• Asus A550cc motherboard X550cc rev:2.0 no power

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#1 Asus A550cc motherboard X550cc rev:2.0 no power


by Amir 9 July 2024, 07:55
hi to all
Asus A550cc
motherboard part no : X550cc rev:2.0 not react to power button.
vga: 720M
cpu: core I3
3.3 &5 is ready and 3v in power button is also.
U3601 is get hot and remove no change.
kbc changed with new one and no change.
with battery charging Led is off(adaptor is connected)
bios re programed no change. if i touch pin 4 of PQ9101 laptop turns on and i have all voltage accept pl8001 &pl8004
please advise me
tnx

Re: Asus A550cc motherboard X550cc rev:2.0 no power


by Google Adsense [BOT] 9 July 2024, 07:55

#2 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by matic 9 July 2024, 08:35
Hello!

- Measure the resistances to ground on coils PL8100, PL8101.

- Measure the voltages to ground on pins 12, 17, 19, 57, 67, 74, 82, 107, 108, 112, 120, 121 of KBC chip.
- Measure the voltages to ground on pins 56, 125 of KBC chip in the following cases:
a) Power button released.
b) Power button pressed.

#3 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by Amir 9 July 2024, 10:03
hello
tnx matic
pl8100= about 1k
pl8101= 5 ohm
kbc:
pin12=1.8
pin17=3.3
pin19=0
pin 57-67-74=3.3
pin82=0
pin107-108-112-120-121=3.3v
pin 56 b=1.98 after=1.98
pin125 b=3.3 after=0
update:
I have to remind you that U3301 will get a little warm

#4 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by matic 10 July 2024, 08:24
Amir wrote:pl8101= 5 ohm
You have a short circuit to ground on 5V coil.

Amir wrote:I have to remind you that U3301 will get a little warm
So this chip is probably damaged, but it's not guilty for a short circuit on the 5V coil. You can remove this chip from the board and test the machine without it.

#5 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by Amir 10 July 2024, 09:08
hi
sorry for mistake...i have 5v in this coil and about 22k to gnd.both 3.3 and 5 v is ready(+3vO & +5VO)

#6 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by matic 10 July 2024, 09:55
Have you tested the board with the LAN controller chip U3301 removed from the board?

#7 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by Amir 10 July 2024, 10:26
LAN controller removed no change

#8 Re: Asus A550cc motherboard X550cc rev:2.0 no power


by matic 10 July 2024, 13:21
Voltage measurements on the KBC chip indicate a communication problem between the KBC and PCH chip.
Since you already reflashed the BIOS chip and replaced the KBC, the PCH chip is very likely damaged and needs to be replaced.

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