laptop. This specific board is part of the Compal EL5C3, EL531, or EL431 series. Schematic Availability
If the laptop has no light, the issue is usually in the 3.3V/5V switching circuit. 4. VCC Backlight Circuit (JEDP1)
The LA-H103P motherboard is designed around an Intel architecture, typically supporting 10th Generation Intel Core processors (Ice Lake or Comet Lake) integrated directly onto the board (BGA package). Key Technical Specifications: Compal Architecture (LA series) la-h103p schematic
Use the schematic to identify the pinout for VCC_LCD and Backlight voltage on the JEDP1 connector. Troubleshooting Common LA-H103P Issues 1. No Power / Dead (No Lights) Action: Check for 19V/20V at the DC jack and MOSFETs. Action: Check for 3.3V at the BIOS chip (often U...). Action: Check for 3.3V/5V on the main coils. 2. Turns On & Off / No Display Action: Check CPU voltage (
Before the laptop turns on, these rails must be present to power the EC and BIOS chip. laptop
Identify the path from the DC jack through the MOSFETs to the CPU.
is a proprietary motherboard designed for Lenovo, specifically for the Lenovo IdeaPad S340-15IIL Troubleshooting Common LA-H103P Issues 1
Use the schematic to find the power button signal line. Verify that pressing the button sends a logic-level low (or high, depending on design) to the EC.
Understanding that this is an SoC (Processor, PCH, and Graphics on one silicon die) is vital. A short circuit on a low-voltage high-current CPU rail often means the entire SoC is dead, making the board unfixable without an expensive BGA rework station. 2. Power Architecture and System Rails
Understanding the architectural framework of the LA-H103P motherboard simplifies the diagnostic process when reading its schematic.
Someone had known. Someone had left a fix for a disaster they weren’t allowed to admit existed.