Thanks for a lot of interesting suggestions guys - all will get tried in part 2 ,which I will make tomorrow (3rd August) so you have all day today to put forward any other ideas you would like to see checked out. 🙂 I've added POLL to see what you guys think about this style of video. th-cam.com/users/LearnElectronicsRepaircommunity Please vote.
i definetely think injecting voltage is the best next step for diagnosing this laptop. Upon injecting the correct supply voltage at that coil, you would soon find out if the machine wants to turn on and work, or if that circuit pulls excessive current from your power supply triggering over current protection, in which case you would know the pch is defective and shorted
I had a similar situation the other day, where a lenovo had a shorted pch... and the pch didnt warm up much but it was pulling my 3v supply down.. so i injected voltage and found it drew over 5amps at 3v and the pch was burning hot
Hi Richard, I would suggest you measure the board while having the laptop lid open, hanging from the table as the hall sensor can have an impact on the power states.
Looks to me like you are on the right path. Can you operate the supply with that inductor removed to check the voltage or is that a buck or boost supply? I am not a laptop guy - I do mostly test equipment. Had to chuckle at the IR camera name "Hikvision". Regards, David.
Hi Richard, your coil PL5901 is for iGPU voltage, +VCC_GT and it is totally fine, its 0V ( even in good, working condition ). Your problem is most likely bad BIOS, which is very often case with this behaviour. Just flash another one.
Exactly. Altough this missing voltage is suspicious, maybe it's just not being initiated because of a BIOS issue? I would try and reprogram the BIOS chip. Also, have you checked the CMOS battery? I had a few laptops and desktop motherboards brought back to life just by replacing the battery...
@@rafak9177 He disconnected both battery and cmos battery in the video. Both I think he didn't hold down the power button after disconnecting to remove static charges, although the charges were probably gone while he went for lunch.
@@kriswillems5661 Not talking about resetting CMOS. Sometimes when you buy used/broken stuff, the battery is completely depleted and it needs at least 3V
I will tip on broken hall sensor, so power mode is suspend (fan running is weird) or corrupt bios in which case a reflash would do it...Cheers Richard !
I mostly repair laptops. In my experience after a lot diagnosis I'll found it's pch. Because it's getting bloody hot. Is this because of no cooling on pch? Ther is no thermal paste on any of them
Hi richard that is normal yhat coil has no voltage probably it is gfx coil . Which only comes up when it needed like by loading windows. To see the pch is good you can measure the datalines on usb they must be a in kiloohms. What i would suggest is try wit other ram. I dismantle board probably you have on underside soldered ram too. I also suggest to find the shematic with boardnumber. Because with model number you will not find it. But i think you are dealing with bad bios firmware. I will also suggest to look in that. Good luck regards Steve from Belgium
first disconect alll the conector (wifi card etc)... second try another ram, 3º read the voltage on bios chip pin 8, 1, 2, 3 and 5 ... 4º write another bios... 5º get the boardview and shematic if available 6º check the signais on super i/o, with lid on 7º check and measure the data line on usb ports to see if are shorted (shorted pch ) 8º lift up the coil withou voltage to see the voltage on mosfet for inject voltage, and see if heats very much but i think is the gpu coil that is only present on windows (after loading some grafics)... 9º reflow the ram chip joins ... 10º chek the cpu controller... 11º check all the coils with osciloscope... and measure others signais with that ... if nothing of this works i think that board or cpu is off ... greatings from Portugal ... ;)
I'm sure you have already checked the 'obvious' first. Check, disconnect, reconnect CMOS battery (stuck in a boot loop, reset BIOS). Fan looks badly blocked (but maybe trick of light or trick of dust).
Maybe inject power anyway just from zero and slowly ! we certainly could use a schematic and find out what that inductor is meant to be doing...cheers.
Heya oh yeah more interaction between you and you subscribers love it. I specaily like this video because I have a lenovo laptop i7 9 gen so probeble simmeler like this 1 so if I would get any problem....😉 I know something about it lol
Try another good ram maybe. Corrupted bios will show black screen with backlight. So i think it not bios problem. It can be a bad resistor which is in enable pin of ic pwm rail if there arent short coil to ground.
The WiFi card I can remove. And I guess webcam and other devices I can disconnect. Are you thinking the short is on the power rail that does not come up properly?
@@LearnElectronicsRepair I am not sure, but in that badcaps thread I referred to earlier, they were also talking about 1 power line not coming up - and there the missing power rail was related to the BIOS being corrupted.
PL5901 IS VCC_GT (ONE OF THE CPU/GPU SUPPLY) THIS PROBLEM MAINLY CAUSE BY STUCK BIOS, OR HALL SWITCH REPROGRAMING 16MB BIOS MOSTLY SOLVE THIS PROBLEM SOMETIME THIS PROBLEM ALSO CAUSE BY SIO SIO IS PROGRAMABLE 128KB KBBIOS IS INSIDE SIO SO IF YOU CHANGE SIO YOU ALSO NEED TO PROGRAM IT I HAVE SCHEMATIC, KB BIOS & MAIN BIOS FOR THIS BOARD OTHER POSSIBLITIES BIOS NOT GETTING 3V ONE OF THE ESD PROTECTION FAIL FAULTY KEYBOARD OR TOUCH PAD FAULTY SSD, HDD OR WIFI ANY STEP DOWN VOLTAGE MISSING
@@LearnElectronicsRepair no sir i am not shouting, i like the way you troubleshoot and thats the only reason why i reply. basically i never reply to anyone
Thanks for a lot of interesting suggestions guys - all will get tried in part 2 ,which I will make tomorrow (3rd August) so you have all day today to put forward any other ideas you would like to see checked out. 🙂 I've added POLL to see what you guys think about this style of video. th-cam.com/users/LearnElectronicsRepaircommunity Please vote.
I encountered the same problem with my laptop after a lightning storm fried it.
i definetely think injecting voltage is the best next step for diagnosing this laptop. Upon injecting the correct supply voltage at that coil, you would soon find out if the machine wants to turn on and work, or if that circuit pulls excessive current from your power supply triggering over current protection, in which case you would know the pch is defective and shorted
I had a similar situation the other day, where a lenovo had a shorted pch... and the pch didnt warm up much but it was pulling my 3v supply down.. so i injected voltage and found it drew over 5amps at 3v and the pch was burning hot
Hi Richard, I would suggest you measure the board while having the laptop lid open, hanging from the table as the hall sensor can have an impact on the power states.
Really?
@@LearnElectronicsRepair Yeah, Master Sorin made a video years back. th-cam.com/video/Fw0hA4RR2rU/w-d-xo.html
@@LearnElectronicsRepair Yep, I read that the lid switch/sensor can mess up your day.
Looks to me like you are on the right path. Can you operate the supply with that inductor removed to check the voltage or is that a buck or boost supply? I am not a laptop guy - I do mostly test equipment. Had to chuckle at the IR camera name "Hikvision". Regards, David.
There have been a couple suggestions of the same idea - so yes this test will definitely be made
Hi Richard, your coil PL5901 is for iGPU voltage, +VCC_GT and it is totally fine, its 0V ( even in good, working condition ). Your problem is most likely bad BIOS, which is very often case with this behaviour. Just flash another one.
i had same issue my client idapad s145.how can i flash the bios if the monitor wont displayed?
@@TravelAdventureetc You have to use some programmer. There is part two of this video, Richard is showing, how to do it.
Did you unplug the Bios battery first? make sure it's not a stuck Bios.
Hello Richard, Maybe a corrupter bios ? Grts
Exactly. Altough this missing voltage is suspicious, maybe it's just not being initiated because of a BIOS issue? I would try and reprogram the BIOS chip. Also, have you checked the CMOS battery? I had a few laptops and desktop motherboards brought back to life just by replacing the battery...
Yup corrupted BIOS is also my guess. Would remove the BIOS battery first.
@@rafak9177 He disconnected both battery and cmos battery in the video. Both I think he didn't hold down the power button after disconnecting to remove static charges, although the charges were probably gone while he went for lunch.
@@rafak9177 another way to remove static charges is shorting out the cmos battery pins with tweezers.
@@kriswillems5661 Not talking about resetting CMOS. Sometimes when you buy used/broken stuff, the battery is completely depleted and it needs at least 3V
Possibly bad super IO chip. I enjoy your videos. I am learning a lot from you.
That is true - how to prove it?
It was nice to see the bios update fixed the problem. I look forward to trying the same fix in the future.
Really nice video richard as always.
there are alot of good ideas in the comments(my guess is fried CPU/GPU or shorted PCI-E device)
I will tip on broken hall sensor, so power mode is suspend (fan running is weird) or corrupt bios in which case a reflash would do it...Cheers Richard !
Do a Sorin. Borrow the phase off another supply or use an MP1584 or something instead?
Have a go with your short finder to confirm if the short is on cpu and not elsewhere.
Good idea :D - A shameless plug for his short finder would be good 😆😋
I mostly repair laptops. In my experience after a lot diagnosis I'll found it's pch. Because it's getting bloody hot. Is this because of no cooling on pch? Ther is no thermal paste on any of them
Hi richard that is normal yhat coil has no voltage probably it is gfx coil . Which only comes up when it needed like by loading windows. To see the pch is good you can measure the datalines on usb they must be a in kiloohms. What i would suggest is try wit other ram. I dismantle board probably you have on underside soldered ram too. I also suggest to find the shematic with boardnumber. Because with model number you will not find it. But i think you are dealing with bad bios firmware. I will also suggest to look in that. Good luck regards Steve from Belgium
first disconect alll the conector (wifi card etc)... second try another ram, 3º read the voltage on bios chip pin 8, 1, 2, 3 and 5 ... 4º write another bios... 5º get the boardview and shematic if available 6º check the signais on super i/o, with lid on 7º check and measure the data line on usb ports to see if are shorted (shorted pch ) 8º lift up the coil withou voltage to see the voltage on mosfet for inject voltage, and see if heats very much but i think is the gpu coil that is only present on windows (after loading some grafics)... 9º reflow the ram chip joins ... 10º chek the cpu controller... 11º check all the coils with osciloscope... and measure others signais with that ... if nothing of this works i think that board or cpu is off ... greatings from Portugal ... ;)
try to remove the inductor and check voltages on the mosfet
my Money is on this comment :), this should give you the voltage range you need for injection
OK definitely I will check this. 🙂
Which one inductor you mean brother??
It can be the CPU connectors underneath which can be short circuiting with the pins making the conductor hot😁🤔
I think great big gold chain from the 80s will improve viewing numbers 👍
haha Medallion Man eh? Oh no sorry that was the 70s1
MUY BUENAS ESTA CLASE GRACIAS ES POSIBLE QUE ALLA PROBLEMA EN EL CPU
I'm sure you have already checked the 'obvious' first. Check, disconnect, reconnect CMOS battery (stuck in a boot loop, reset BIOS). Fan looks badly blocked (but maybe trick of light or trick of dust).
Sir, I want to ask... my Lenovo ideapad slim 3, the power light flashes continuously, I wonder what the problem is, what's in the BIOS...
Maybe inject power anyway just from zero and slowly ! we certainly could use a schematic and find out what that inductor is meant to be doing...cheers.
you need to setup a poll. INJECT voltage.. 100V 5A
I have no idea what's wrong, but I wish two things : that the bios is not involved nor any schematic used
Heya oh yeah more interaction between you and you subscribers love it. I specaily like this video because I have a lenovo laptop i7 9 gen so probeble simmeler like this 1 so if I would get any problem....😉 I know something about it lol
Richard this is completely off topic and I apologise but is there any chance you can do a video on vrm?
Like 'all you need to know about'... ?
Yeah that would be great 👍
Badcaps thread 89210 describes how to fix the problem by reflashing the bios
OK, that I can try - there have been a couple suggestions of the same
Why is my num lock button flashing but I can't power on the laptop
My same laptop blink 12 times what is problem
The solution is too simple, All you need to do is Flash the Bios and watch it come back to life. The Computer has no power issues.
OK I can give this a go in part 2
Check for 3.3v stdby for bios pin 8, 3.3v and 5v, then 1.8v and 1.5/1.35v for ram. Then 1 volt for cpu.
It looks like the RAM has 1.2V and the CPU (core) has around 0.75V-0.82V. I did find 3.3V and 5V on two buck regulators but I can check on the BIOS
Or you can check each one of power rail in a schematic if it exist.
Try another good ram maybe. Corrupted bios will show black screen with backlight. So i think it not bios problem. It can be a bad resistor which is in enable pin of ic pwm rail if there arent short coil to ground.
There night be a shorted USB or PCI bus device like an integrated webcam or maybe WIFI card.
The WiFi card I can remove. And I guess webcam and other devices I can disconnect. Are you thinking the short is on the power rail that does not come up properly?
@@LearnElectronicsRepair I am not sure, but in that badcaps thread I referred to earlier, they were also talking about 1 power line not coming up - and there the missing power rail was related to the BIOS being corrupted.
Coming issue with these. 3 and 5 v regulator
PL5901 IS VCC_GT (ONE OF THE CPU/GPU SUPPLY)
THIS PROBLEM MAINLY CAUSE BY STUCK BIOS, OR HALL SWITCH
REPROGRAMING 16MB BIOS MOSTLY SOLVE THIS PROBLEM
SOMETIME THIS PROBLEM ALSO CAUSE BY SIO
SIO IS PROGRAMABLE 128KB KBBIOS IS INSIDE SIO SO IF YOU CHANGE SIO YOU ALSO NEED TO PROGRAM IT
I HAVE SCHEMATIC, KB BIOS & MAIN BIOS FOR THIS BOARD
OTHER POSSIBLITIES
BIOS NOT GETTING 3V
ONE OF THE ESD PROTECTION FAIL
FAULTY KEYBOARD OR TOUCH PAD
FAULTY SSD, HDD OR WIFI
ANY STEP DOWN VOLTAGE MISSING
@Jay Vyas There is no need to shout here to be heard 😉
@@LearnElectronicsRepair no sir i am not shouting, i like the way you troubleshoot and thats the only reason why i reply. basically i never reply to anyone
Shouting in internet slang means typing all capital letters.
@@kriswillems5661 ohhh sorry my bad, I thought shouting means unnecessary writing 😅
Cool...Interesting...
Thanks for posting this is such a cool video!
Watch this video: FIX Lenovo Laptop HAS POWER but NO DISPLAY/BLACK SCREEN after switching from EUFI to LEGACY on BIOS...
Usb port shorted
I can check that
Backlight.
I can try disconnect the LVDS cable (can't see any others going to the screen but will check)
bios .......
Send it off to northridgefix 😂