Part number : NM-B901
Fault: Dim display.

This Lenovo T490 was brought in for dim display fault, the lvds 19v fuse was short, just remove and put a jumper and display is back to normal.

This is one of the reasons I like Lenovo boards, unlike some other brands, there's no fuse break the circuit in case of over current, which will help protect the screen.

I worked on an ACER mobo, there's no fuse to break the over current on the lvds section from getting to the screen, even though the fuse on the screen was short,it ended up damaging the screen back light.
Trying to work another backlight by using another screen panel is another work on it own entirely.

The thing,if there's a fuse on the board to do this job,it will protect the screen or signal cable from getting damage.

Good day, my hp cs0053cl laptop shows charging without a corresponding increase in battery level. What could be the cause? Someone said its the charging IC on the motherboard. I bought it brand-new two years ago

fiyahe:
Good day, my hp cs0053cl laptop shows charging without a corresponding increase in battery level. What could be the cause? Someone said its the charging IC on the motherboard. I bought it brand-new two years ago

Yeah it's easy to just tag the culprit as charging ic because of the name charging but it takes other section to enable your laptop to charge.

It's a game of voltage and current,a slight change in voltage or current will affect charging.
Starting from the VIN section where you connect your charger, down to the discharging MOSFET, charging MOSFET , boosting diode, boosting capacitor,to the SIO chip, battery and the charging ic itself.

What I'm trying to say is that one have to diagnose it and get where the fault is before concluding.

Udemzy05:


Yeah it's easy to just tag the culprit as charging ic because of the name charging but it takes other section to enable your laptop to charge.

It's a game of voltage and current,a slight change in voltage or current will affect charging.
Starting from the VIN section where you connect your charger, down to the discharging MOSFET, charging MOSFET , boosting diode, boosting capacitor,to the SIO chip, battery and the charging ic itself.

What I'm trying to say is that one have to diagnose it and get where the fault is before concluding.

Ok. Whats the cost of getting a new motherboard? Can i have ur contact details?

fiyahe:


Ok. Whats the cost of getting a new motherboard? Can i have ur contact details?

08064724259

Goodevening Engr,

My laptop just suddenly shut down while in use, although I was feeling sleepy while using it, so during that period when the laptop wants to 'sleep' because of inactivity, I will touch any key and it will pick up again. I did this twice before it finally tripped off and didn't come up again. Then sleep cleared from my eyes.

However, about a night before that night that the laptop tripped off, I unknowingly forgot the laptop on charge throughout the night but in the morning I disconnected it and it worked fine until that fateful night. Now I don't know if leaving the laptop throughout the night caused the laptop to shut down and won't come up or if it was the regular 'waking it up when it wanted to 'sleep' that caused it.

I took it to a repairer but after testing all those components(capacitors, resistors etc) he said 'they all are bringing light' but still the laptop is not turning on. I remembered he said he can't test the other chips/ic, because they have many pins. Then he concluded by saying that if the fault is from the chips, there is no how he can diagnose the fault.

I observed that he is an amateur, so I asked around and was referred to a 'professional', I told him how the fault happened and he immediately said it is the power IC and asked me to come back and carry the laptop later. But when I came back, he said that he has checked it, that its indeed the power IC but that I have to exercise more patience as he doesn't have the power IC for the laptop in his shop and that its not something that can just be bought from the market and he can't use anyone as they won't be same voltage. That he will need to go and find the scrap of my laptop to take the power IC and fix in mine or the scrap of a recent model laptop. I agreed because people around attested to his capacity.

But now I am thinking if he even opened my laptop because he was too busy since the time I gave him my laptop till I came back. If his mind just told him that it must be power IC or if he said it base on experience.

Please Sir, from what I explained, what could be the problem. The laptop is a Hp Probook 450 G4.

I am just waiting still on Tuesday that he asked me to come. I just hope it would be fixed but I am so anxious...

Part number : 6050a2728501
Fault: Dead ( no power)

The engr brought this case for repair, this is a typical fault of most HP elite book , this then to happen a lot on folio 9470,9480, 840 G1, 840 G2 ,840 G3 and even zbook because some zbook share the same motherboard with 840, though they come with graphic chip.

The motherboard doesn't power on but when the CMOS battery is removed and charger is plugged in, it powers on and shutdown after 2-4 secs.

Base on experience, since there's no schematic for this model yet.
The power button voltage was reading 0.750v which is abnormal,it should be 3.3v.
Check the picture to get the trick.

Mobo works fine after that.

Part number: 6050a2637901
Fault: Dead.

This is a typical fault of this laptop, especially on the elite book models.
Mobo is completely dead but when CMOS battery is removed and charger is connected it will power on and shutdown, when power button is triggered,it won't power on until you remove the charger and connect it back.

I've posted a lot of similar cases here,just remove and replace with 1k ohms resistor and mobo is back to life.

Power button voltage drops to 1.9v which is not enough to trigger the switch.

[quote author=udemzyudex post=105505223]

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 [/quot]

Bros I want 2 learn work.. Where is your location?

I noticed the anti spam bot always ban me for using a certain word,I've been banned severally whenever I post that kind of issue here,so I'll omit the word in any of my post.

Part number: 6050a2560201
Fault : shutdown after 5sec

This mobo was brought in for repair, according to the engr it powers on but does not display to screen.
.I believe he must have done his own troubleshooting before concluding,so I didn't bother to test it.

I reprogram the BIOS chip but problem persist, after checking,I noticed it powers on and shutdown after some seconds.
Voltages were available on the coils, there's no short and processor was getting a little heat.

I check the DC to DC section and notice voltage on source of Q7151 was missing,I run a jumper wire from pin 1 to pin 4 to force switch the voltage.

After this ,processor was heating and mobo display fine.

Part number : 6050A2514101
Fault : Plugin not charging

This folio 9470m came in with not charging issue,I check the ACFET, RBFET, discharging MOSFET and charging MOSFET to be sure there's no short.

Move on to the charging IC.
Vcc 19v
Acdet : 5v
Acok : 3.3v

Without going further I could see where the fault is, ACDET was getting 5v instead of 2.6v, the maximum it should get according to the datasheet is 3v.

The voltage divider circuit was faulty, I replaced the R6021 and R6023 and ACDET got back to 2.6v and mobo charge fine.

The importance of checking CLR communication with charging IC.

I have a plugin charging but percentage not increasing case , the client said he already use another new battery but it still didn't increase.

After taking out the mobo, I check for short on VIN section and it was fine, discharging MOSFET was also fine too.

Unfortunately CLR communication was bad, pin 2 of charging IC was not communicating, trace back and notice a damage track,I try to build the track but it was too tiny and I don't have a trinocular.

I run a jumper on the line and check for continuity and communication was fine,after that mobo works fine.

Part number: 6050A2648201
Fault : No display

After doing all the necessary basic things,I noticed vcore voltage was missing.
I check the vcore section and notice some abnormalities on the pins.

Pin 3 = 2.5v
Pin 4 = 2.6v
Pin 5 = 0v
There should be 1.05v on these pins, I check the impedance and it was fine, I replace the IC and mobo works fine.

udemzyudex:
Most times client do call and require for the amount it will cost to fix a laptop power IC,

Hi...pls I have this elitebook 8540p laptop that refuse to turn on and when plugged in the charging Indicator only blinks for a sec(from orange to green).........sometimes it comes on after abandoning it for awhile, it'd work for some days then the problem resurface again....pls what's the issue

vichaz10:


Hi...pls I have this elitebook 8540p laptop that refuse to turn on and when plugged in the charging Indicator only blinks for a sec(from orange to green).........sometimes it comes on after abandoning it for awhile, it'd work for some days then the problem resurface again....pls what's the issue

Remove the battery, open the back and unplug the CMOS battery, then connect your charger and see if it will come up.

udemzyudex:


Remove the battery, open the back and unplug the CMOS battery, then connect your charger and see if it will come up.

Did this awhile back and it's still doesn't work

vichaz10:


Did this awhile back and it's still doesn't work

If you're in lag,you can reach me on 08064824259

Part number : NM-A091

Fault: HDD not detected.

Two if this Lenovo laptop was brought in for repair,the engr said it doesn't detect HDD,I powered it on and got the HDD detection error.

He said it is a BIOS issue,I flashed a new bios file but problem persist, I check the transmitting and receiving lines if any of the capacitor is short to ground but they were ok,same with the VCC line.

Connect the charger, power it on and checked the vcc line and noticed there was no voltage on the line, traced back to the fuse and found out that voltage was available at pin 2 of F1 which means the fuse is faulty.

I removed it and run a jumper and VCC5B was available on pin 7 of J1 connector.
Now,I connect the HDD and power it on,board now run fine.

Udeme

I don't know if its ok for an engineer to seek help from you through here

The issues has explain by the owner says system was working perfectly fine until it short down automatically. With battery it shows de power indicator light and even after removing of ba3 plugging direct still show's a steady white light and still not power on

When brought i checked the processor and everything works fine but repeat after a day or two of usage

Am asking to know if you have come across such issues, mobo won't boot on this issues and i seek a steady fix

System is hp

[color=#990000][/color] system is HP 550

udemzyudex:


Remove the battery, open the back and unplug the CMOS battery, then connect your charger and see if it will come up.

please help me out on your suggestions

Your distance is far would have brought it to you

Samfilo31:
[color=#990000][/color] system is HP 550 please help me out on your suggestions

Your distance is far would have brought it to you

Does it power on when the power button is triggered?

If yes check if voltages are available on the coils.

Thanks for the response
The problem is that immediately you insert ba3 or plug in charger it indicate light

udemzyudex:


Does it power on when the power button is triggered?

If yes check if voltages are available on the coils.

it doesn't even boot at all

Samfilo31:
Thanks for the response
The problem is that immediately you insert ba3 or plug in charger it indicate light it doesn't even boot at all

The basic thing you can do now is just probably service the board ( wash and sun dry it) since you've done some necessary things already.

If you're a chip level technician i can give more suggestions.

Udemzy05:
The importance of checking CLR communication with charging IC.

I have a plugin charging but percentage not increasing case , the client said he already use another new battery but it still didn't increase.

After taking out the mobo, I check for short on VIN section and it was fine, discharging MOSFET was also fine too.

Unfortunately CLR communication was bad, pin 2 of charging IC was not communicating, trace back and notice a damage track,I try to build the track but it was too tiny and I don't have a trinocular.

I run a jumper on the line and check for continuity and communication was fine,after that mobo works fine.

engineer on the chip level. i want to ask a question ?. running these jumper stuffs, is it like a way of bypassing something or a shortcut Way to something instead of going the normal route to achieve same results

Adewale1603:
engineer on the chip level. i want to ask a question ?. running these jumper stuffs, is it like a way of bypassing something or a shortcut Way to something instead of going the normal route to achieve same results

Yeah,it can either be just using lead to connect two point or running an insulated wire from one point to another.

If you check the laptop motherboard you will see line traces,this carries data/voltage from one points to another,a component or line at the top might be supplying data/voltage to another point at the bottom,and sometimes track might be damage and the only way to pass this voltage/data across is through a jumper.

Another scenario is Fuse ( another point is understanding the basic electronic components,it uses and function) if a fuse is open I can easily remove it and put a soldering lead as a jumper because I understand that even if it is not there it won't amper the performance of the board.

Unlike replacing a MOSFET with a diode which difference is just switching.

Hello Engineer, kindly send your address to me, I have a job which I'd like you to help me with

You can also, just leave your number here for me to call you and discuss it before I come