surprise it supported 12v power when I connected to my wireless charger that does up to 12v it does read it!

[@yadabub]

If it uses the same voltage regulator, the regulator will run too hot, and likely fail sooner, as it isn't rated to run at >6 volts. I agree about the USB ports, they are not good quality. Of course one could replace them with better ports.=D

[@VOLTRONDEFENDER4440]

@@yadabub but I did test and yes the tester was able to support 12v!

[@VOLTRONDEFENDER4440]

@@yadabub I didn’t want to replace the port as when it comes off the ground pins of the usb plug is already broken! The metal on the usb port!

[@yadabub]

@@VOLTRONDEFENDER4440 I understand what you are saying, but you are talking about the firmware on the MCU being able to test 12v. That's a separate issue from the voltage regulator driving the MCU, which- while it likely does work at 12v, it probably won't work for long unless it is *not* the same one found in Vince's unit(entirely possible,) or is severely under-specced, which _is_ _unlikely_ to be the case. Keep in mind that manufacturers are constantly changing these devices. Even if you paid for a 5 volt meter that superficially looks just like the one Vince was working on, doesn't mean that it isn't actually a 12v or greater capable device.

[@VOLTRONDEFENDER4440]

@@yadabub the one I got can read 5v 9v 12v and I believe 15v

[@Dg-zj6jo]

so small the componants brilliant vince if it did that to your meter imagine what it does to your hair if you put it on your head ha

[@emanuelgoncalves6099]

In the initial vídeo it's notice that transistor heat enough to dessolder. You can see the joints.

[@thorhammer6040]

What would happen if you put a variable resistor in there? Then you could adjust it to have the correct reading.

[@kayleas5328]

to be fair if that's how that specific meter faults when the usb device you're trying to fix is badly shorted i'd wager having those extra transistors/regulators on hand would in fact be a good idea, imo better to have extras on hand and not need them than to need them and not have them

[@jangerhard4039]

Why not using a ordinary diode to get the 0.7V voltage drop?

[@jochenwuerfel]

A very wild fix 😁

[@PileOfEmptyTapes]

I'd have to concur with the "regulator probably soldered in wrong" theory, as I would not expect a 78 series regulator to even be able to output much higher than 3.2 V or thereabouts with 5.0 V in. See whether you can't get a 3.0 V surface mount 1117 LDO. Otherwise a pack of the original part is probably the way to go, even if you're never going to go through them all.

[@Mymatevince]

Thanks PileOET, I have just revisited this one and as you correctly suggested I DID have it wired back to front!!!!!

[@ahmadkorhani3933]

You soldered the regulator in wrong direction input must be on the right, that's why it gives you 4.1v

[@ahmadkorhani3933]

Pin 1 is the output. You solder it on 5v line

[@Mymatevince]

Well spotted Ahmad, I have just filmed a revisit video on this. Thank you 👍👍👍

[@ahmadkorhani3933]

@@Mymatevince My pleasure. Thank you for all of these videos

[@SidneyCritic]

For low use stuff I stopped buying those ludicrous numbers of bulk parts, because you will die of old age before you use 2 of them - lol -, ie, if it's the same price 10 is usually plenty. You'll need a lot of common value passives, ie, 1K, 10K, 10uF, etc, so bulk is good in that case.

[@daz41262010]

excellent bodge up :)

[@blueskies25]

My repair rarely work but that 'looks' like my repairs

[@PeterHovorka]

It failed because Your Voltage regulator is up to 6V. Some power banks can negotiate 9V, 12V or more with the device to be sent via USB. (Wikipedia: A number of extensions to the USB Specifications have progressively further increased the maximum allowable V_BUS voltage: starting with 6.0V with USB BC 1.2, to 21.5 V with USB PD 2.0 and 50.9 V with USB PD 3.1, while still maintaining backwards compatibility with USB 2.0 by requiring various forms of handshake before increasing the nominal voltage above 5 V.

[@magnets1000]

There are a couple of ebay sellers who list items from farnell stock as singles. I assume you place an order, then the seller orders direct from farnell and reships to you the following day. e.g. Blue sky components on ebay

[@hadrianbole9147]

I would have gotten away with it if it wasn't for you pesky ohm's law 😂😂😂 love your channel mmv x

[@h2ocombolhas1]

Next time use potentiometers to figure out the values then solder the resistences :)

[@Secret_Squirrel_Scottishgamer]

Meet FrankenVolt!!

[@dodgydruid]

Maths does always work out I found, I remember the story about the constipated mathematician who had to work it out with logs... sorry I will get my coat... ;)

[@BuyitFixit]

I always thought he used a pencil 👍

[@travisash8180]

I thought he was an Eskimo and had chaps up his bum.

[@omegahelix]

Your hot air gun sounds like a jet aircraft taking off

[@samuelfielder]

Hmm. Doesn't really make sense. You tested the replacement regulator out of circuit and it produced 3.3v. Then when you put it in circuit it was 4v. If the regulator was overloaded it would be more likely to close down and produce no volts. That suggests that the 5v from the USB is finding its way to the output of the regulator by some other route. Also, you didn't actually report the voltage on the regulator output with the resistive divider in place, nor the voltage on the chip in that case.

[@craftymulligar]

Sounds like operational amplifiers from the forest Mims notebook you will find the formulas

[@TheDefpom]

Wow that is a lot of bad solder joints, ALL of the through holes ones need re-doing.

[@uksuperrascal]

First R1 + R2 = RT ( R1 Divided by RT = Ans ) Times Ans by Vin = V out

[@pjmelect]

I did try to buy large quantities of voltage regulators of different types from china and reselling them on eBay at smaller quantities at a higher price. I encountered several problems, even though I used to sell them at £2,99 for ten devices I sold very few of them and you are never sure what you are getting from China with fake devices, I used to thoroughly test the voltage regulators to make sure they met their spec and found many fakes. I gave it up because it was not worth doing.

[@tebbi67]

Put a Diode on the Vout Pin....that should be 4volt minus 0,7volt.....That should be the 3.3volt you Need

[@PeterHovorka]

Until USB negotiate 9V with end device and blow IC up.

[@tebbi67]

@@PeterHovorka thats for the power supply of the display.....how should it be!?

[@craftymulligar]

That's a high precision device I guess.

[@bulwinkle]

I suspect that the connected device demanded more current than your meter could cope with.

[@defiantgsxr]

Sweet

[@alancrisp1582]

Sour !

[@pi18rtd]

Nice vid! Whats upp with your voice? 🤔 😂

[@DEmma1972]

Some of those solder joints looked very bad to start

[@jasejj]

Very low end Chinese electronics = likely child labour.

[@DEmma1972]

@@jasejj high end products also. We used to send children up chimneys and reduce their life span to 3 extra years.

[@jasejj]

@@DEmma1972 true but something by a recognised company is much less likely to be employing bad practices,irrespective of where it is made.

[@DEmma1972]

@@jasejj you think the children require better training?

[@alnoorratansi9364]

put a diode , it will drop it down by .7v.

[@PeterHovorka]

Until USB negotiate 9V with end device and blow IC up.

[@TheAlphaWoomy]

It’s a “Zeee” not “Zed”! 😋

[@squirlystubbuk]

First of all absolutely love the videos. Second i found an app a while back for the phone that you may be interested in it used to be called electrodroid but has recently changed its name to electrodoc worth a look and if i remember correctly i upgraded to the pro version with no ads and more features for less than a fiver. keep up the great work on the videos and have a great christmas and a happy new year.

[@jonathaningram4672]

Watched loads of his vids, got a problem with a portable speaker, none of the tactile buttons do anything, from what I've researched 1 and 3 pin should be connected and thus continuity should beep but it doesn't, got 3 of them in line on the board all same fault, can't adjust volume up/down select track change mode. Has something else blown silently lol board looks perfect.

[@CrAzZyTheCodingBoss]

Use 1 to get 100ma Use 2 in parallel to get 200ma

[@mitchyk]

That meter showing 6 volts could be accurate and the only reason your ipod is charging is because they also have voltage regulators on the charging circuit. Belt and braces approach as batteries can be dangerous when charged incorrectly. You should know this Vince!

[@xerejuneseve6333]

I hear in the background that someone has to cook, clean and wash clothes while you are soldering.

[@simonwatson5299]

isn't R5 missing?? Or is that just me??

[@TheCod3r]

My current was drawing once, but for some reason they won't let it into art school 😵‍💫

[@ianhayward4386]

Your original calculation didn't work because you didn't take the existing input resistance of the LED circuit into consideration. It will sit in parallel to the bottom resister in your diagram. Comment below about current restriction is also correct, probably wouldn't affect the display, but may have affected the current and voltage readings.

[@coryengel]

That whole meter probably costs not much more than the regulator. (At least on AliExpress… not that I support AliExpress…)

[@lancelink88]

A thermal camera would have found the fault in a second..

[@kennybacchus1488]

USB. Voltmeter. Broken by bald. Head. Machine. Tea. Break. Fix.

[@MrBighead_]

cup'o'tea m8s B)

[@Countryballsworld-2014]

Can I have your iPod nano

[@Random_4400]

Bald head machine 😂

[@bovabova8992]

At this point these kinda videos are more like "trying to make it work by any means" wouldnt really call it fixing anymore

[@markshellard5894]

Hi vince 1st

[@alancrisp1582]

Wow, and this is important how?. 🧒 you have nothing to say or add to the conversation!.........

[@mtbjonny9502]

I cannot recommend these USB meters because they are very inaccurate (internal resistance too high).

[@TheCod3r]

Could you email me your p.o box vince? I'd like to send you a little gift if I can 😀

[@renatoscutube]

Vince, it's not really important, but I would like to comment that if you observe the marking on the board, it says "U1" beside that regulator and near the bigger chip "U2". So, I immediately thought - that probably is not a transistor, but some sort of integrated circuit. Anyway, nice repair.