This is not a model number . It is a UL (Underwriters Laboratories) flammability rating standard. A 94V-0 rating certifies that the fiberglass substrate (FR4) used to manufacture the PCB will self-extinguish within 10 seconds during a vertical burn test and will not drip flaming particles.
The CM4 breaks out a single-lane PCIe Gen 2 bus and dual HDMI interfaces. Because these lines are regularly exposed to external hardware on custom IO baseboards, Electrostatic Discharge (ESD) frequently blows out the tiny protection diode arrays near the interface pins. If your CM4 boots but fails to display video or recognize PCIe devices, these diodes are your primary target. How to Utilize a CM4 Boardview File for Repair
Use a microscope to inspect the Hirose connectors for bent or corroded pins. Check the PMIC for small burn holes or discoloration.
The USB, HDMI, and PCIe lines use differential pairs (two traces running perfectly parallel). If you must repair these traces, keep the jumper wires exactly the same length to avoid signal skew and data corruption.
Assuming you have obtained an exclusive .brd file for a CM4 carrier board (94V0 rated), follow this workflow:
The CM4 abandons the traditional edge-connector of the CM3 in favor of two 100-pin high-density Hirose mating connectors on the bottom of the board.
