Which component is checked last if a video problem persists after BIST?

The system board is typically the last component checked when diagnosing a video problem that persists after the Built-In Self-Test (BIST) has been performed. This is because the system board is a critical component that interfaces with multiple hardware elements, including the processor, memory, and graphics capabilities. If the BIST indicates that the initial self-checks are passed, it often implies that the more common issues, such as external connections or simpler components like the LCD cable or inverter board, have already been ruled out.

In most troubleshooting procedures, the system board is assessed after other components because defects in the board can lead to a wide range of problems, including video issues that are not correctable by simple fixes. If the previous checks (like that of the LCD cable or inverter board) do not reveal the source of the problem, attention turns to the system board because it may affect overall functionality and is generally more complex and costly to replace. Therefore, confirming whether the system board is functioning correctly is a critical step when the problem persists after initial tests.