It would have been beneficial to explain the function of the Bootstrap (BST1 and BST2) pins: The Bootstrap pin on a half-bridge MOSFET driver IC provides the higher voltage required to turn on the high-side MOSFET. This is achieved by charging a bootstrap capacitor connected between the Bootstrap pin and the source of the high-side MOSFET. When the low-side MOSFET is on, the capacitor charges to the supply voltage. Once the high-side MOSFET is turned on, the charged capacitor, which floats on the Drain-Source connection of the MOSFET bridge, delivers the necessary gate drive voltage. This voltage is higher than the supply voltage, enabling the high-side MOSFET to fully turn on. This bootstrap mechanism is crucial for driving the high-side MOSFET in configurations where the source is not at a fixed voltage, such as in switching power supplies or motor drivers. The resistors placed before the capacitors typically serve to reduce the peak recharging current to the bootstrap capacitors. In your case, 0 Ohm fusible resistors were used. It would have been insightful to show the gate drive signal to the high- and low-side MOSFETs on an oscilloscope, as this would have made diagnosing the issue easier. The heating of the high-side MOSFET was very likely due to an insufficient gate voltage caused by the defective resistors. The available gate voltage also limits the output voltage of the bridge (to about 7V in your case)
Funny thing, the other day a customer had an overheating fingerprint sensor on a samsung phone. Never heard of that thing before, couldn't find info about that fault anywhere. At least now I know I'm not the only one who burnt (multiple) times my finger with a power button. And by the way both me and the customer agreed that the dodgy way was the best, so I just disconnected the sensor connector. Good job Sorin
Very thin screen on that Samsung laptop!. I have never seen a power button get hot on a laptop before either, temps was showing as 85 Celsius!. Very interesting video Sorin. Thank you 👍👍
Very interesting job Sorin, especially the botton so hot never seen things like that.. evry time new things to learn that for your teaching bye Francesco Timpano from Florence Italy
Jak dobrze pamiętam te kondensatory są po to aby wytworzyć ładunek potrzebny do sterowania bramkami mosfetów. Są bardzo ważne i często mają rezystor w obwodzie.
20:25 Those thingies are 0-ohm resistors so replacing with a wire is actually not dodgy as 0-ohm resistors are actually the same thing... just a wire :-)
how did the power button continue to work on the Samsung computer after you cut the 3.3v (how did you know which 3.3 to cut and which not? Thank you very much
That 3.3v track is for suppling power to the fingerprint sensor/reader. The tracks size is based on the amount of current they carry, clearly that track was the one providing power to the fingerprint sensor
Power buttons also don't require power, they just momentarily bridge a connection together which sends the signal for the board to power up. Same as a regular button/switch.
Because he didn't understand how that part of the circuit works. The bootstrap capacitor (in series with the 0 ohm resistor) is the power supply for the upper mosfet driver. Critical components for buck mode operation.
Another odd one and a confusing or wrong BQ datasheet or a design which misinterpreted it. BTST2 pin 25 (power to the upper mosfet) shows no resistor on the datasheet and gets its power internally in the BQ via REGN (pin 28) which does show a resistor to VDDA (pin 7). The 0R on pin 25 looks to be overriding the internal LDO in the BQ, but I can't see enough detail to be sure.
I would have replaced two bad resistors at the moment you found out that they both not 0 Ohms , but great video nevertheless. :) Keep up the good work.
Hi Guys, could someone explain how the diagnosis concluded to those 2 zero rsistors? To be taken off and turn into a wire? If I join the members, can I ask such questions?Trying to learn a bit more in depth
i am not electronics man , just electricien. i have a big tv and have a horizontal black line 2-3 cm wide near the bottom of the screen. any idea?? cleaning or just send away?
Hi looking for help with my Lenovo Thinkbook 14IIL Model 20sl, my cpu speed is stuck at .39ghz using battery and plugged in. Sometimes charging doesn't work either sometimes it does. I already tried replacing the charger, tried connecting it directly with no battery but doesn't work because it cuts the charging cable sometimes. But it's just not usable because of the .39 ghz cpu speed anyone encountered this problem already really need help. Not software since I already reinstalled windows and all drivers updated and bios. I'm pretty sure it's hardware but I have mo idea where, it's really tricky because laptop turns on fine just the speed and the charging cuts off. Please help
You should have a million subs by now. Easily one of the very best tech channels on the internet! Much thanks for all that you have taught me!
Proper calibrated disconnection.
It would have been beneficial to explain the function of the Bootstrap (BST1 and BST2) pins:
The Bootstrap pin on a half-bridge MOSFET driver IC provides the higher voltage required to turn on the high-side MOSFET. This is achieved by charging a bootstrap capacitor connected between the Bootstrap pin and the source of the high-side MOSFET. When the low-side MOSFET is on, the capacitor charges to the supply voltage. Once the high-side MOSFET is turned on, the charged capacitor, which floats on the Drain-Source connection of the MOSFET bridge, delivers the necessary gate drive voltage. This voltage is higher than the supply voltage, enabling the high-side MOSFET to fully turn on. This bootstrap mechanism is crucial for driving the high-side MOSFET in configurations where the source is not at a fixed voltage, such as in switching power supplies or motor drivers.
The resistors placed before the capacitors typically serve to reduce the peak recharging current to the bootstrap capacitors. In your case, 0 Ohm fusible resistors were used. It would have been insightful to show the gate drive signal to the high- and low-side MOSFETs on an oscilloscope, as this would have made diagnosing the issue easier.
The heating of the high-side MOSFET was very likely due to an insufficient gate voltage caused by the defective resistors. The available gate voltage also limits the output voltage of the bridge (to about 7V in your case)
very insightful. thanks.
NAH... too long to understand. I prefer the proper calibrated wire explanation
He is actually right appreciate his effort no one shares knowledge like that@@antoniobraz82
9:43 classic Sorin, you got thermal camera but still use your finger to locate heatspot 😂
Funny thing, the other day a customer had an overheating fingerprint sensor on a samsung phone. Never heard of that thing before, couldn't find info about that fault anywhere. At least now I know I'm not the only one who burnt (multiple) times my finger with a power button. And by the way both me and the customer agreed that the dodgy way was the best, so I just disconnected the sensor connector. Good job Sorin
i have fixed my friend's over heating fingerprint button with a dodgy repair aswell. oh yea it was a samsung aswell
Thanks for changing your mouse pointer!
I pressed like after the "remind me charge double" in serious tone. :D
Calibration always works.. Proper fix, we have picture.. That power button issue a new one, nice fix on that. Your knowledge is our Bible...
New Samsung Galaxy Book feature: heated buttons, for a more comfy typing experience!
Fingerprint eraser. Should disable in bios lol.
That was a fire risk!
Well done Sorin, great repair
Very thin screen on that Samsung laptop!. I have never seen a power button get hot on a laptop before either, temps was showing as 85 Celsius!. Very interesting video Sorin. Thank you 👍👍
*Sorin, you can turn off logo display on your usb-C meter in the settings. Then working instantly. Cheers!*
Sorin and Rosin sounds for me like the same 😊
Fantastic. Especially the power button quick fix. 😊
I have never seen a power button getting hot ... that is new 😂
It was probably a "white" hot LED shorting out.😂
😂😂😂😂 same here😅
power with fingerprint reader
Same. This is definitely a first for me
I had the same situation. After replacing the chip to the new one motherboard stopped working definitely Finally I realized that CPU is broken
Would rather have seen the ribbon cable severed than the track on the mobo cut, but another awesome repair! :D
The things with the O on it are 0-ohm resistors. Usually used to bridge two tracks.
boards maker like to use them as cheap "fuses" also.
thanks for u changing mouz pointer
The hot power button mode was KIDS LOCK MODE. You can disable it from BIOS setting
Very interesting job Sorin, especially the botton so hot never seen things like that.. evry time new things to learn that for your teaching bye Francesco Timpano from Florence Italy
Jak dobrze pamiętam te kondensatory są po to aby wytworzyć ładunek potrzebny do sterowania bramkami mosfetów. Są bardzo ważne i często mają rezystor w obwodzie.
This laptop seems to us mobile phone type technology to make a very elegant machine!
I would put the original BQ chip and the 2nd one you tried back onto the board to verify they are good and if yes keep them as known good spares.
Sorin won't do that😂 ever, the laptop it's working and has a picture, customer is happy
@@surenot-ky6sy I repair arcade games and swap chips a lot. It is smart to know if the chip is good or bad. But whatever. Not everyone is smart.
The heated power button is a finger warming feature for those cold mornings! It's not a fault 🤣 🤣
New power buttons to cook pizzas... 🤣🤣
Nice work!, Cant believe the fingerprint reader was on the power button, LOL
lenovo and apple did it too
@@maklogetrich2378 Ok, designed to fail so!
No power button, no hot button.
You are genius. I like your video
Hello Sorin. Really nice repair 🎉 Why this resistors is there i cant understand
Fingerprint button changed mode from reader to eraser.
Power button was set to "Delete Fingerprints" 😎
With respect Marian Otoman ,Constanța România
Hello🤝 what an episode, a large dose of knowledge, hot button and the magic of Master Sorin, I love this channel👍👍👍👍👍👏👏👏👏👋👋👋👋👋👋
Salute again master😇
Good job mate 👍
20:25 Those thingies are 0-ohm resistors so replacing with a wire is actually not dodgy as 0-ohm resistors are actually the same thing... just a wire :-)
someone removed the heatsink from the power button?🤣
Definitely need thermal pad therapy
Haha. Wtf?!
Add thermal pad
That laptop came with liquid cooling for the power button. Instead they installed liquid crystal display. 😅
what about the original BQ chip? was not bad ?
Damn, now I know why they call it ´´Power button´´ ....... it's hot because of all that power 😂😂🤣🤣...!!!! Great video.
30 MINUTES AND UP YEAH YEAAAAAAAAAAAAH
THANK YOU SO MUCH SIR
the best in the end with hot button :D
Another masterclass.
nice repair.
I mean this laptop came with 65W power adapter that charging current is insane
how did the power button continue to work on the Samsung computer after you cut the 3.3v (how did you know which 3.3 to cut and which not? Thank you very much
That 3.3v track is for suppling power to the fingerprint sensor/reader. The tracks size is based on the amount of current they carry, clearly that track was the one providing power to the fingerprint sensor
Power buttons also don't require power, they just momentarily bridge a connection together which sends the signal for the board to power up. Same as a regular button/switch.
Sorin those two zero ohm resisters you checked show no continuity how can you ignore that
great! job well done sir.
I like the Count laugh😂
Sr. Sorin, where you see PDFs of chips Schematics?
Now I'm disappointed, I expected him to put a cal wire over the 0ohm resistor straight to the cap - lol -.
Why did u disregard the open resistors at first?
Because he didn't understand how that part of the circuit works.
The bootstrap capacitor (in series with the 0 ohm resistor) is the power supply for the upper mosfet driver. Critical components for buck mode operation.
@@worroSfOretsevraH still even if thinking not the cause of the problem Odd to find faulty component and then think let's just leave it.
Another odd one and a confusing or wrong BQ datasheet or a design which misinterpreted it. BTST2 pin 25 (power to the upper mosfet) shows no resistor on the datasheet and gets its power internally in the BQ via REGN (pin 28) which does show a resistor to VDDA (pin 7). The 0R on pin 25 looks to be overriding the internal LDO in the BQ, but I can't see enough detail to be sure.
@@Swenserwas an odd one
12:25 in the meantime BQ already smoking hot XDXD
35:48 no more button - no more hot button!!!
LOL. You didn't understand what you watch. 🤣😂
@@Ingatkamote I don't understand you, man. You're mixing up the present and past tense. Who didn't what LOL people these days ...
Great
That screen is sooo thin! Must be easily broken as it's so thin.
made to break, then to buy another.
I would have replaced two bad resistors at the moment you found out that they both not 0 Ohms , but great video nevertheless. :)
Keep up the good work.
I would have been calmer seeing the current drop to 1 amp or zero at full battery charged
proper calibrated power button
Good button for winter...🤭
Hi Guys, could someone explain how the diagnosis concluded to those 2 zero rsistors? To be taken off and turn into a wire?
If I join the members, can I ask such questions?Trying to learn a bit more in depth
You don't have to join in order to ask a question, you can ask how many questions you have during the Sunday livestream
@@electronicsrepairschool thank you Sorin, it's much appreciated, have learnt so much from your channel , will join regardless
If the button is already ruined why not cut the track on the button?
Pressing the power button and we have a third degree skin burn. It's crazy, I can't believe.
Not your 'average' hot-button issue🤣 wow, not a 10 min repair by any means but as always, a very interesting lesson. 🍕🍕
How the hell is the power button even getting hot? what sort of shit design is that. Great repair Sorin. Proper calibrated video yet again.
Put a switch, charge extra for new feature: Desktop Korean BBQ
Pls sorin make type c power squence video.
Hey sorin what happened to that boor probe 😂
Impressive😎
5:30 ... TF is wrong with my screen? oh.. wait... e de la ei :))
why not use scope to see if mosfet switching
Sorin found the "stop looking at porn" button , , , , , LOL
Perfect 👍👍👍👍👌👌👌
You are dah man!
so what happen with the fingerprint censor , is it work ?
Of course not, the power is disconnected
Nice! 😎
If you fix finger print reader, maybe you can charge double.
i am not electronics man , just electricien. i have a big tv and have a horizontal black line 2-3 cm wide near the bottom of the screen. any idea?? cleaning or just send away?
Pressing the power button: Lo0ooL 🤣
My girlfriend wants to know why I walk around saying LOoooL.
6:45 the best question/remark you said in a while :))
Sorin is only working for Pizza, Hey no Pizza no Working Sorin
👍👍😊😊
Hey my fingerprint sensor is not working….. I’m sending it back in for repair.😂
23:24 is he saying big chip? Or bgp chip? I can never understand what he is calling this chip.
BQ chip from the model number
Hi looking for help with my Lenovo Thinkbook 14IIL Model 20sl, my cpu speed is stuck at .39ghz using battery and plugged in. Sometimes charging doesn't work either sometimes it does. I already tried replacing the charger, tried connecting it directly with no battery but doesn't work because it cuts the charging cable sometimes. But it's just not usable because of the .39 ghz cpu speed anyone encountered this problem already really need help. Not software since I already reinstalled windows and all drivers updated and bios. I'm pretty sure it's hardware but I have mo idea where, it's really tricky because laptop turns on fine just the speed and the charging cuts off. Please help
👏👏👍👍
😁😁
no more fingerprints. the customer will use password instead thanks
It is not called a power button for no reason ;)
bqu chip what does this chip do ?
Why does the button have the 3.3V rail then? Led light? Would that mean the led is shorted?
Power for the integrated fingerprint sensor
Funny Fault..🤣
just,remain you to charge double your customer lolz
lol heated power button only samsung
Does anyone have any idea about BH5321LN Or BQ25708 ic and from where I can buy it in India?
Won't that hot button destroy the screen in that corner?
🥸🥸🥸🤓🤓🤓🤓🤓
Tuch id will not work