User Guide

Troubleshooting Symptom Charts/ Video Problems - 21
A predominant color
tint or color covering
the screen.
1 Verify that the iMac unit is not near other equipment (such
as speakers, radios, phones, fluorescent lighting, magnets, or
other electronic equipment) that could affect the video
display. If necessary, move the iMac computer to another
area and restart the unit.
2 Reseat the video cable connecting from the interconnect board
to the main logic board. Make sure that both ends of the cable
are firmly seated into their connectors. The interconnect
board to logic board video cable routes behind the CD-ROM
drive. If the connection to the interconnect board is not
firmly seated, pushing on the CD-ROM drive can move the
video cable enough to cause an intermittent connection.
3 Reseat the internal RGB cable at J5 on the A/V interconnect
board and at P301 on the analog/video board.
4 Replace the analog/video board. Exhange like-for-like, there
are two versions of this board.
5 Replace the internal RGB cable that runs between J5 on the
A/V interconnect board and at P301 on the analog/video
board.
Erroneous text or
characters appear on
the screen
1 Boot off the system CD that came with the unit. Do you see a
normal screen display now?
Yes : Reinstall system software. (You must use the system
software CD that came with the unit to get the correct version of
Mac OS with the appropriate iMac enablers.)
No : Go to next step.
2 Remove any VRAM DIMMs and restart the unit. Does the
screen display appear normal now?
Yes : Replace the existing VRAM DIMMs with known-good VRAM
DIMMs.
No
: Go to next step.
3 Replace the logic board.