• Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start

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#1 Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 11 Oktober 2018, 18:51
Hi ,
when i plug AC ,
power light and battery led comes and stay
when i press power button nothing changes no fan no display .
i have check voltage:
PL101=9v
PL201=0v
PL202=0v
PL301=0v
PL401=0v
PL801=0v

this motherboard doesn't have Nvidia chipset

Best regards

Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a Google Adsense [BOT] 11 Oktober 2018, 18:51

#2 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 11 Oktober 2018, 20:35
Hello!

Measure the voltages to ground on pins 2, 12, 14, 74, 108, 128 of KBC chip.

Measure the voltages to ground on pins 76, 86, 109, 110 of KBC chip in the following cases:
a) Power button released.
b) Power button pressed.

#3 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 12 Oktober 2018, 16:23
Hi,
here's voltage

pin 2= 0.08v
pin 12= 0v
pin 14= 0v
pin 74= 0v
pin 108= 0v
pin 128= 0.02v

power bouton on
pin 76= 0.18
pin 86= 0.31v
pin 109= 3.37v
pin 110=0v

power button Off
pin 76=0.37v
pin 86= 0.31v
pin 109= 3.37v
pin 110= 3,37v

Best regards

#4 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 14 Oktober 2018, 17:33
Measure the voltages to ground on coils PL201 and PL202.

Measure the voltages to ground on pins 1, 5, 8 of PU201.
Measure the voltages to ground on pins 1, 7, 8 of PU202.

PU201 and PU202 pincount (top view):
Slika

#5 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 14 Oktober 2018, 19:33
Hi,
here's voltage

PL 201 = 3,4v
PL 202 = 0v

PU 201
pin 1 = 3,4v
pin 5 = 3,4v
pin 8 = 9,03v

PU 202
pin 1 = 0V
pin 7 = 5,2v
pin 8 = 9,03v
So i checked pin 123 of EC there's 0v .
KBC is defect ?

Best regards

#6 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 14 Oktober 2018, 20:14
sebuncle napisal/-a:KBC is defect ?
Probably no.

It seems there is too low voltage on main power rail "B+".

Measure the voltages to ground on pins 1, 4, 5, 6, 8, 9, 12, 16, 17, 20 of charger chip PU101.

Was this laptop spilled?

#7 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 15 Oktober 2018, 01:10
Hi ,
matic napisal/-a:
It seems there is too low voltage on main power rail "B+".

Measure the voltages to ground on pins 1, 4, 5, 6, 8, 9, 12, 16, 17, 20 of charger chip PU101.

pin 1= 21v
pin 4= 26,8v
pin 5= 3,3v
pin 6= 2,8v
pin 8 = 0v
pin 9 = 0v
pin 12= 9,03v
pin 16 = 6v
Pin 17 = 15,4v
pin 20 = 20,8v

matic napisal/-a:Was this laptop spilled?

i don't know , the seller has not given any information

Best regards

#8 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a Machine 15 Oktober 2018, 13:36
Measure the voltages on pins 18, 21, 26, 86, 93, 106, 108, 123, 124 of KBC.
Measure the voltages on pin 110 of the KBC in the following cases:
at the power off
with pressed power on
to the power on.

#9 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 15 Oktober 2018, 15:35
Hi
Machine napisal/-a:Measure the voltages on pins 18, 21, 26, 86, 93, 106, 108, 123, 124 of KBC.

i checked , all voltages have 0v

Machine napisal/-a:Measure the voltages on pin 110 of the KBC in the following cases:
at the power off
with pressed power on
to the power on.

At the power off without press power there's 3.3v (battery and power leds are already on)
i press power button there's 0v , when i release voltage go to 3.3v

For these tests the battery is not connected

Best regards

#10 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 15 Oktober 2018, 21:04
Measure the voltage to ground on both pins of highlighted resistor (picture below).

Slika

#12 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 16 Oktober 2018, 19:08
Hi
this resistance is missing :shock: I have 3.4v on one point
What is her value ?
Best regards

Slika

Slika

#13 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 16 Oktober 2018, 19:21
sebuncle napisal/-a:What is her value ?
The value of this resistor is 0Ω, package 0603 (jumper resistor).

#14 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 16 Oktober 2018, 20:29
I put this resistance and now:
-no lights when i plug AC
-on the resistance the voltage has dropped to 0,4v

There's a short on this line ?

Best regards

#15 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 16 Oktober 2018, 20:33
Yes, there is a short circuit to ground.

I'm 99% sure that tke KBC chip is bad. You could perform a short circuit test to be 100% sure or just remove the KBC chip and check the resistance to ground again.

#16 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 17 Oktober 2018, 20:11
matic napisal/-a:Yes, there is a short circuit to ground.

I'm 99% sure that tke KBC chip is bad. You could perform a short circuit test to be 100% sure or just remove the KBC chip and check the resistance to ground again.

Hi ,
you are right .
I unsoldered the kbc and after there's no short.
I'll try to put a new a i'll tell you.

Machine and Matic thank a lot for your help
Best regards

#17 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 17 Oktober 2018, 20:16
By the way, that KBC chip requires programming, so you have to flash it after the exchange.

#18 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 20 Oktober 2018, 15:23
Hi
matic napisal/-a:By the way, that KBC chip requires programming, so you have to flash it after the exchange.

oK i wait for a new.
Best regards

#19 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a sebuncle 2 November 2018, 22:01
Hi
I soldered the new , i have only 0.8v on the resistance .
Resistance with ground is 1MΩ.

Best regards

#20 Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a matic 3 November 2018, 13:37
Repeat the measurements suggested in the post #4 - ***click***

Re: Lenovo yoga 3 14 /80JH/BTUU1 NM-A381/ doesn't start


Napisal/-a Google Adsense [BOT] 3 November 2018, 13:37

Kdo je na strani

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