HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on

Hey there...

My problem is as described in title...

I've got no DC jack light, when charger is plugged in. After presing power button the DC jack LED blinks 3 times and that's it.

So measured PU2 & PIN6 (ACDET) is only 2.7V...All other voltages on PU2 seems to be OK...
Voltage on PR55 is 19V on one side & 2.7V on the other one...

PU2 (BQ24728) voltages:

PIN1=19V
PIN2=19V
PIN3=19V
PIN4=25V
PIN5=3V
PIN6=2.7V???
PIN7=0V???
PIN8=3.3V
PIN9=3.3V
PIN10=3.3V
PIN11=2.8V
PIN12=2.8V
PIN13=2.8V
PIN14=0V (obviously AS GROUND)
PIN15=0V
PIN16=6V
PIN17=6V
PIN18=2.7V
PIN19=2.7V
PIN20=19V

Also tried to re-flash BIOS SPI & replaced PQ16 & PQ17...

Any help would be appreciated...Thanks

Hello!

All the voltages on charger chip are ok.
2.7V on pin 6 is correct value.

Measure the voltage to ground on pin 71 of KBC chip (U14).

matic wrote:Hello!

All the voltages on charger chip are ok.
2.7V on pin 6 is correct value.

Measure the voltage to ground on pin 71 of KBC chip (U14).

Thanks for your reply...

I thought the ACDET voltage is not correct as I couldn't find BQ24728 datasheet anywhere.

KBC Voltages:

PIN71=0.8V???
PIN11=1.8V???
PIN74=3.3V
PIN127=3.3V
PIN26=3.3V(assume all other VSTBY have correct voltage)

Now...I think my problem is with VCC on KBC (PIN11)...There must be something pulling down the voltage on +3V rail...Resistance on PIN11 is about 114KΩ

Measure voltage on both pins R293.

0.8V on pin 71 of KBC chip is correct value.

loser18 wrote:Now...I think my problem is with VCC on KBC (PIN11)...There must be something pulling down the voltage on +3V rail...Resistance on PIN11 is about 114KΩ

"+3V" is a suspend power rail, where the voltage should appears after pressing to the power button.

Measure the voltage to ground on pin 12 of KBC chip.
Measure the voltages to ground on coils PL21 and PL22.
Measure the voltages to ground on pins 2 and 3 of PU6 before and after pressing to the power button.

I was giving you wrong voltage of PIN 11 on KBC...I was reading PIN12 instead...Just checked it under microscope...Really sorry about that...

KBC:

PIN11=0V
PIN12=1.8V

PU6:

PIN2=0V
PIN3=0V

Both before & after pressing power button

PL21=0V
PL22=0V

Measure the voltages to ground on pins 35, 120, 123 of KBC chip in the following cases:
a) Before pressing to the power button.
b) After pressing to the power button.

Measure the voltages to ground on pins 79, 125 of KBC chip in the following cases:
c) Power button released.
d) Power button pressed.

matic wrote:Measure the voltages to ground on pins 35, 120, 123 of KBC chip in the following cases:
a) Before pressing to the power button.
b) After pressing to the power button.

Measure the voltages to ground on pins 79, 125 of KBC chip in the following cases:
c) Power button released.
d) Power button pressed.

PIN35=0V
PIN120=0V
PIN123=0V

PIN79=0V
PIN125=3.3V & goes low when power button pressed

Replace the bios and remember to save the old one.
If it does not fix replace the KBC.

Machine wrote:Replace the bios and remember to save the old one.
If it does not fix replace the KBC.

I've re-flashed & even replaced SPI twice...

Replace the KBC chip.

OK...

So I've phoned my customer to ask him how did this happen. He said it was caused by faulty adapter (broken cable). I've immediately checked AD_ID & it reads only 1V...Also EC8 was blown, but it's been replaced...Does anyone know if the 1V on AD_ID is correct voltage before I'll replace KBC? I think it should be around 7-8 volts...

Correct voltage value on line "AD_TYPE" (pin 71 of KBC chip) is around 0.75V with 90W power adapter.

Check this components:

OK guys...

It's been a long time. The laptop is fixed now. I've replaced KBC & everything is working as it should be, however I've had some problems, which I'll explain below.

#1 Heads up:

My original KBC / IO chip was IT8528E EXS . I've ordered AXS & after replacement laptop was completely dead (not even 3 blinks on charging LED). I was never ever thinking the last 3 digits/numbers would make any difference (datasheet also describe them only as a "TRACKING CODE") but after digging some forums I've found out it's actually firmware number as well. Ordered IT8528E EXS & laptop seemed to be completely fixed. So just to let you know, next time you'll be replacing IT8528E or any IT KBC, buy the same "TRACKING CODE"

#2 Heads up:

After the KBC replacement & windows installation everything was working OK except battery charging. When I've started it, BIOS reported straight away the battery needs to be replaced,press enter, blah blah. First I thought my soldering job with KBC was not 100% & MBCLK data is not communicating properly (because I knew battery is OK), however that was not the case. The problem was I've tried another BIOS dumps, but once It's been re-flashed back to my original dump, battery is charging & also reporting OK. So just to let you know again, use your own dump if possible or it may be dependant on DMI information. Not sure.



Anyway...Thanks for all of your help mates...I hope this info will help....