Hello everyone,
I need your advice in diagnosing a motherboard issue on a Lenovo IdeaPad 3 15ITL05, motherboard HS45A/HS55A Rev 1.0 NM-D461 (2020-11-02).
Symptoms:
The laptop does not power on and does not respond to the power button.
Background:
According to the owner, her child was playing on the laptop when it suddenly shut down.
What has been done so far:
Original charger is missing; the non-original one was tested and found faulty (0 V output).
Using a lab power supply (20 V, 0.5 A) — no activity on the board, no LEDs, no standby voltages.
20 V present at the DC jack and PQ100 (MOSFET), but missing at PQ101.
PU100 receives 20 V.
Power consumption 0.030–0.050 A.
The battery (Lenovo L16L2PB3, 7.6 V nominal, 8.7 V charging) was deeply discharged.
Initially 0 V output, BMS locked.
Each cell ~3.2 V, recharged to 4.2 V, but BMS still locked (0 V total).
MOSFET PQ101 (SM3319) was shorted and replaced with the same model.
After replacement, the board shows signs of life:
Orange BATT_CHG_LED turns on when battery is connected.
Battery controller unlocked; charging voltage 8.49 V, battery voltage 8.36 V.
On power button press: fan spins, CPU warms up (no heatsink now), power button and PWR_LED blink.
Current rises to 1.8 A, then drops to 0.3–0.4 A (charging). Without battery – 0.036 A.
Screen stays black, no image on internal or HDMI output.
Voltage measurements:
PJ5901 (V9B+): 8.38 V (battery) / 19.9 V (AC adapter)
PJ5902 (3VALW): 3.35 V in both cases
PJ5601 (V9B+): 8.38 V / 19.9 V
PJ5602 (+5VALW): 5.09 V / 5.11 V
I’ll attach motherboard photos and schematic below.
Question:
Could you please advise which section I should check next, or what could prevent the board from turning on the display?
Thank you!
Schematic - https://www.badcaps.net/forum/troubl...atic-boardview
I need your advice in diagnosing a motherboard issue on a Lenovo IdeaPad 3 15ITL05, motherboard HS45A/HS55A Rev 1.0 NM-D461 (2020-11-02).
Symptoms:
The laptop does not power on and does not respond to the power button.
Background:
According to the owner, her child was playing on the laptop when it suddenly shut down.
What has been done so far:
Original charger is missing; the non-original one was tested and found faulty (0 V output).
Using a lab power supply (20 V, 0.5 A) — no activity on the board, no LEDs, no standby voltages.
20 V present at the DC jack and PQ100 (MOSFET), but missing at PQ101.
PU100 receives 20 V.
Power consumption 0.030–0.050 A.
The battery (Lenovo L16L2PB3, 7.6 V nominal, 8.7 V charging) was deeply discharged.
Initially 0 V output, BMS locked.
Each cell ~3.2 V, recharged to 4.2 V, but BMS still locked (0 V total).
MOSFET PQ101 (SM3319) was shorted and replaced with the same model.
After replacement, the board shows signs of life:
Orange BATT_CHG_LED turns on when battery is connected.
Battery controller unlocked; charging voltage 8.49 V, battery voltage 8.36 V.
On power button press: fan spins, CPU warms up (no heatsink now), power button and PWR_LED blink.
Current rises to 1.8 A, then drops to 0.3–0.4 A (charging). Without battery – 0.036 A.
Screen stays black, no image on internal or HDMI output.
Voltage measurements:
PJ5901 (V9B+): 8.38 V (battery) / 19.9 V (AC adapter)
PJ5902 (3VALW): 3.35 V in both cases
PJ5601 (V9B+): 8.38 V / 19.9 V
PJ5602 (+5VALW): 5.09 V / 5.11 V
I’ll attach motherboard photos and schematic below.
Question:
Could you please advise which section I should check next, or what could prevent the board from turning on the display?
Thank you!
Schematic - https://www.badcaps.net/forum/troubl...atic-boardview
Attached Files