La-d402p Schematic May 2026

Guide to the LA-D402P Schematic

1. What is the LA-D402P?

• Board Number: LA-D402P (printed directly on the PCB)
• Common Models: Lenovo IdeaPad 330-15AST, 330-17AST, 330S-15AST
• Key Components: AMD A9/A6/ E2 series CPU, AMD Radeon R5 graphics, internal battery management, USB-C power delivery (on some variants).

Page 40-45: BIOS and SPI Flash

• BIOS Chip: Typically a 25Q64 or 25Q128 (8MB or 16MB).
• Lines: CS# (Chip Select), SO (Data Out), SI (Data In), CLK (Clock).
• Note: The LA-D402P schematic rarely includes the actual BIOS firmware code, but it shows the pinout and the connection to the PCH. A corrupt BIOS is a common "no display" issue.

The LA-D402P schematic is primarily used by technicians for: Power-On Issues

Signal Probing: Checking if the BIOS/PCH SMBUS communication is active when the laptop fails to POST. Where to Find Schematics la-d402p schematic

The LA-D402P motherboard (often labeled as the "BAL20" series) supports the following primary components: Guide to the LA-D402P Schematic 1