SCSI CD problem


I have a SCSI CD and a DVD RAM Drive on my PowerMac G3 Beige 400mhz (i change processor) and when i have 10.0.4 everything go fine, i update to x.1 over x.0.4 and the scsi cd still work, but i have to erase my hd and when reinstall the scsi cd dont work anymore, i install again x.0.4 and later x.1 but nothing, in classic it work, what i do bad?