Ground the red probe of your multimeter. Use the black probe to test key voltage rails (VCC_MAIN, VBUS) against your schematic link map to check for short circuits to ground.
You can view detailed structural documentation on the E7A MB PCB V3 Wiring Diagram on Scribd , which details the physical appearance and location of on-board filters, diodes, and ICs. e7a mb pcb v3 link
The integration of improved drivers dramatically reduces motor noise, making the Ender-3 V3 SE significantly quieter during operation. Ground the red probe of your multimeter
Inspect the physical MIPI filter arrays located directly adjacent to the camera or LCD flex connector sockets. Cracked solder joints under these filters frequently break data continuity. Accessing Schematics and Resources e7a mb pcb v3 link