Technical information

Troubleshooting Symptom/Cure Tables: Startup Problems Before the Finder
No Video or Unstable Raster
Normal startup boot chime, the LED is on, and the hard drive starts up. The display,
however, is solid gray.
Possible Cause Possible Fix
Corrupted PRAM. - Reset parameter RAM. Hold down <Command> <Option>
<P> <R> during startup before “Welcome to Macin-
tosh” appears.
Corrupted system soft-
ware.
- 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.)
No: Go to next step.
The PMU chip or logic
board needs to be reset.
- Press the PMU chip on the logic board with the AC
power cord disconnected. (See “The PMU Chip” and
“Resetting the PMU on the Logic Board” mentioned
earlier in this chapter.)
- Connect the power cord and power on the system again.
Do you have power to the system now?
Yes: Test the unit with MacTest Pro and return the
computer to the customer.
No: Plug in the AC power cord and reset the PMU chip
again. Do you have power to the system now?
Yes: The battery is likely bad, check the battery.
No: Go to the next step.
Bad video cable connection. - Verify that the CRT video board cables, the RGB cable,
and P701 (the deflection yoke cable on the power/
analog board) are securely attached. If the problem
persists go on to the next step.
Bent CRT neck pins. - Remove the CRT video board. Check that the pins on the
CRT neck are not bent. Carefully reseat the CRT video
board and power on the computer. Do you have video
now?
Yes: Run MacTest Pro and return the computer to the
customer.
No: Go on to the next step.