Hello everybody
I am facing to a consistent problem with my mother's Lenovo G50-80 with ACLU4-NMA361 motherboard. CPU is Core i5 5200U and GPU R5 M330. When I plug on AC adapter or turn it on by button, power led (LED4) is on and fan starts to spin and all stops few seconds later.
First, I removed BGA GPU R5 M330 because package was physically brocken. NO CHANGE
I measured several voltages following what should be normal power sequence :
A1) VIN : 20V
A2) B+ : 20V
B2) +3VLP : 3.37V
A3) EC_ON : 3.37V
B3) ON/OFF 3.37V button not pressed, 0V when pressed
A4) +3VALW : 3.38V
1) DPWROK_EC : 3.37V
2) PCH_PWR_EN# : 3.38V
3) +3VALW_PCH : 3.37V
4) PCH_RSMRST#_R : 3.37V
5) PBTN_OUT# after button press : 3.3V for 350ms, 0V for 100ms, then 3.3V continuous
6) PM_SLP_S3# : 3.3V for 300ms and then 0V
PM_SLP_S4# : 3.3V for 300ms and then 0V
7) SYSON : 3.3V
8) SUS_VCCP : 3.3V for 400ms and then 0V
9) SUSP#: 5V for 400ms and then falling to 0V
+CPU_CORE : 1.65V for 400ms and then 0V
I removed PJ707 (solder shunt B+ to +VGA_B+), changed nothing.
When I remove PQ40(CPU phase High-side MOSFET), the laptop seems to NOT turn off (power led still brighting, voltages present,...) but obviously, +CPU_CORE is 0V… so cannot boot.
Idem when I remove PJ708 (solder shunt B+ to PQ40 drain) or (PL9 self of the phase).
I don't find any short, I removed PQ40, test it : was OK, change it, same result.
Strange fact : On circuit, measured resistance on PQ40 between source and drain is more than 250kohms but when I plug AC adapter, remove it and measure this resistance, it drops to 1.2ohms for lots of minutes (problem or capa discharging ?)
I don't know what to do, please could you help me ?
Thanks
I am facing to a consistent problem with my mother's Lenovo G50-80 with ACLU4-NMA361 motherboard. CPU is Core i5 5200U and GPU R5 M330. When I plug on AC adapter or turn it on by button, power led (LED4) is on and fan starts to spin and all stops few seconds later.
First, I removed BGA GPU R5 M330 because package was physically brocken. NO CHANGE
I measured several voltages following what should be normal power sequence :
A1) VIN : 20V
A2) B+ : 20V
B2) +3VLP : 3.37V
A3) EC_ON : 3.37V
B3) ON/OFF 3.37V button not pressed, 0V when pressed
A4) +3VALW : 3.38V
1) DPWROK_EC : 3.37V
2) PCH_PWR_EN# : 3.38V
3) +3VALW_PCH : 3.37V
4) PCH_RSMRST#_R : 3.37V
5) PBTN_OUT# after button press : 3.3V for 350ms, 0V for 100ms, then 3.3V continuous
6) PM_SLP_S3# : 3.3V for 300ms and then 0V
PM_SLP_S4# : 3.3V for 300ms and then 0V
7) SYSON : 3.3V
8) SUS_VCCP : 3.3V for 400ms and then 0V
9) SUSP#: 5V for 400ms and then falling to 0V
+CPU_CORE : 1.65V for 400ms and then 0V
I removed PJ707 (solder shunt B+ to +VGA_B+), changed nothing.
When I remove PQ40(CPU phase High-side MOSFET), the laptop seems to NOT turn off (power led still brighting, voltages present,...) but obviously, +CPU_CORE is 0V… so cannot boot.
Idem when I remove PJ708 (solder shunt B+ to PQ40 drain) or (PL9 self of the phase).
I don't find any short, I removed PQ40, test it : was OK, change it, same result.
Strange fact : On circuit, measured resistance on PQ40 between source and drain is more than 250kohms but when I plug AC adapter, remove it and measure this resistance, it drops to 1.2ohms for lots of minutes (problem or capa discharging ?)
I don't know what to do, please could you help me ?
Thanks
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