Apple iMac G5, 20-inch - Manual (Page 241)

iMac G5, 20-inch Troubleshooting - 17 Troubleshooting Power Issues
8. While doing the power supply repair, inspect the capacitors (highlighted below) on the
logic board, looking for signs of bulging and/or venting.
9. Affected capacitors will have a “+” sign stamped into the top of the capacitor. Note:
Not all capacitors stamped with a “+” sign are faulty, so further inspection is required to
determine whether one or more of the capacitors are faulty.
Warning: Use caution when handling failed electronic components, and make sure
to wash your hands afterwards.