User Guide

Troubleshooting General/ Testing for Power - 8
Note:
The procedure below tests for +5 V on the Version 2 (661-
2167) power supply board.
First remove the top access cover and then remove the CRT EMI
shield to reach the power supply board.
±
Warning:
In this next procedure, the power supply will be
exposed and the unit plugged in. Use extreme caution and avoid
touching the exposed power supply to avoid any shock hazard when
working on an open unit.
You will need a volt meter to test for power on the power supply
board. Refer to the picture below to locate the necessary test
points on the power supply board.
Ground the black probe of a volt meter to the computer chassis.
Plug in the iMac, but leave it powered OFF. Then, being careful not
to short together any pins, touch the red probe on the volt meter to
pin 3 on the power supply board and test for +5V.
Testing for Power on the Version 2 Power Supply Board