TITLE
    Power Mac G4: Screen Is Black, Not Boot Tone, LED is Lit
Article ID:
Created:
Modified: 		95039
7/14/00
12/27/00
TOPIC

    The screen is black, there is no boot tone, drive does not operate, but fan is running and LED is lit.

DISCUSSION

    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 screen is black, there is no boot tone, drive does not operate, but fan is running and LED is lit.

    Products affected

    • Power Mac G4
    • Macintosh Server G4

    Solution

    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. For the Power Macintosh G4 (PCI Graphics) computer, check jumper block at J25. Make sure it is the correct color for the processor type, that it includes all required inner metal clips, and is installed in the correct direction. See "Processor Module" in Service Source Take Apart for more information.

      2. Check all video cable/card connections and connector pins.

      3. Power Macintosh G4 (PCI Graphics): Reset Cuda chip. Refer to article 95065: " Power Macintosh G4 (PCI Graphics) Resetting the Cuda Chip" .

      4. 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 PCI Logic Board ".

      5. Reseat the video card.

      6. Reseat the SDRAM DIMMs.

      7. Reseat processor module.

      8. Remove all SDRAM DIMMs and try replacing them one at a time to test. Replace any bad DIMMs.

      9. Replace the video card.

      10. Replace processor module.

      11. Replace logic board.

      12. Replace power supply.



Document Information
Product Area: Power Mac G4
Category: Power Mac G4 Hardware
Sub Category: Troubleshooting
Keywords: kpmg4, kssts

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