We bought Raspberry Pi 3 B+ kits In October for an after school program and are having issues with 2 of the boards. We get an HDMI not connected error message just for 2 of the boards. All of the other boards are working and connected with no problems.
Could someone give us some guidance on how to get them up and running. We’ve done some initial troubleshooting and can’t seem to determine what the issue is - SD Card?