CD Duplicator Fault

We have a Wytron CD Duplicator CD-398 Model:SD9CD S/N: J12115308744A The top CD-RW drive is not burning any disks. The tray will open, but when all trays (9 in total) are full, the machine only picks up 8 of them. You have to select the start button to begin the copying process whereas previously this was automatic (When 9 dics are detected). When the copying process is complete, all drives eject automatically (to show sucess) except the top CD-RW because I beleive it is faulty.