I really like that you find actual problems, repair them with an inexpensive fix and save another machine from the landfill and the customer from spending 10X as much on a new laptop. Keep up the great service.
@AdamantIT Graham, this video clued me into the TVS diode that is on the "sense line" of Dell laptops, coming from the center pin inside Dell barrel connectors. If that TVS diode blows, it doesn't matter if you replace the Dell charger and the power jack on the laptop. The laptop will still refuse to recognize the charger, since the TVS diode is permanently shorted to ground! Thanks for this video.
@Adamant IT, You are correct on the Name of the Diode! From WIkipedia, "A transient-voltage-suppression (TVS) diode, also transil or thyrector, is an electronic component used to protect electronics from voltage spikes induced on connected wires." Spot On!
Loving the series 🥰👍❤️😎 this sort of work is not within my skill set, but it’s interesting to learn that sometimes a series problem can have a easy and non costly repair preventing unless landfill or getting ripped off by a pc trader etc.
I use to repair a ton of CB radio's that had the same type of protection; most failed due to the mobile radio installed incorrectly, "the diode was a 1 amp straight configuration".
I fully understand you! I am currently working on an MSI GT72VR 6RD and I effin hate getting battery out of it. Need to take off the cooling system off of the GPU and CPU to be able to get mid section off so I can remove the battery O.o so much work :S
thanks for the videos, i'm from Argentina, and i'm really learling a lot from all of your videos; as for the mechanical drive, every time he pulls out his heat shield (the metal cover from that 1TB drive) the one of the same brand and capacity sitting in my desktop makes me shiver.. jajajaja Now Really, thanks a lot for sharing all of your knowledge!!! Sorry about my english
As a fellow tech. I completely second your opinion about servicing gaming lapops. Second only to certain Ultracompacts where everything is stuck together.
True, but all diodes exhibit some form of reverse breakdown, it's whether that's at a useful voltage that matters. Also that diode is there to kill a reverse polarity supply in case a wrong charger is used (though these days almost everything is centre positive on the barrel jack).
Y'know I didn't even notice, I thought the M.2 drive had been pulled by the customer, but now you point it out, it booted right up... Good future upgrade for them then!
@@Adamant_IT My Omen has 2 drives; an m2 boot drive and a mechanical d: drive. It's under a metal shield. Full blown graphics and 32Gb . . . it does the job.
@@jed2055 mechanical drives is not even normal in 2023....only cheap laptops get them....my lenovo legion came with 512gb nvme...and a second 2tb nvme...with 32gb ddr4 ram
Laptop visited repair shops and they could'nt repair that before?why do they call as repair service? They're swap service not repair just swapping bads with new parts.diode did it's job.thank you for sharing with us
More or less, but let's face it, there was a time for all of us where the motherboard was a single mysterious circuit board, and if there was a problem with it, you're done. I'm not in the same league as the big name board repair crowd, but as someone who a few years ago was a swap-service, hopefully stuff like this can show people where to get their foot in the door.
Yea... tbh I don't know how much of it is hogwash. Like, did B&O actually supply/recommend the drivers, or are they just the speakers HP would've used anyway, and they paid B&O to leverage their brand name for a more premium look... Have seen all kinds of audio brands written on laptops over the years.
Love this. Very very helpful in helping me understand several things. My Omen is refuses to power on and I am diagnosing it with this knowledge. Question: Should I be getting a continuity beep across positive to negative on the battery terminal?
If I may ADD to the info re: KAPTON tape: It's tackiness isn't particularly good (in my experience) -- but in addition to not conducting heat, it also ... DOES NOT LOSE IT'S _TACK_ (ability to stick) FROM BEING HEATED -- as cycles repeated on electronics. :)
Nice simple one for a change graham :-D As far as i know impedance = inductive/capacitive reactances with a.c frequency and resistance or loss. You were measuring d.c resistance :-D
@@zx8401ztv Impedance is the generalisation of the concept of resistance, DC resistance is not dependant on frequency, but the resistance of a capacitor for exemple depends on the frequency of the signal,and a simple real number is not enough to contain all the information of impedance (module and argument of impedance are 2 informations stored in 1 complex number) The impedance of a resistor can be stored in a real number and is equal to U/I
Might be worth you investing in Tweezer Soldering iron or possibly just get some 1.5 or 2mm copper wire and make up a simple item that is wired on the iron tip and has two ends folded at 90 degress just lay on the device to remove and bingo gone and no heat damage :-)
Excellent explanation and use of video. Thank you very much. I landed on your video while looking for info about removing diodes from boards. What is the max temp of your rework station?
The problem is relying on a charger & it’s safety circuit . You needed a poly-fuse ( PPTC ) between the diode & input jack . Chargers go faulty , get lost so replacements are need . Normally it ends up as a “No Name” low cost alternative , a random old charger or power brick ;-) “ We have a big box of old chargers one should work right ” What’s 2A 20V A/C output ……………. look the plug fits !
Given we dont know if something blew that diode, i would also put it back on before powering it up just to be safe given its a customers laptop and definitely put it back even if it was my own as that thing acts like a fuse and you never know when current or voltage decides to go nuts and burning multi layered boards is impossible to fix. So lots of fuses in everything is the way to go....
Hi, I have the same computer and I have that problem (I plug the charger and no light)but the solution it's not that diode. I checked the cable where you plug the charger and it's fine also tryied whit an improvised power supply whit no control cable I don't know if that is important but still no life.
I definitely favour your LFC vids but lately they're few and far between (I'm saying that and this one is number 264!) and they're waaay too short. I wanna see you scratching your head and throwing everything you've got into the fix. Your channel is still absolutely compelling though.
Hello sir, i have same model laptop omen and it has little different problem. The laptop is dead, but charging light is on when connected to AC adapter. It can not boot up. What is the possible problem? I checked the voltage on power Jack, it showed 19.5 v. I hope your reply sir.
Another great Video and job done,I have here HP slim 290 no power ,power adapter fine 19V detected,but I have only 4V from the positive pin on the power port. Thats mean the port is faulty or ? Thx.
this is why I always bring to the authorized service center, bad repair shop will replace your things with bad things such as your hard drive, component, etc.
hi i tired reinstalling macOS sierra like you showed on your video. i’m able to install macOS sierra but at the end of installation i get an error that my installation is damaged can you please let me now what i should do next?
Working for a repair center where we see loads of people, all the new people pronounce it Capcom tape. So I know call it the Mega Man tape. Oh and yes, gaming laptops suck to repair. Especially when the user expects them not to get warm.
THANK YOU!!! I've been needing info on diodes and particularly TVS ... Can their status be checked en vivo..? (on the board) or must they be removed to check..? Can I check them with a regular DMM..? Or do you get more info from an LCS ..? One more question: How do blown fuses create connections to ground !??? I always thought a 'blown fuse' BREAKS a connection; not 'CREATES' one... can you elaborate on that please..? Thanks!
The fuse analogy was a little clunky... what I meant was that it's a sacrificial part that's designed to fail during a fault, in order to protect the rest of the device. To get a true answer, you have to remove the diode to test it - but there's not a lot at DC-IN that connects the positive and negative terminals (until after the inrush limiter) so a short on DC-IN has a very good chance of being the diode.
Any reason you didn't show checking the output of the Mains Adaptor before plugging in after the repair? You mentioned they can fail and if it had and was giving out more than the reverse bias of the diode, could well have been the cause. I repaired one recently that was giving 90V output due to shorted turns in the transformer of the SMPS. Same fault symptom, blown diode.
Yea I kinda when with my gut on this one, as hot chargers are pretty rare in my experience. Absolutely right though, would've been easy to plug the charger into the disconnected jack and measure the voltage to make sure it was all normal!
It's always nice to provide the part numbers when possible. Looking at the video, it would appear the diode is marked "BV" (corresponds to a SMBJ20CA, see www.mouser.com/datasheet/2/54/smbj-778392.pdf). This would seem to correspond to a 20V bidirectional (which seems odd, this application would seem to need a unidirectional). The video isn't super clear, even single framing. Can you confirm the number? A "BY" variant would be 24V, but still bi-directional. BTW: for a look at uni- vs bi-, see www.mouser.com/pdfdocs/AND8424-D.PDF
That m.2 sloe screams "I WANT TO BE USED" :p good video Graham, like always! I am a guy who likes to repair stuff but i don't have the knowledge yet, but everyday i am learning! Could this diode be used in a phone as well? Lets say you took the wrong battery from the same brand and the polarity is reversed, you the battery in and noticed that it is the wrong one, is there also a diode? I have this problem, a customer took the wrong battery and put it in what is to be a quite rare phone, a sony ericsson play, a 'playstation' phone, he brought it in because nobody could fix it, i told him i will take a look but i can't promise anything. It has a dead short on the battery pins and charger voltage isn't making its way to the battery terminals. There seems to be nothing wrong with that board though, no blown up components or nothing, would it be a good idea to inject low voltage high amps into that board?
I have a laptop from 2012 that died during a BIOS upgrade. I replaced the motherboard with a SH one from Aliexpress, that one died too after ~2h of use. Both cases the laptop won't turn on when pressing the power button. I wonder if I could send you the laptop to take a look at? I live in Romania BTW :D
you said the customer has replaced the DC-jack and when he plugged in the charger the diode blew. Did you check the new DC-jack first and didn’t show in the vid? my first guess in such a case would that the customer had done anything wrong while replacing the jack and just connected it the wrong way round on the side of the jack.
Ye I checked it at 6:00 just in case! Another possibility is that the diode blew when the old DC jack failed/broke, but it wasn't until a new jack was fitted that power actually flowed and then smoke happened.
I'm looking for a FET on a HP Motherboard named VC089 in a SOT-23 package near the power input. Does anybody which one will be the right replacement?thx
Can anyone point me the direction of fixing my laptop ? I have replaced the Thermal Paste on it and accidentally blew my Screen Backlight Fuse off. After finding the blown fuse and removed it + short the circuit to see if the issue is still there... the screen is working fine... but now the Battery does not charge anymore. The laptop seems to be working fine only when plugged in ... but dies immediatelly when I disconnect the charger... which means that the battery is not charging. I have removed the battery and tried it out in my new laptop (they both have the same battery model) ... I have charged the battery ... but when I try now to connect the charger... the charger's protection kicks off and cutts the charging power. I have tested the battery from my new laptop as well... and the charger cutts of the power as soon as I plug it in. Any advice on where should I start ? Thanks in advance
when you said gaming laptops are a pain in the ass to dismantle i felt that, Dell's Latitude series are also a pain in the ass to take apart btw that white case in the background looks super sexy, what is that? @3:20 mark
Not really a relevant question but a big fan of the videos. I have a z370 Aorus gaming mobo with Ami bios F4. I have never updated a Bios and was wondering what benefit will I get or see. My pc runs great has a gtx1080 32mb ram is there any point?
You might get the new-style Gigabyte BIOS interface, but I don't think you'll see any useful feature improvement. In my experience, there's not much change in BIOS updates on Intel platforms, so I tend not to bother updating unless there's a specific reason or bugfix. By comparison, AMD BIOSes have the AGESA firmware in them, and updating that brings in performance improvements. So on AMD it's worth staying up to date, but Intel kinda polish their BIOS before release and then leave it alone.
love your videos, can you tell if BIOS IC is bad or is there something wrong with the motherboard, I have two BIOS chips (4MB & 8MB) on same motherboard and one of them (4MB) is not retaining data, the other one is fine. can you also tell me why there are two of them and why are they of different sizes?
I'm not sure what the second one is for, seen it myself as well. At a guess, I'd say it might be the EC Firmware, but that's purely a guess. Certainly if the 4MB chip isn't retaining data, it sounds like replacing it could solve your issue.
@@Adamant_IT again thanks for replying, after searching and searching i learned that my bios is actually of 12MB and is splitted. And the ME is of 8 MB and the BIOS is on 4MB flash. Then i was unable to find 4MB flash anywhere so i was thinking if i could use a 8MB flash and write 4MB dump on starting of the flash. But i was unable to get that delivered also, at first i was just using the clip on connector to write to the flash and it was always missing the data. Then today i simply desoldered the IC and soldered it directly to the programmer, and this time the chip took all of the contents. I took the dump again and compared the data and it was identical. But when if resolderd the IC to the laptop again it still won't boot and then i checked the chip was missing its contents once again. I'm so much confused right now. Laptop does nothing with battery connected but when i connect AC and press the power button it starts up and runs the fan at full speed, no lights on the laptop and the only way to turn the laptop off is to diconnect the AC power. [Edit] I was able to fix my laptop had to flash both of the ICs and don't know why but i have to desolder both of them. Not gona lie, I have learned many things from you. I have learned alot from this experience and I also have to finish the documentations which i downloaded for this. Assembling my laptop now. Thanks and have a great day.
Ok wen you have a transient Voltage,a Surge Voltage or an Overvoltage it conducts and bypasses, in mouch the same way like Voltage was to high,right? And wen you have an example vor example? Or a Charger with 19V in a 16V ratet Laptop? Would it short or cant it Handle the current of a wrong charger? If it delivers more Amps also..
It depends on the rating of the diode. Most laptops can handle a "hot" charger, and the in-rush limiter will block the voltage if it's too high. The diode is there to bypass a voltage that will kill something in the laptop. If there's lots of amps, the diode will probably get blown up in the process - but that's still better than blowing up the mobo.
The charger never 'delivers' more amps, the current drawn is always controlled by the load. Current I = V/Z where Z is the impedance of the load. Of course if V goes up or Z goes down I gets bigger, but you cannot 'force' current to be more than the load wants to take. If Z is very small but the source has no current limiting then I can get very large at which point something melts, ideally a fuse, but could be the wiring or a PCB track. That could be what happened to the original DC jack as a sacrificial part.
You keep using the word "Impedance". Resistance is a concept used for DC (direct currents) whereas impedance is the AC (alternating current) equivalent.
