TOPIC The screen is black, boot tone is present, drive operates, 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, boot tone is present, drive operates, fan is running, and LED is lit. Products affected 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.
2. Remove all third-party devices. 3. Reseat the video card. 4. 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. 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. Power Macintosh G4 (PCI Graphics): Reset Cuda chip. Refer to article 95065: " Power Macintosh G4 (PCI Graphics) Resetting the Cuda Chip" .
9. Reset 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 |
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