check to see if the scsi cables are properly and firmly connected and that the zip disks have actual information on it and also be very careful connecting and disconnecting the drive while the mpc is on i heard that can blow a fuse witch can cause the scsi not to work no more on it
YO I HAVE THE SAME PROBLEM WITH A ZIP FULL OF NEW STUFF I HAD BEEN WORKING ON. WHAT CAN I DO, I KNOW THE ZIP DRIVE AND THE MPC ARE WORKING CAUSE OTHER DISK WORK OKAY, THIS DISK WAS WORKING OKAY, I TOOK IT OUT THE HOUSE AND NOW IT DONT WORK ANY MORE. WHAT CAN I DO TO SAVE THE DATA ON THE DISK.
i have had the same problem before. its usually the channel. but also if you hook up the zip drive after you have the mpc on, sometimes it doesnt work properly. so always have the drive hooked up before you turn on the mpc.