User's Manual

Troubleshooting Symptom/Cure Tables:Startup Problems Before the Finder Appears
Bad power/analog/video
board
-Verify the fuse at F901 on the power/analog board is
good. (Refer to “Testing for Power at the Power/
Analog Board Fuse” mentioned earlier in this
chapter.) Did you get a “0” reading?
Yes: Check/reseat all power/analog/video board cable
connections. Make sure the video board is securely
attached to the CRT neck. If the No Power problem
persists, go on to the next step.
No: Replace the power/analog/video board.
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 :
Replace the power/analog/video board.
Bad down converter board - Check for DCO voltage at location C10 on the logic board
(Refer to “Testing DCO (Down Converter On) Voltage
at C10 on the Logic Board”) mentioned earlier in this
chapter). Did you measure approximately
-1.2 volts?
Yes
: Go on to the next step.
No
: Replace the down converter board.
Bad LED Power Switch
Board
- Replace the LED/power switch board (922-4160).
If that doesn’t solve the problem, go on to the next step.
Bad CRT - Replace the CRT.
In a “No Power” situation, the system is completely dead. There is no LED, no hard
drive power, and the screen is completely black. (Refer to “Testing for Power” ear-
lier in this chapter for instructions on how to test for power at each component refer-
enced in this procedure.)
Possible Cause Possible Fix