ANOTHER AMAZON Returns MYSTERY Box from eBay? Can I FIX it?

[@Blu3ManiC]

That potentiometer you’re looking for on the gimbal is a psp joystick. There are psp joysticks with removable tops that are throughhole and smt instead of a ribbon cable. It’s the same one that knockoff joy-con usually use.

[@digihorse6730]

@Blu3ManiC is the value the same though. As it need to be correct resistance to work I expect.

[@VSteam81]

I actually didn't know that a psp used this

[@Blu3ManiC]

@@digihorse6730 resistors can fix that value but i doubt it’s needed for a gimbal

[@Jdbye]

I was hoping somebody would have the answer to this in the comments. As there are not that many different models of mini/slim analog sticks around and products tend to use off the shelf analog sticks either from big names like Alps or clones from Chinese manufacturers, I figured it couldn't be that hard to find a replacement. I didn't recognize it as a PSP stick because the thumb cap is so different, but I guess the PSP's analog stick might've been an off the shelf model with a customized thumb cap.

[@Jdbye]

Even if the exact same model of analog stick couldn't be found, there's nothing stopping you from using a different analog stick if the resistance is the same as long as you can make it fit. A Switch JoyCon analog stick might work for example with some cutting of the plastic shell, not a perfect fix but a working product is better than a non working one.

[@gamerpaddy]

first chip looks very much like a Texas instruments BQ24050. rough pinout, package, everything matches. its a 1 cell usb charge ic

[@eadweard.]

Vince is being modest of course. He actually kickflipped both into and out of that wall ride. Mark Gonzalez was watching and came over to congratulate him personally.

[@Mymatevince]

😂 Gonz!!!!

[@orion310591RS]

@@Mymatevince 18:00 - Dont search "ev4c2pf2", its two words. Search "ev4c" or "2pf2" or "ev4c charging chip" or "ECC Easy Chip Charge". Its common charging IC from what I can see.

[@Boogie_the_cat]

4:42 Vince made a nice pun with the baby doppler: "let's see if there's life in there" LOL. I'm much liking these mystery box fixes, sir. they're fun, mysterious, and also seem to be honest faults, which are the most fun. Please keep them up!

[@Gottogetthere]

Mentioned before?, home baby Doppler's not recommended for any use, not reliable, induced stress for lady, use your emergency unit if concerned for baby. Trash it

[@rfmerrill]

18:00 The pinout looks like it lines up with the texas instruments BQ2404X battery charger, though that's certainly not what it is. There are a whole bunch of 10-pin DFN single-cell lithium battery charge chips out there, but you'd have to compare each one against the circuit that's hooked up to see if it's a viable replacement as they can be quite different from each other in terms of how they behave.

[@oldman1944]

I think a lot of manufacturers get parts with their own part numbers. Sony use the BQ charge controllers in their speakers but with Sony part numbers. Almost mpossible to search for of course.

[@miro_trendafilov]

When Vince uploads, I watch! Really liking those Mystery box videos!

[@ralphj4012]

Well done, as always. What surprises me most is that these sellers must be taking a major hit re the postage costs, I'll guess at least £10 and probably nearer £15 for that box. The charge chip (EV4C) in the JBL speaker looks to be an NXE knockoff of the BQ24040 or BQ2409 charge controller IC (which JBL use in their other speakers), but, needless to say, do a pin-for-pin, makes-sense check before fitting one.

[@oldman1944]

Sony also use the BQ charge controller ICs in their Bluetooth speakers, but with different part numbers.

[@ralphj4012]

@@oldman1944 Interesting, thanks. The BQ series has been cloned by a number of manufacturers, all of which use different numbers. As long as Vince does a pin-for-pin due diligence and selects the correct version to match the battery NTC value, then all should be fine, he says confidently.

[@Isekai_Fan]

I was just going to recommend that one! Great post!

[@minmogrovingstrongandhealthy]

The last time I bought a box full of tech, it costed me more then 50 euros just for simple delivery (2 days deal) while the contents inside that box costed me 7 euros. Just to put into perspective wtf is going on. XD The very same reason why I opt out of buying things if A) is not close to me B) I have no means of picking it up myself or someone I know to deliver to my place C) it needs to have far greater value on the long run for me to bother invest money and time in it Sometimes even if it's given for free I refuse to take it since the transportation fee and time wasted on it doesn't make sense for me to jump into such things.

[@kataraluna8417]

mine says mine says NXE 098 AJ7E on my JBL Go 3

[@Leonvolt28]

I really love these fixes. Its so much better than the "untested" ebay things that someone already looked at.

[@Pedro_MVS_Lima]

I just love your enthusiasm on attaining these victories (namely with the gimbal). I completely recognize it, even if the result doesn't justify the investment in time and effort, there's that satisfaction of being able to return an object to working condition or at least to understand why it isn't working , instead of just going "It's broken, trash it". Cheers!

[@theatheobhv]

Have you ever considered doing a Repair-Café? There’s one in my hometown every two weeks. People come in with there broken items and a couple of people try to fix it. And there is coffee too of course. You’ll get a lot of unknown stuff to repair. Btw. the people fixing the stuff don’t charge the people it’s a kind of neighbourhood help.

[@cowclan3382]

its so cool! never heard of it

[@Mr._Mythical]

Now I want a repaired café to be mandatory in every town and city. It sounds like such a good idea, but nobody wants to do it at all

[@theatheobhv]

@@Mr._Mythical Well, here in Bremerhaven it works out quite well. They offer it at least every month.

[@GarthBeagle]

Really enjoying these mystery boxes! 👍 And yikes! 14:00 we gotta get Vince some better leads for his multimeter ❤

[@Mymatevince]

Thanks Garth, I do have some, I just need to find them and fit them 👍

[@Boogie_the_cat]

This is a perfect way to start my morning. It sincerely puts a smile on my face to wake up to a new MMV fix-it video. Speaking of video length... I for one love the longer format videos. I realize it would be more work... but if you want a longer video, but you get more views from a shorter video, maybe you can release a long version and a shorter version. Like I said, I realize it makes for more editing work... but I believe many of your long term subscribers would love to have longer videos. I was excited to see the runtime of this video, personally. No bandage on the finger anymore. Congratulations.

[@Mymatevince]

It actually takes me another half a day to get these videos and the car ones) down from 60-90 mins to nearer to 45 mins. My views tend to be better on shorter videos. I used to do a long and short versions a few years back, but overall views tended to be the same. Strange really as I thought having 2 versions would bring in more views. I think it is more KZbin not pushing videos with lower views maybe👍👍👍

[@markvandesande8855]

Use the ultrasound to find noise faults on your Rolls Royce Bud.😊 Hi just say you did a standard battery bms reset shorting the two pins. The battery went to low to charge and only way to charge again is to do the power reset on the bms chip because it latches off.😊😊

[@dodgydruid]

I did a Vince worthy bodge yesterday... I found in a Salisbury charity shop a metal articulated arm for a few quid and I modified it with some old GoPro brackets to take my USB microscope and spent today road testing it after setting it up on my workshop PC, hands free and decent viewing and all it took was some old brackets, some dremeling, a bit of epoxy meaning I can now do microscopic stuff finally yay.

[@Mymatevince]

Well done Ian 👍

[@mikeselectricstuff]

Zero volts from a lithium pack usually means the onboard protection chip has tripped, due to either undervoltage or overcurrent. This gets reset when a charge voltage is applied

[@Mymatevince]

Nice one Mike👍 Thanks for helping.

[@michaeldcullen]

With the photo printer, you effectively reset the BMS which had shut down due to low cell voltage.

[@BuyitFixit]

Another Great Video Vince! 👍. Those amazon boxes do seem to be fairly good value, and are great fun. Thank you kindly for the mention, you're a real gentleman!👍👍👍

[@MrEwool]

And a well deserved recommendation 👍

[@BuyitFixit]

@@MrEwool Thanks Morten! Glad to see you here too 👍

[@MrEwool]

​@@BuyitFixit of course you can't say you watch repair videos and not watch Vince 😊

[@brutlern]

The tiny printer is really cool. I might get one, just for the novelty.

[@VOLTRONDEFENDER4440]

I think that short on those pins of the mini HP printer was from + to a Resetable fuse! I think a fuse on that charge chip somehow tripped for whatever reason and you shorting the + to thet resetable fuse line Reseted the fuse!

[@mahlapropyzm9180]

Could be overcharge/overdischarge/short ciruit protection. usually on a battery protection board and power off resets it (often involves detaching the battery and reattaching). Maybe Vince's tweezer action somehow did a similar thing o the onboard chip.

[@VOLTRONDEFENDER4440]

@@mahlapropyzm9180 you mights be true about that although the battery cells I didn’t see a temperature sensor

[@mandragor85]

24:00 this remind me of an earlier project of yours where you did short out the battery managing unit and it start getting a charg in it again i do not remember exactly what it was maybe a battery for a tool or somthing like that

[@redtech6732]

think i found it. the joystick name soundwell RJ12 series

[@MrBrainFear]

Yep I located that one also the logo is very similar

[@Amelia10168]

Vince I really enjoy your videos I only started watching them on April and I am hooked they are always interesting to see you taking the items apart to try fixing them.

[@Mymatevince]

Thanks Angela, really glad you enjoy them 👍

[@nunocac]

Hi Vince, on the HP Sprocket and that battery mind boggling issue is normal, i work in the battery manufacturing and i can confirm that certain battery PCB's can go to sleep over time to self protect from over discharging. Some batteries will require to be plugged in to a computer with the adequate software some others will just require a burst of current.

[@djdaddy8080]

I've encountered the same problem with lithium Ryobi batteries 0:26:37. Some gate get's latched open when the batteries are too deeply discharged and a quick short pops the gate open. Definitely not recommended for people that don't know what they're doing.

[@kevrosbane]

30:52 not sure what resistance that is but if its 10k ohm you could use a adafruit 2765 it looks the same size as in the video.

[@RandyDarkshade2]

I've just bought another one myself. I just like the surprise aspect and find it fun.

[@miro_trendafilov]

You could totally print small stickers and cards on some sort of stock or thick paper with that printer and maybe sell them signed? I think it's a good idea, I'd totally buy a MMV signed card.

[@NanoMine]

Unfortunately normal paper wouldn't work in that printer as it uses a special paper to print. That printer doesn't take any ink.

[@UserUser-ww2nj]

@@NanoMine Thermal paper??

[@ovalwingnut]

I'm a lilttle late to the party but I just wanted to say; You are a very, very honest man "My Mate Vince". You could just be the last one on planet Earth Cheers from So.Ca.USA 3rd House On the Left.

[@booboyBL]

After your previous video, I also bought a £50 returns box. There were a few items that were an easy fix, but none of them particularly useful to me. I also got a power bank with the same fault as yours (it was also the same brand but a different model). Unfortunately, I could not get into it without destrorying the case. I got over 100 AA alkaline batteries too. I may get another box in a month or so.

[@technixbul]

17:57 just put in one of those TP4056 small boards and hook the battery through it, DONE! ;) EV4C in DRC 10-pin package may be either BQ24040 or TPS40210-EP depending on schematic and function, try to trace some pinouts for it on the board. A TPS40210 is a boost converter that may be set to control charging current and voltage and soft-start function. A fix that I suggested is preferable over guessing what it is, it may be neither of them.

[@sajjadkhan1986]

I was thinking exactly the same thing. When you cant find things, improvise...

[@heatshield]

Your friend used a physical film camera, which he then somehow digitized and sent to you, which you brought to an app with your phone, to print out from a mysteriously fixed pocket device. I call it a win.

[@coolissimo69]

And that is what I call a box of surprises. Well done really enjoyed this one.

[@snafu2350]

WRT that last fix with the hearing speaker, you could have used a cheap sewing needle/pin to provide the strength, then sealed the end projecting into the jack socket with mastic/hot melt or WHY; if you're unhappy using metal, there are novelty cocktail sticks made of plastic that would have done instead (with less strength ofc). It requires a steady hand with a jeweller's hand-drill to make the holes in the jack (esp centring), but I'm sure you're up to that with your microscope :)

[@DEmma1972]

even if the box was doctored, still a good bit of stuff for you to work on. Loved the camera gimble, give me a shout if you can get it fixed lol.

[@CR7hg]

That picture on skateboard was great. Like a proper photo session

[@aaroncampbell113]

I reckon accessing the chip from the JBL speaker would be fairly easy, since JBL seem to have 1000's of them. It's probably pretty common. When replacing it on the PCB you probably wanna get a pre-heater, which is essentially a convection heater that suspends the PCB over the heat source warming up the whole board preventing localised heat from running off onto all the copper nearby. Then you can use your heat gun to solder the chip back on with some confidence you've reflowed the big ol ground plane underneath. Hard to check unless you have an X-ray machine handy.

[@frozendude707]

17:15 On those small chips it is often the second line that is the model number, and looking for "2PF2" there was one company in Beijing called Niceway (北京耐芯威科技有限公司) that claims to have access to some stock of it.

[@albert_vds]

You can't test batteries with a multi-meter and conclude they are okay. The battery needs to be under load to read an accurate potential. Clip 2 alligator wires to a 100 omh resistor, 1 to each lead, and then clip 1 of the wires to the positive probe and the other to the negative probe of the multi-meter. Not putting it under load will give a higher voltage than the battery can give while under load. So it might seem it's reading as 1.5 volt but when under load it might give something bellow 0.8-1.0 volt, which isn't enough to run anything.

[@MasterJediSean]

A similar thing can happen to the fan circuit on a nintendo switch, thecod3r has a video called the magic smoke or something like that, where he shorts something on the fan circuit and boom the fan starts working. so it is very likely you have stumbled onto a similar issue where an ic gets locked. good work Vince!

[@tonysheerness2427]

You hit the jack pot with this mystery box. However it is your skills that bring them back to life.

[@AmazingDX]

The JBL Go speaker could be saved if you add a tp4056 charger circuit inside it. As for the gimbal, I have Zhiyun Crane M2 with a very similar joystick to yours which got broken, luckily I have a Moga Pocket joystick which uses the exact same part, took the stick from the Moga pocket, installed it on the gimbal and it works beautifully.

[@ninetailscosmicfox5585]

I am looking to start repairing things, and this is a juicy little hack. Thank you so much for showing this off!

[@DrywFiltiarn]

As to the EV4C marked chip in the JBL GO3 unit, I suspect that it will be some obscure Li-Po charging chip, at least from the major electronics brands there's not a single one I was able to find in this package with the given IC marking code. If you would be able to reverse engineer however the components connected to the IC and the pins they connect to, I imagine there will be a drop-in replacement available from a reputable brand.

[@mikeshaffer1169]

For the gimbal potentiometer. Looks to be a Soundwell RJ12

[@The-Weekend-Warrior]

You silly sausage :D:D I loved the segway to the PCBway segment :D:D:D:D

[@Za_TA]

16:50 HAHA Nice. I Have actually came to This Channel from Him. He, one of his video mentioned about your channel. I enjoy watching Like these repairs.

[@j1mgg1234]

I also got the hp sprocket in a returns box. Replacing the battery was the ifx in my case, but i dont have your skill to properly troubleshoot the electrical side.

[@philsinclair]

I want to purchase a signed print of Vince on the Skateboard 😂😂😂

[@chrisplatis6376]

16:45 i know that my idea is kinda crappy but if i had this i would totally remove all the components and completely isolate the usb c port then connect the port to the tp4056 module and then the module to the battery!!

[@frostyslife1729]

Ok I know this is gonna be a great vid cup of tea ready !!

[@spiders-tours]

Do we need some sort of law where manufacturers use only certain parts for standard functions as part of right of repair. Especially that voltage-checker thing, that should be readily available on eBay. Perhaps some sort of product fix rating as well 1-5.

[@rfmerrill]

If a lithium battery is reading significantly below 3 volts, I would not risk charging it unless I'm sure that's the result of protection circuitry and not the *actual* cell voltage! Attemping to recharge a ltihium cell from such a deep over-discharge would be dangerous. However in this case I think the battery has internal protection that tripped and it was likely just in a deep discharge, not an overdischarge.

[@gorky_vk]

"It look like short, let me plug in this freshly charged most likely high current capable li-ion battery to it just to be sure" :))) When you can't find replacement charging controllers you can always use tp4056 module inside and just wire everything to it, it's look like there is enough space inside of speaker for that. Original is most likely something from linear tech, LTC40xx. But I'd just replace it with 4056.

[@patrickcraenen5163]

The HP Sprocket photo printer probably has a protection circuit that disconnects the battery as a safety measure once the voltage has dropped below 2.50V. You probably reset the protection circuit by shorting the 2 pins otherwise you would not be able to put a new battery in.

[@drcarrot415]

Nobody: Absolutely nobody: Vince: just randomly pulls out an epic pic of him doing the nastiest wall ride to test this little printer

[@AeiKei]

Seems like Vince will start digging thru loot boxes. Amazing fixes. I guess most of the stuff is suitable for tea-break fixes

[@CLC-1000]

Lovely to see this series back. 👍

[@johnclintonmusicandmore]

Good looking dog that’s a cool little picture printer

[@petertrevena804]

I love these Amazon Returns Suprise boxes. And some of the items make a great video with you trying to fix them👍👍

[@patrickcraenen5163]

Hey Vince, I hope you have a fire extinguisher nearby when trying to charge fully discharged Li-ion batteries. It is very dangerous to charge fully discharged Li-ion batteries, they can easily become unstable and ignite and explode. When a Li-ion battery is discharged below 2.50V it is no longer usable and dangerous.

[@AnonymousRepair]

great video ,👍👍👍👍👍👍👍👍,Thumb slide Joystick ,b10k-1, no luck yet on the other parts

[@Mymatevince]

You legend AR. The potentiometer is a Soundwell RJ12 potentiometer, but unfortuantely I cannot purchase them anywhere...So I bought 10 x b10k-1 for £8 from AliExpress instead. Hopefully it may do the job. Nice one AR 👍👍👍

[@AnonymousRepair]

@@Mymatevince you're welcome, Anytime

[@scotthewitt6047]

Sometimes what i use is Google Lens App take a picture and it will search for that part or symbol. Doesn't work all the time but sometimes you can find that fart like on the Camera thumb stick.

[@toolsarecool]

Nothing like finding that fart with Google lens! 😂

[@j1mgg1234]

Thats how i found the potentiometer

[@rambledogs2012]

7:48 What did you do with the finger there?

[@frankcarpenetti5776]

I think Ralph J is on the money with his suggestion. I was going to suggest the BQ2409 Texas Instruments series. Need to look at the typical app sheet and see if it matches? Like that printer. Cool.

[@leseriath]

Hi Vince thanks for another great video👍🏻 I spotted the first item you have taken out of box is the Pure discovR smart speaker I have one that had no power and got it working again but with alot of trouble and it's really only a temporary fix by cutting of a portion of ribbon cable that was blown out it's contained inside the rubber shroud that expands and contracts when it goes up and down. You may not have this problem with yours but incase you do I think this could be the cause it seems to be a design flaw! Good luck and keep the great videos coming thank you👍🏻

[@TheSkaldenmettrunk]

Love that and the fixes won. Nice! Hope you will get the chip and the pentiometer.

[@mitchellhw2006]

On the pocket printer, can you charge a 8V LiPO using a 5V power pack? I see no boost converter on the PCB. It appears to be a USB C connector. A true USB C charger supply can negotiate with the load device for both current and voltage up to 19V DC. Try a laptop USB C charger brick. You will see 19.2VDC, not 5VDC.

[@joawesome2319]

Hey Vince. The ohm reading on your lead may always be different due to your multimeter dial switch. At least on my multimeter, sometimes my leads show 0 ohms, 4 ohms, etc and when I fiddle with the dial switch, it changes. So maybe your multimeter can be similar to mine.

[@uploadJ]

I had a pen-multimeter with a slide switch and it was necessary to disassemble and scrub the switch contacts with a swab doused with WD-40, after which all was good again!

[@binkyboobosh1]

The usual fare is knackered caballed earphones and low rent Bush radios. Also, misc specialised item and the old chestnut....blue tooth speakers.... For you, it's a great idea. You get to make interesting vids. For most, you end up with a load of broken crap that's not worth spending a few days trying to fix before it ends up in recycling..

[@DankerTVTimeCapsule]

vince and his magic hands getting that photo printer back to life.

[@wollaminfaetter]

This concept is genius. Love it.

[@andyyoung5606]

Love the cabinet jumper wire 😉

[@AndyDo]

I have an LG monitor that has an eeprom with bad code. Whenever there's a power outage, there's a chance it will just not power on. I have to bridge vcc to one of the pins to pull it high and then hope that it's on a clock cycle that refreshes it. I wonder if the charge controller has a similar bug.

[@MrCaptainbilbo]

Since the first video I have bought 2 boxes from the seller both filled with decent stuff I like to fix items when I'm bored silly. 👍

[@erbigimbi9903]

What is a good link for buying them?

[@supergeekjay]

That's the issue with some little unknown brand chips. They're either not available, or available only in bulk packs for OEM. So annoying when you only need one chip!

[@Alzheimer_boy]

When you check out the datasheet of any chip, you'll find a list of similar alternative chips. Often you'll be lucky to find an other one that works as well. But please doublecheck the pinout and chip peripherics. Because some chips need a little other resistence, capacitive or inductive values of the cercuit to deliever the same funktion. But you might be lucky to find a chip wich costs a little more but you can buy them in low quantities. They are also likely to be of better quality, because the manufracturer wants to safe money. Wich is 100% legit. Because the same product can cost waaaay more when they would not do this.

[@rfr653]

Good job mate 👍

[@talon4x4]

Absolutely love these mystery box videos!!

Amazing things that do not exist in Patagonia Argentina. ¡Gracias!

[@adiposerex5150]

Your videos are very entertaining. Thanks for the efforts.

[@sayantanbanerjee4390]

For the JBL Go speaker the IC name is 2PF2 which is the charging IC. Hope this helps.

[@nhansgoofyvideos7581]

I guess if there was enough space inside the JBL speaker you could jam a TP4056 board in there to charge the battery, in the worst case scenario?

[@BuyitFixit]

I had been thinking the same thing 👍

[@michaelsimms76]

Might look into one of those hearing helpers as im not quite ready for full on hearing aid yet lol

[@uknavynige]

Your such a clever logical bloke, fascinating videos although a lot of it is beyond me how u figure out the problems 👍

[@mcac5150]

I love this type of content, please do some more box returens videos!👍

[@thadofalltrades]

Those fixed items will make cool giveaways and you could even probably donate that hearing aid device to someone who needs it.

[@lindastone6868]

Try photographing the part and doing a reverse image search

[@frankromero5581]

Your amazing man . never give easy ok . your friend from the US . 🐢

[@Trydon-vz8tq]

Can you please send a link where you purchase these boxes.

[@HavingFunRepairs]

Interesting, Was the short you produced for the charge port of that mini printer across a data pin?

[@Mymatevince]

Well it was between the temperature pin and the positive. From memory on the Nintendo Switch if you want it to work on 2 wires (just the + and -) then you have to short the temperature wire to ground, that is why I thought shorting it to ground here might make it work. It didn't, but shorting it to positive did!!! Very strange, I presume I have blown open something yet it is charging (on initial testing) perfectly. Thanks for watching Shawn 👍

[@HavingFunRepairs]

@@Mymatevince you probably mentioned that and I didn't catch it or was distracted while watching. In older smart phone technology the charge port required the data pins to be shorted to each other to allow faster charging (1A vs 500mA) as an example. In a clutch I would strip the charge cable and twist the wires to those pins together if I needed a quicker charge in an emergency type situation. That was the why behind the question.

[@Mymatevince]

@@HavingFunRepairs 👍

[@jrsc01.]

great segue Vince!.. 6:07

[@JohnGotts]

Look at the layout of components connected to the IC. Surely you can find a compatible 10 pin charge chip based on that.

[@digihorse6730]

NTC “Negative Temperature Coefficient”. PTC “Positive Temperature Coefficient”, Thermistors. NTC resistance decreases as temperature increases. PTC resistance increases as temperature increases. Almost certain the device is a battery overheat detector. Is it possible the battery overheated the NTC device somehow made the IC go into protection mode and it took the “shorting of the pins” to reset that

[@nephrusdf6]

make a new hole for that external battery charger you were using and fix the bt speaker by wiring to the connector. I think it was the tp4056, or replace the connector that is there with a breakout board and a spacer and wire to the tp4056 and then to the battery connector

[@frankromero5581]

Great picture .

[@marcus_cole_2]

I said this before but what looks to be happening for most of your products is people are plugging them in the wrong way causing the chips to either die or trip.... For example if you put an usb-a upside down on a chip it can trip the system and lock it into a safe mode where you cannot use it and you either have to charge it or decharge it or in my case with my battery pack put all plugs in and charge it quickly and take out the plugs and it's back to normal this is why we went to USBC

[@elegri]

You might have damaged the pin of the charger IC of the printer when shorting to +battery voltage (I assume the IC is supplied by 5V from the USB port). To check the functionality, you. should short the NTC to ground to trigger the over temperature protection.

[@masoudmontazery907]

Good luck sir 🎉

[@brody6634]

Love how Vince says aluminum. 😂 6:57

[@MarkPentler]

Aluminium* 😅

[@brody6634]

@@MarkPentler aluminum* 😝

[@eathenalexander2836]

Vince looks so cool on a skate board

[@samuelfielder]

It seems you need a lithium battery charger ic which takes 5v usb in, and outputs 8.4v (i.e. is capable of charging two cells in series) in a 10-pin package. It will need to have an integrated voltage boost. I looked long and hard for these but could not find any that were simple enough.