Troubleshoot Display Black boot from DVD
1. Wife reported display with abnormal characters, and eventually going black
2. Apple Store Genius diagnosis as GPU Assembly failure
3. Purchased refurbished GPU Assembly from DV warehouse, tested by DV ok, 90 day warranty
4. Installed refurbished GPU
5. Power-on after installation.
6. 1st attempt to load Mac OS X from DVD to internal hard drive Disk (replaced internal hard drive since we had the computer completely opened), installation proceeded normally, then display goes black, computer appears to be still powered on.
7. Next attempt, display goes black within a few minutes.
8. Went to Apple store, recommendation to use an external monitor
9. Installed external monitor
10. Powered on, using external monitor, booting from install disk
11. Apple chime, dialog windows prompts to install OS, everything proceeding normally.
12. Apple desktop display showing on internal monitor and external monitor
13. Mac OS X installation progress bar is displayed on the internal monitor, gets down to 28 min.
14. External monitor displays just the desktop background
15. Internal monitor goes black.
16. External monitor goes black.
17. External monitor sync goes from green to amber
So, what should I focus on next to isolate the problem?