Adjusting The Monitor Geometry
Use one of the hexagonal tools to adjust the geometry and brightness/contrast.
The brightness and contrast adjustments are located on the side of the logic board.
The monitor geometry adjustments are located on the back of the logic board.
Follow the diagram below for these adjustments.
After you finish adjusting, turn on the computer.
You're all done and you now have a 640x480-capable Color Classic .. congratulations!
Got a narrow screen (row 4 in the digram above) or bad barrel distortion (row 5) if you widen it too far? Try this fix.