Technical information

Troubleshooting Testing for Power - 10
Testing the Power/Analog Board Fuse
First remove the bottom housing, front outer bezel, and the top
rear housing to access the power/analog board. The fuse is located
near the AC plug.
Warning: You must unplug the iMac to do a continuity test at the
power supply board fuse.
You will need an ohm meter to do a continuity test on the power
supply board fuse. Refer to the picture below to located the neces-
sary test point referenced in the following procedure.
Unplug the computer to take this reading. Using an ohm meter,
touch the red and black probes to the two metal points at location
F901 and check for continuity (reading of “0”). If the ohm meter
registers “0”, the fuse is good. If the meter registers “infinite”,
the power/analog/video board should be replaced. A bad fuse is
indicative to a power/analog/video board problem.
Note: To take
this reading, it’s easiest to insert the red probe of the meter
through the opening on the back side panel.
Testing Fuse 901 for Continuity