Technical information

Troubleshooting Symptom/Cure Tables: Startup Problems Before the Finder
Bad power/analog/video
board
- Check for trickle power on the logic board (Refer to
“Testing J9 for +5 V Trickle Power on the Logic
Board” mentioned earlier in this chapter). Trickle
power is present as soon as the power cord is plugged
into the computer.
Did you measure +5 V trickle power on pin 1 of
connector J9?
Yes: Go to the next step.
No: Refer to the troubleshooting symptom “No Power”.
Bad logic board Check for DCO voltage at location C4 on the logic board
(Refer to “Testing DCO (Down Converter On) Voltage
at C4 on the Logic Board”) mentioned earlier in this
chapter). Did you measure approximately
-1.2 volts?
Yes: Go to the next step.
No: Replace the logic board.
Bad internal RGB video
cable.
- Replace the internal RGB video cable that attaches to
the power/analog/video board and to the logic board.
The cable is screwed to the power/analog board,
located near the AC power plug on the power/analog
board.
- If this doesn’t solve the problem, go to the next step.
Bad power/analog/video - Replace the power/analog/video board.
Bad CRT. - Replace the CRT.
Normal startup boot chime, the LED is on, and the hard drive starts up. The display,
however, is solid gray.
Possible Cause Possible Fix