Excellent repair and a long one means more fault finding and we get see your thought process as if we are with you looking at the board. I already have a background in laptop repair from 20 years of it but watching your videos has taught more than those years from all the videos you have done over past few years. Thank you Sorin 👍👍
I just discovered your channel the other day because I was given a bunch of broken laptops and researching how to repair motherboards. I've watched at least a dozen of your videos and subscribed. Thank you for your content and education.
Fatigue voice "we have picture !" Congratulations Sorin 🎉. It's a very tough analysis motherboard job. You deserve a Nobel prize for finding the bad resistor 😊. Just to share. Last month, I got exactly same fault. Main power rail 3-4V. No short Acdet 2.6v Regn 6v. Change ic not working. Then, I tried increase the acdet from 2.6v to 3.3v. And suddenly 25v appear on the MOSFET gate. Charging and can work perfectly. Although I'm pretty sure it doesn't make sense. But I'm happy it works 😊
Sorin, I know that you prefer linear power supplies but I recently bought an OWON SPE6103 as it provides a graphical display of voltage and current in real time. I was working on a unit that was pulsing it’s power in a similar manner to this HP laptop and this could clearly be seen on the SPE6103 display current plot. They were very short current pulses that could otherwise be missed. I own a few different bench power supplies but the graphical display of voltage and current over a period of 60 seconds per trace makes this inexpensive unit very useful indeed.
very nice lesson thank you so much Sir Sorin. I've opened my own repairing shop and things are going very well. I've learned much from all of your videos and i always follow every video you post am so grateful to have you Sir you're the best teacher ever. thank you for being so patient with me and others when i used to ask some questions and you would respond. I pray for more Years and health
Wish I did this, 43 now so maybe too late in life but If I ever get early redundancy and a nice pay-out from my current job I will 100% go for it. The boards I cannot fix...well I know this guy on RU-vid, think his name is Sorin 👍👍😊😊
Negative multimeter probe looking tired lol. I bought a Proster Multimeter Leads kit from Amazon over a year ago and I highly recommend it. 0 ohms resistance and many useful add-ons.
I don't know how no one noticed the 10 ohm resistor that burned when sorin touched the pins of the BQ chip with tweezers... 7:58 (because the laptop was live) and you can see the resistor breaking, later under a microscope while changing mosfet, you can also see the burned resistor, and he didn't notice it until the end of the video
I dont know how did you manage to find out what is going on there but you are the real MVP here .... btw that was the saddest "we have a picture" Ive ever heard from you. You sir deserve a fine coffee after this repair
So, if I understood correctly, from the ACDRV PIN on the laptop there's two resistors in series and then two caps in parallel to the mosfets, and on the datasheet there's only 1 resistor. It would have been nice if Sorin measured the resistances of those resistors, maybe the one next to the mosfet was dead.
sir . . plz up load the full video ..we learn how diagnose the bourd i open a shop on my town and i work great >. It's because of you . thank you master
Hi Sorin, great lesson for us with this strange case, thanks for sharing, please whwn explain on datasheet use a mouse pointer bigger & colored if possible or is hard to follow your explenation... thanks 🤗🤗bye Francesco Timpano from Florence Italy
Salut Sorine,daca esti de acord sa primesti cadou un DMM Agilent 34401 A,trimite datele de expeditie,platesti transport si taxe. Functioneaza minunat,am facut upgrade si tu mertiti cel mai mult,in opinia mea.Multumesc pentru tot.
(2:18 - 2:20) Detachable GPU (easy access). (4:02 - 4:06) Yeah. Beautiful design. Completely agree. It seems that finally! HP engineers start using their brains...
I have an HP X360 Ryzen 5. Insurance write of paid $75 nz plus shipping, Goes well very good laptop sum case damage ect but that is no problem. The problem is if the battery drops below 25% it shuts down or when the charger is connected or disconnected it also shuts down. I am guessing but looks like you have found the issue with the hp charging not charging and intermittent shutdown. Makes sense that if the battery control ic is not seeing the main voltage properly then start up charging and other issues will be present. Thanks for sharing your content.
Nice job! Today I had crazy job - 12V power supply, no burn marks, everything clean and intact... but somehow it got 200k 1W resistor to became open! CRAZY! How could that happened? I dont know, its insane!
Great job Sorin this one ir really hard , but I think resistors do not short rather they make open circuit or higher resistance than the actual value respect!
Great job! I Had similar issue with a laptop a while ago I think that resistor supposed to be a low resistance ( like a fuse) this just my experience though . Thanks Sorin
In production some times You must make some changes in order to solve uncommon issues. The resistror introduces a delay on the check. May be this motherboard works fine but other not.
Of course the resistor wasn't shorted, actually he shorted it to make the laptop work. It may have had an increased resistance, or maybe a smaller resistor (or a short) just helped the laptop to start, even if that resistor was still good.
@@walter.... This fault still took a lot of finding, my question is why that resistor was there and unless it was only a few ohms then shorting it out is likely to cause more issues in the future. This was not the way i was taught to repair faults.
I have a repair in right now that’s like this. The laptop starts just fine on battery but shut off in windows. It starts just fine on the charging port but shut off when it gets to windows. The entire laptop is testing fine but I just can’t find the issue.
I’m really confused. You said the resistor was partially shorted, then basically wired the capacitor which totally shorted out where the resistor was. I’m more tempted to think the capacitor is in fact faulty, not passing enough of a power on start up pulse, to the gate (which was also attenuated by the resistor), by shorting the resistor you made that startup pulse higher. If that capacitor continues to slowly fail the laptop will return with the same fault. Unless I have totally misunderstood this fault.
Maybe the resistor was going OL instead of short. I mean, maybe, instead of a 200 ohms resistor it was floating around 93,6k ohms. Then the voltage would be the same, but the current reaching the gate would be too low to activate it - I'm not sure if the gate needs any current at all to be activated, though. If it doesn't, what's the point of that resistor?
The HP Z-books also support the Intel embedded GPU, so maybe the screen would have come on with the NVidia GPU removed? Also the zbook G2 and G5 I have owned both support a HP thunderbolt docking station that has both a USB-C and DC plug that are ganged together and perhaps it supports charging also over the USB-C? (in fact I was playing with an Apple compatible thunderbolt docking station and the Zbook5 indicated it was charging without the DC plug). So maybe that resistor is in circuit there to link up to the USB-C input?
@MrBjarnevik I had to use a compatible Thunderbolt cable with the OWC Thunderbolt 3 85W PD dock, a regular USB-C cable didn't have the same effect, but this fiddling around was with a G5 Zbook which is a bit more modern than the G2/G3. Anyway it was just an experiment in case the HP dock with ganged connectors fails.
maybe i'm understanding this wrong, but that resistor seemed to have been pulling the voltage down, so it actually has risen in value instead of being partially shorted? how am i getting this wrong?
Hi guys, any idea what air speed and temperature is used for such tiny component like the resistor to take off so fast without knocking out all surrounding components?
@@sakis1991 Thank you Sakis, Ι have the Atten Air Station and anything above 45% air speed it blows off all surrounding small components once the solder starts melting or moves them off the pads
@@emmanuelvalmas5648 i have the same station and you are right usually You want more airflow when you desolder and it depends what you desolder for example if you want to desolder a connector eg hdmi or a shield in mobile phone you can use 60 percent airflow
Hi Sorin. Could you explain what's the theory behind injecting 19Volts on the main power line input? Isn't it suppose to be too risky injecting anything above 1 or 1.5Volts?
Still don't understand why that resistor was causing the BQ chip not to send 25v to the gate of the FETs. As you said there must be some other circuit fed from that resistor that is controlling the BQ chip and preventing it turning on the FETs. Replacing the resistor with a link was enough to trigger it to work. Must be components changing value as they get older - drifting out of spec maybe.
Very odd. From what I could see there were two series resistors, one for each mosfet (PQ56 resistor shown at 6:59, PQ58 at 29:19). The schematics for various revs of this laptop suggest low values (0R, 2R2 etc) and although the BQ datasheet seems to omit them, it is good practice to include them (at higher values for various technical reasons). The original issue (BQ seems not to start properly) may still be there.
Great repair as always! Just one question: shouldn't the low side mosfet at charging circuit be shorted to ground to discharge the coil? Isn't it normal?