Thanks judysings for taking up this issue,
Your suggestions haven't addressed the issue. Points 1 - 3 are not it. the disc, all discs I try are fine. 4, the disc can't be inserted far enough for the mechanism to activate. There is a mechanical stop on the right side that prevents the disc from being inserted, probably the one that prevents a second disc from being inserted when there is a disc in the drive. 5, You can wait all day, it won't happen. #6 has been done, no change.
In trying to resolve this issue I went to Disk Utility. Launching and quitting it. In doing so I could here the drive click. The disc then goes in and operates perfectly. When the disc is ejected then again another disc can't be inserted because of the lock. Re-launch Disk Utility, and the drive reacts. A disc is insertable. It just seems that the drive's default position is to lock out the insertion of a disc unless Disk Utility is launched. This leads me to believe there's a bug in the system as opposed to a physical problem with the drive.