Glossary

The vocabulary of schematics, boardviews and firmware, in plain language.

BIOS / UEFI
The firmware that initialises hardware and starts the operating system, stored in an SPI flash chip on the board.
Board number
The identifier printed on the PCB by the manufacturer (for example LA-E891P or 820-00165). It identifies the exact design and is the key to finding matching documentation.
Boardview
A file describing the physical layout of a PCB: the position of every component, pad and net. Opened with a boardview viewer such as OpenBoardView.
CH341A
An inexpensive USB programmer for 24/25-series chips. It outputs 3.3 V, so a 1.8 V adapter is required for low-voltage flash chips.
Diode mode
A multimeter measurement of the voltage drop from a net to ground. Comparing readings with a known-good board finds shorted or open lines without powering the board.
DMI data
Machine-specific information inside the BIOS: serial number, product name, UUID, and often the Windows licence key. It must be carried over when a dump from another machine is used.
Dump
A full binary copy of a flash chip, read with a hardware programmer.
EC (Embedded Controller)
A microcontroller that manages power buttons, charging, keyboard and fans. Its firmware lives either inside the main BIOS chip or in a separate small flash chip.
ME / CSME
Intel Management Engine, a subsystem with its own firmware region inside the BIOS chip. A corrupted or "dirty" ME region can stop a board from booting; a "clean ME" dump has that region reset to its factory state.
Net
An electrical connection shared by several pins. Clicking a net in a boardview highlights every pad on it.
ODM
Original Design Manufacturer — the factory that designs and builds a board for a brand. Compal, Quanta, Wistron, LCFC, Inventec and Pegatron are the main laptop ODMs.
PCH
Platform Controller Hub — the Intel chipset that handles I/O. A failed PCH is a common cause of a board that has all standby rails but never starts.
Power sequence
The order in which rails and enable signals must appear for the board to start. A missing step in the sequence is the usual lead when a board will not power on.
Rail
A power-supply net, such as +3VALW (3.3 V always-on) or +VCORE (CPU core voltage).
Schematic
The electrical circuit diagram of a board, normally a multi-page PDF organised by function (power, CPU, memory, I/O).
Short to ground
A fault where a rail is connected to ground through a failed component, typically a ceramic capacitor or a MOSFET.
SPI flash
The 8-pin (SOP8 / WSON8) memory chip that stores firmware, usually from the 25-series (W25Q64, GD25Q128, MX25L…).
Test point
An exposed pad on the PCB used by factory test fixtures; boardviews list them as "nails".