Harman Kardon HD 7400 Displays E, won't play

Hi folks,

I have a Harman Kardon HD 7400 CD player, recently refurbished and upgraded.

When I put a disc in, I can hear the motor spin up and the display will read the total time and tracks.  When I hit PLAY, it displays a capital E. I assume this means error. No sound is produced. I can't find anything on the net that pertains to error codes for this model. Any ideas? Thanks.