Optical Drive, ONLY, Displays Odd Colors

Restarting my PowerBook from Micromat's TECHTOOL PRO (Version 4) DVD running in the computer's optical drive produces an off-color and barely readable display. Otherwise this computer, after an excellent iFIXIT-orchestrated hard drive swap-out and RAM upgrade, seems to be running extremely well. While it is not the quietest, the original optical drive is accepting and playing CDs and DVDs. But the unusual display appearance, when restarting out of a diagnostic DVD that operates correctly on other computers, has me wondering whether the optical drive is close to failure. Any advice in how to specifically troubleshoot a questionable optical drive would be appreciated.