Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
OK...
So I've replaced CPU & laptop finally started charging, but still didn't want to turn on.
Re-checked KBC main voltages & they were exactly the same.
After replacing KBC the laptop seems to be fully working now.
Thanks to everyone for help...
loser18
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Last Activity: 06-05-2020, 08:07 AM
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
Actually it's PIN75 (at least on my shcematic) and I have 3.3V there.
Just noticed that AC_PRESENT signal on PIN112 fluctuates.
My gut tells me the KBC will be faulty....Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
As I can see Redwood got different power sequence... Even KBC is connected different way...maybe I was looking on completely wrong schematic...now I'm confused,LOL...Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
I see now...
I should have been clearer. I'm using cedar for KBC circuit only. For charging and 3V & 5V circuit I'm using wistron Hadley 14 schematic.I'm pretty sure that BQ and TPS voltages are OK.Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
Well I'm using Wistron Cedar as a reference. I Couldn't also find Q2402 on mobo ( it's marked as Q2404 on Redwood schematic), but thought it will be similar architecture. Even most of the components marking numbers are right with my one. It's really hard without schematic.
About the AC_IN# signal, it should be active low? Why are you confused about that?...Last edited by loser18; 01-05-2019, 07:38 PM.Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
Does anyone know what signals must be present on NPCE285 before it sends PSL_OUT# ?Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
PSL_IN1# = AC_IN# on PIN74 is low (0V)
AC_IN_KBC# is also lowLast edited by loser18; 01-05-2019, 02:55 PM.Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
OK...So, I have replaced BQ24715 because those readings were wrong. New voltages:
1=20V
2=20V
3=20V
4=25V
5=3V
6=2.6V
7=0V
8=0V
9=0V
10=1.4
11=9V
12=9V
13=9V
14=0V
15=0V
16=6V
17=13V
18=9V
19=9V
20=19V
All measurement done with battery connected.
I think the problem is motherboard doesn't enter into S5 state as I've missing 3D3V_AUX_KBC...Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
So I've replaced PU4402 & now the board is dead.
PU4402 Voltages:
PIN 1= 0V
PIN 2= 1.9V
PIN 3= 2.9V
PIN 4= 0V
PIN 5= 0V
PIN 6= 0.9V
PIN 7= 0V
PIN 8= 0V
BQ24715 Voltages:
PIN 1= 19V
PIN 2= 19V
PIN 3= 19V
PIN 4= 19V (pretty sure this should be 26V)
PIN 5= 0V
PIN 6= 2.6V
PIN 7= 0V
PIN 8= 0V
PIN 9= 0V
PIN 10= 0V
PIN 11= 0V
PIN 12= 6.6V
PIN 13=...Leave a comment:
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Re: Lenovo Flex 2 14" LF14M MB Please help me to identify component
You're right...Just found out it's TI LM393 voltage comparator in TSSOP8 package......Leave a comment:
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Lenovo Flex 2 14" LF14M MB Please help me to identify component
Hi there...
Board No.:
LF14M MB
13281-1
448.00X01.0011
I've got Lenovo Flex 2 14" which doesn't charge battery. Sometimes it starts only for about 10 seconds & then cuts off. If I got lucky & manage to boot to windows, it shows battery fully charged with crossed battery icon. When I disconnect the charger it will cut off immediatelly. I can hear some buzzing noise from component PU4402 which says 49AG3 L393 on it (please refer to the pic). Any idea what component is it as I can't find schematic for this board? Thanks in advance....Last edited by loser18; 12-19-2018, 02:56 PM. -
Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
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 [B]below.
#1 Heads up:[/B]
My original KBC / IO chip was IT8528E [B]EXS [/B]. I've ordered [B]AXS[/B] & 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...Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
It's not fixed yet...BIOS didn't help...Waiting for new IT8528E & will post results once replaced......Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
Yes...Already did it...Also replaced SPI chip...Pls note that there's only one 4MB SPI on my mobo......Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
Yep, the correct voltage should be around 0.75V...I think 19V has been pumped in to AD_ID rail & it fried U14(KBC)...Will update once replaced...Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
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? I think it should be around 7-8 volts...Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
Yeah, but +3V is suspend voltage & it should come only after MAINON & SUSON......Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
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
The +3V should be suspend voltage so 0V is correct......Leave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
KBC Voltages:
PIN71=0.8V???
PIN11=1.8V???
PIN74=3.3V
PIN127=3.3V
PIN26=3.3V(assume all other VSTBY have correct voltage)
Resistance on PIN11 is about 114KΩLeave a comment:
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Re: HP 15-n027sa DA0U92MB6D0 not detecting charger / doesn't turn on
Ok...
So the issue seems to be KBC (U14) or +3V rail as reads only 1.8V on PIN11 (VCC)...
I'm tired AF, so will update tomorrow...Leave a comment:
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