If all voltages are correct, the SPI Flash BIOS chip ( UH2 or similar label on the board) is likely corrupted. This motherboard is highly prone to BIOS firmware errors. Desolder the chip, back up the corrupt dump, and flash a verified clean ME-region BIOS file using an external programmer (like the RT809F or CH341A). 5. Tips for Utilizing the Schematic and Boardview
: Integrated Intel Kaby Lake-U (7th Gen) dual-core processors (e.g., i3, i5, i7).
How to Use the LA-E801P Rev 2.0 Schematic for Troubleshooting la-e801p rev 2.0 schematic
If +3VALW is missing, the laptop will appear completely dead and will not respond to the power button. +1.2V / +1.2V_DEEP (RAM Power Rail)
Essential for tracking down power rail short circuits via safe, low-voltage injection techniques. If all voltages are correct, the SPI Flash
Search for KB9022 in the schematic. Verify pins like VCC (power supply), WRST# (Reset signal), and EC_RST# . If the EC is not getting power or remains locked in a reset state, it will never assert the PM_PWRBTN# signal to wake the Intel CPU.
If you are currently debugging an LA-E801P board, let me know you are experiencing (e.g., completely dead, spinning fan with no post, or not charging) so we can pinpoint the specific pins or voltage rails to test. Share public link Connectivity & I/O Interfaces
Looking at the schematic, locate the feedback loop. This usually involves an optocoupler (often labeled PC1 or IC901 on the diagram) and a precision shunt regulator (like the TL431). If you are troubleshooting a unit that has no output but the fuse is fine, this is your first stop. The Rev 2.0 schematic highlights a slight change in the compensation network around this shunt regulator compared to Rev 1.x. This was a factory fix to reduce output ripple under heavy load—knowing this helps if you're wondering why your replacement components aren't stabilizing the voltage as expected.
Input MOSFETs (usually dual N-channel MOSFETs configured as reverse-polarity and over-voltage protection), current sensing resistor ( PR302 or similar depending on exact schematic notations).
: MEC1416-NU, managing power sequencing, keyboard input, and thermal monitoring. Connectivity & I/O Interfaces