If you have a CM-4 on your bench, you are likely dealing with one of these common legacy issues:
Suppose you have a carrier board with no power. The CM-4 requires 5V DC on pins 1, 2, 3, 4 (VIN). Here is how you use the boardview to fix it. cm-4 94v-0 boardview
On boards marked CM-4, the most common points of failure are the entry MOSFETs and the ceramic capacitors near the CPU/GPU power rails. If you have a CM-4 on your bench,