Hello,
My Asus laptop does not power up anymore. It does not work on battery nor on the charger.
None of the LED lit up and the CPU fan does not start.
I have tried removing the RAM to boot but it does not help.
The laptop has not suffered from any water damage / shock.
- Laptop model: F301-RX073V (similar to X301A)
- Motherboard: X401A Rev 2.0
- Charger: 19V 3.42A AC to DC
I have tear down the laptop to extract the motherboard and began testing basic things:
- The power supply does deliver 19V as expected.
- I can measure 19V across the connector pins on the motherboard.
- I have tested the power button, it's resistance drops to zero when pressed.
- The capacitors on the motherboard look OK: none on them is stained or deformed.
There are inductors, MOSFETS and ICs near the power connector but I am not sure what to check first and how to.
Components I have identified:
- 2D5 27 25V electrolytic capacitors
- 2D3 560 2.5V electrolytic capacitors
- A5 GNA 802807 (MOSFET)
- 4955N RWS09 (MOSFET)
- R360 1215F inductors
- Richtek RT8885A IC: Dual Output 3-Phase + 2-Phase PWM Controller (
https://www.richtek.com/Products/Vcore/Vcore%20Controller/RT8885A?sc_lang=en)
When the motherboard is connected to the power supply I measure 4V across the 25V capacitors (does not feel right) and 0V across the 2.5V capacitors
Pictures of the motherboard:
This connector is where the power supply comes from:
This is where I measure 19V. The wires go to another board on which there is the barrel jack.
If there are particular chips you want pictures of or detailed description please ask!
I have:
- A logic analyzer (no analog input)
- A multi-meter (no capacitance mode)
- Iron / tin / flux
- Patience
What would you check next to narrow down the problem?
Bye!