TITLE
    Power Mac G4: Screen is Black, Startup Tone Present, Drive Operates
Article ID:
Created:
Modified:
95055
7/18/00
4/23/01

TOPIC

    The Power Mac G4 computer screen is black. There is a boot tone, the drive operates, the 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 Power Mac G4 computer screen is black. There is a boot tone, the drive operates, the fan is running and LED is lit.

    Affected Products

      • Power Mac G4
      • Macintosh Server G4
      • Macintosh Server G4 with Mac OS X Server
    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. Check video cable/card connections and connector pins.

      2. Remove all third-party devices.

      3. Reseat video card.

      4. Power Mac G4 (PCI Graphics): Check jumper block at J25. Make sure jumper is correct color for processor type, includes all required inner metal clips, and is installed in correct direction. See "Processor Module" in Service Source Take Apart for more information.

      5. Clear parameter RAM. Hold down Command-Option-P-R during startup but before "Welcome to Macintosh" appears.

      6. Reseat SDRAM DIMMs. Make sure DIMMs are PC-100 DIMMs.

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

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

      9. Reset the logic board. Power Mac G4 (AGP Graphics): Refer to resetting the PMU in article 95037: " Power Mac G4 (AGP Graphics/Gigabit Ethernet): Resetting the PMU on the Logic Board ". If you have a Power Macintosh G4 (PCI Graphics): Refer to article 95066: " Power Macintosh G4 (PCI Graphics): Resetting the Logic Board" .

      10. Test with known-good monitor. Replace monitor if necessary. Refer to appropriate monitor manual to troubleshoot defective monitor.

      11. Replace video card.

      12. Replace processor module.

      13. Replace logic board.



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

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