If your CM4 turns on but fails to output video via HDMI or interface with PCIe devices, you likely have a broken trace or a bad solder joint under the high-density connectors.
The most common point of failure is a short circuit on a power rail, often caused by a failed ceramic capacitor or a blown PMIC. cm4 94v0 boardview exclusive
Dropped boards or thermal stress can cause micro-fractures in the inner layers of the PCB, severing lines between the SoC and the high-density connectors. Set your multimeter to resistance/diode mode. If your CM4 turns on but fails to