If you swap the Kickstart ROM for a DiagROM chip you can run the diagnostics programs.

Insert the diagnostics ROM into the BIOS ROM slot.

When first turned on you should have a dark grey, then flashing green, then horizontal multicolored lines, followed by a brief light green then white screen before the final diagnostics screen appears.

In order for the DiagROM to be able to control the screen, it needs to have the following chips working and traces good: