udemzyudex, will help you. an engineer on the board and chip level

Nerdnextdoor:
Hi guys. I connected, my Lenovo IdeaPad 310-15isk core i5, to a wrong power charger and now it won't come up when plugged to the right charger and No charging led is showing. Please what can the problem be? My repair guy seems not to know much about this problem.

A lot of things can occur, either a shorted cirrucit because there's always a protection cirrucit on the motherboard, a bad charging ic, power ic or shorted sio.

If your in lag, you can reach me on 08064724259,I'll fix it for you.

Adewale1603:
udemzyudex, will help you. an engineer on the board and chip level

Thanks for the mention.

One of the advantages of schematic reading is that you can easily assist someone who is not even close to you.
A colleague was having a hard time trying to figure out why the DC to DC section of the mobo he was working on was not switching, this particular mobo uses a different type of switching process.

It makes use of boosting caps, what this does is to increase the voltage to a higher volt just like amplifier.
From 5v to 10v from 10v to 15v with the help of a diode.

I told him to check the boosting caps since he was getting a low volt instead of high voltage, the issue was resolved by just fixing one boosting capacitor because it was missing on the mobo probably due to handling.

Mobo works perfectly now.

Part number : LA-9104P

Fault : No power

Diagnosis: first thing first, check the impedance of all coils and CLR, I noticed there is a partial short in the VIN line.

This type of fault can be very difficult to trace if you don't know how to handle it, board was returned from another engr and i could see some trace of work done.

CLR impedance was reading 0.184 instead of 0.400 or more.

The culprit was removed and mobo works fine.

Part number : DAQT6AMB8F0

Fault : No power

Typical fault in this models, dv5, dv 5000, dv6000

5v/3.3v available but rsmrst# was missing on SIO chip.
Reprogrammed the bios and mobo works fine.

Please my Dell precision m4600 while using, there was a fluctuation in power supply suddenly tripped off and has not come on since. When I plug the charger to a power source, the LED comes on, but when once I plug the charger to the laptop, it goes off,

Please I need help, when I plug in my laptop charger, the laptop LED power indicator will blinks like 3 times then stop, it won't charge, and the laptop battery is totally dead, but charger is not charging it neither is the system connected to power.

Laptop brand is HP.

Core i5 vpro

Window 7

3rd generation.

Please what could be the cause.

Fixed. Thanks, Udeme.

Nerdnextdoor:
Hi guys. I connected, my Lenovo IdeaPad 310-15isk core i5, to a wrong power charger and now it won't come up when plugged to the right charger and No charging led is showing. Please what can the problem be? My repair guy seems not to know much about this problem.

pman096:
Please my Dell precision m4600 while using, there was a fluctuation in power supply suddenly tripped off and has not come on since. When I plug the charger to a power source, the LED comes on, but when once I plug the charger to the laptop, it goes off,

There is a short circuit on your laptop, I can fix it for you if you're in lag.

askaz:
Please I need help, when I plug in my laptop charger, the laptop LED power indicator will blinks like 3 times then stop, it won't charge, and the laptop battery is totally dead, but charger is not charging it neither is the system connected to power.

Laptop brand is HP.

Core i5 vpro

Window 7

3rd generation.

Please what could be the cause.

Looks like a hp ProBook or elitebook, there is a short circuit on your motherboard, if you're in lag I can fix it for you.

It's a motherboard issue.

Hp ProBook

Fault : charging indicator keeps blinking, and doesn't power on.

I found out there is a short circuit on the mobo that leads to burnt component that also affect the pcb in the process.

Especially ProBook laptops of 2nd and 3rd gen, the pcb is fragile, when you noticed the laptop is not turning on and the charging light keeps blinking, just remove the battery and don't Plugin in the charger till you see a technician else you will end up damaging the mobo beyond repair.


The VIN mosfet and discharging mosfet were completely burnt, it affected the mobo in the process.

I removed the burnt mosfet, clear the part of the VIN mosfet and discharging mosfet.
Check the impedance of CLR there was still short, so I inject volt and find out one N-channel mosfet in the vrm section was getting hot.
I removed and replace it and short was gone.

The burnt vin mosfet is a p-channel so I jumper it with a lead since tracks were completely burnt and I can't replace the mosfet.


Mobo powers on and works fine now.

udemzyudex:


Looks like a hp ProBook or elitebook, there is a short circuit on your motherboard, if you're in lag I can fix it for you.

It's a motherboard issue.

likely elitebook. all these vpro technology

udemzyudex:
Hp ProBook

Fault : charging indicator keeps blinking, and doesn't power on.

I found out there is a short circuit on the mobo that leads to burnt component that also affect the pcb in the process.

Especially ProBook laptops of 2nd and 3rd gen, the pcb is fragile, when you noticed the laptop is not turning on and the charging light keeps blinking, just remove the battery and don't Plugin in the charger till you see a technician else you will end up damaging the mobo beyond repair.


The VIN mosfet and discharging mosfet were completely burnt, it affected the mobo in the process.

I removed the burnt mosfet, clear the part of the VIN mosfet and discharging mosfet.
Check the impedance of CLR there was still short, so I inject volt and find out one N-channel mosfet in the vrm section was getting hot.
I removed and replace it and short was gone.

The burnt vin mosfet is a p-channel so I jumper it with a lead since tracks were completely burnt and I can't replace the mosfet.


Mobo powers on and works fine now.

but these tasks require soldering works.

Adewale1603:
but these tasks require soldering works.

Exactly.

udemzyudex:


Exactly.

like heating the ics, to soften them and removing the chips, circuits, and resoldering them back

Adewale1603:
like heating the ics, to soften them and removing the chips, circuits, and resoldering them back

Tonl easily remove and place back smd component, you need rework station, soldering paste and twizzer.

Hp Pavilion dv7

Fault : No power


The transistor got burnt, so voltage was not switching properly from drain to source to generate 19v to the mobo despite the 28v on gate.


I run a jumper of 19v close to the battery to the source of the transistor, and 19v was pressent on mobo, then I power it on and laptop works fine.

Elitebook 840 G1/G2 bios password removed.

Easy and fast.

Hp 15 with part number LA-D702P

Fault :
Comes in as powered on but doesn't display.

Diagnosis

Check impedance on all coils for short, then power on the mobo to see if volt is available on all coils, check dc/dc section too, everything was fine and dc reading gives a clue.

Reprogram the bios and mobo works fine.

Check display via external keyboard and caplock/numlock is working fine.

Hp folio 9470

Fault : dead, no power.

The charging indicator keeps blinking red/white when you connect the charger, it doesn't power on when the power button is press.


First thing first, check the impedance of all coils and i noticed a short on the 5v coil, its time to check if it is an input short or output short.

The input is the power ic while the output is where the 5v goes to, the 5v goes to your USB ports, hdd, 5v dc/dc mosfet etc.

I have to isolate the input and output to identify where the short is, after that I noticed fault is coming from the output section of 5v, the best thing to do is to inject volt to the output section to flush out the culprit.

After that I noticed, the 5v caps of USB port was heating up, I removed and replace it and the short was clear.

Connect back the isolated point and check the impedance again, the 5v coil was good, connected the charger and mobo works fine.

LENOVO ideapad 330 with part number nm-b451

Fault : No power


Diagnosis : VIN line short.

Measured the impedance of CLR and it was 0.004,inject volt and the culprit was found.

Removed and replaced the caps, board works fine.

Elitebook 8460p


Fault : No power

Diagnosis : first thing first, check the impedance of all coils and CLR.

VIN line is short to ground, I followed the normal procedure and mobo is back to life.

Hp spectre x360 with part number DA0Y0DMBAF0

Fault ; No power

Diagnosis : According to the engr, it suddenly went off when the owner was using it.

It looks like it has been worked on before because I could see some missing 19v caps ,well first thing first.

Impedance on all coils is good
No liquid damage
No burnt

Long story short, VIN mosfet was short, replaced the mosfet and mobo works fine.

udemzyudex:


Chai, there's a possibility that the bios is corrupt or the operating system.

I always advise users to plug in charger when resetting, updating or formating their laptop.

If you're in lag I can help you fix it.
08064724259

i sincerely wish I saw this thread earlier, I had a dell once I power it on, it displays d dell icon then shut down, at a point is it stopped coming up. All effort by my engineer proved abortive, had to let go of the system

rerhji:
i sincerely wish I saw this thread earlier, I had a dell once I power it on, it displays d dell icon then shut down, at a point is it stopped coming up. All effort by my engineer proved abortive, had to let go of the system

Sorry about that.

Dell inspiron 1525

Fault : Dim display

Diagnosis :
According to the engr, he tried another module and screen but problem persist

From experience, most of the time, dim display issue is always cause by missing 19v to the screen, I check the 19v fuse close to the screen connector and notice it was open, the 19v wasn't crossing over to the module.

I removed and jumper it with lead and 19v line is OK, and yet the dim display is still there, then there is a 100% chance that the module is bad is 19v is present now.
I replace the module and laptop works fine.

udemzyudex:
Dell inspiron 1525

Fault : Dim display

Diagnosis :
According to the engr, he tried another module and screen but problem persist

From experience, most of the time, dim display issue is always cause by missing 19v to the screen, I check the 19v fuse close to the screen connector and notice it was open, the 19v wasn't crossing over to the module.

I removed and jumper it with lead and 19v line is OK, and yet the dim display is still there, then there is a 100% chance that the module is bad is 19v is present now.
I replace the module and laptop works fine.

Omo x1000. experience is the best teacher

Adewale1603:
Omo x1000. experience is the best teacher

Yeah experience will make you go to the exact place you need to check, more like a testing point before any other check if problem doesn't come from where you expected.

Folio 9470

Fault : No power

First thing first, I checked the impedance of all coils for any short to ground.

I noticed the 5v standby regulator coil was short to ground, since this is another typical fault on this motherboard, I went straight to the culprit and removed it.

The 5v USB capacitor was removed and replaced.
I checked the impedance again and it was fine, connect the charger and boom, mobo works fine.

Engineer Udem, please help me out here .My Acer travelmate won't turn on . I was gaming one evening like that and Nepa ceased power, but I continued. After some time the system froze, I waited for minutes so I had to force shut it by holding down the power button. It did shutdown, but the orange battery Indicator light kept blinking for days, till the battery drained out. Nepa finally restored power and it charged really fine, (battery Indicator working perfectly). However the mobo has refused to turn on since then. I noticed in the dark, whenever I open the lid or push the power button, the power and battery Indicators (orange and blue light) flashes in a millisecond and goes off, it's almost unnoticeable.
Also when I hold( ESC+Fn+POWER ) BIOS) the power Indicator(blue light) starts blinking every two seconds continuously. But it still doesn't turn on.
What marvels me, Is that the sleep charge USB port still functions flawlessly, it still charges my phone.It's a non removable battery, so I googled and I've done the pinhole battery reset and power button stuff to discharge static electricity but to no avail. I even had to find a way to detach the battery to power it on through the PSU. But the milliseconds stuff is all I get.