It passes through an input fuse, an EMI filter circuit, and two isolation MOSFETs (usually controlled by the charging IC, e.g., ISL88739 or similar).
A thorough reading of the LA-D402P schematic would reveal the "power sequence"—a strictly ordered startup routine managed by a PMIC. The schematic illustrates the necessary feedback loops and enable signals that ensure the 3.3V rail activates before the 1.8V rail, for instance. Furthermore, the schematic details the protection circuits: fuses, thermistors, and MOSFET switching transistors that guard against over-voltage and short circuits. Without the schematic, diagnosing a "no power" condition on the LA-D402P would be akin to navigating a maze blindfolded; with it, a technician can trace the voltage path meter by meter to find the exact point of failure. la-d402p schematic
The schematic—his phantom map—told him that ACDET came from a voltage divider: two resistors in series from the 19V rail. He found them on the board. A 100k and a 12k. He measured the 100k. It read 100k. He measured the 12k. It read… 3 megohms. Open. Dead. It passes through an input fuse, an EMI
Ensure the revision (e.g., Rev 0.2) matches the schematic version. He found them on the board
Due to the proprietary nature of the hardware, the schematic is not publicly released by the manufacturer. However, through reverse engineering observations and component diagnosis, this report outlines the architecture, key circuit subsections, and diagnostic approach for this specific board.
The is a technical blueprint for the BKE31 motherboard, commonly found in premium ultrabooks like the HP Spectre 13-v and HP Spectre 13-v100 series . This compact, high-density motherboard supports 7th-generation Intel Core i5 and i7 processors, integrated Intel HD Graphics, and 8GB of onboard RAM. Core Technical Specifications LA-D402P motherboard Go to product viewer dialog for this item.