The Power Mac G4 computer does not turn on. There is no fan movement.

This article covers repair procedures for authorized service providers on selected Apple products, but we have published them in the Knowledge Base for the general public for educational purposes. At this time, there are a limited number of repairs that a customer can perform and these are covered under the customer installable parts program http://www.info.apple.com/installparts . If you have not been authorized to perform these procedures, please contact Apple (800-APL-CARE in the USA) or your local authorized service provider to schedule a repair.

Symptom

The Power Mac G4 computer does not turn on. There is no fan movement.

Products affected

• Power Mac G4
• Macintosh Server G4

DANGER! This procedure exposes you to high voltages that can result in death or serious injury. DO NOT ATTEMPT THIS PROCEDURE IF YOU HAVE NOT BEEN CERTIFIED AS AN APPLE-AUTHORIZED TECHNICIAN.

1. Power Macintosh G4 (PCI Graphics): Check LEDs DS7 and DS8 on the logic board. In a working unit, these LEDs should be in sync with each other: both on or both off. If one LED is on and the other is off, there is a problem.

2. Verify power outlet is good. Try a known-good power cord.

3. Make sure the voltage switch on the back of the power supply is set to the correct voltage.

4. Check for trickle voltage the power supply connector.
- Power Mac G3 (Blue and White) and Power Mac G4 (AGP Graphics/PCI Graphics): refer to article 58561: " Power Macintosh G3 (Blue and White) and Power Mac G4: Power Supply Voltage Tes t".
- Power Mac G4 (Gigabit Ethernet): refer to article95064: " Power Mac G4 (Gigabit Ethernet): Power Supply Voltage Test ".

5. Disconnect the keyboard and press the power button on the front of the computer. If the computer turns on, replace the USB keyboard. If not, go to next step.

6. Power Macintosh G4 (PCI Graphics): Reset the Cuda chip and try again. Refer to article 95065, " Power Mac G4 (PCI Graphics): Resetting the Cuda Chip ".

7. Reset the logic board:
- Power Mac G4 (AGP Graphics/Gigabit Ethernet): Refer to article 95037, " Power Mac G4 (AGP Graphics/Gigabit Ethernet): Resetting the PMU on the Logic Board " .
- Power Macintosh G4 (PCI Graphics): Refer to article 95066: " Power Macintosh G4 (PCI Graphics): Resetting the Logic Board ". If the situation still persists, go on to the next step.

8. Replace the logic board.