Install boot options for the LC 475.CDROM?Other?

The LC 475 is a slightly faster/improved version of the LC III - which I have. Those Macs will boot from an external SCSI device, such as a hard drive or CD-ROM drive. Years ago, I used those peripherals with mine without any problems. To start up from an alternate (bootable) device connected to the SCSI bus, when you power ON the LC, immediately/simultaneously hold down the Command + Option + Shift + Delete keys.

" I have discovered that the Mac OS floppies no longer work."

When a disk is inserted, does the floppy drive attempt to read it or is the drive completely dead? Were the floppy disks formatted as Mac OS Extended on a newer Mac? If so, they need to be formatted as Mac OS Standard. If you transfer each of the (OS 7.5.3) segments from the (19) Mac OS floppy disks to the hard drive, when you double-click the first segment, the installer image will be created on the desktop.

" Or are there any other options besides buying a USB floppy drive."

Unfortunately, any USB device will not be compatible with your LC 475, because its proprietary LC-PDS expansion slot doesn't support industry-standard devices, like PCI cards.

You should also buy/install a new 3.6-volt, ½AA lithium battery for the motherboard. If the computer has been disconnected from electricity for an extended period of time, the battery is probably very weak or dead.

Can't say enough in agreement with Jeff about getting a new PRAM battery. Our Performa 475 (same machine) will kill a PRAM battery in short order if off the mains for longer than a few days. Knowing the battery is fresh can save a bunch of troubleshooting steps.

I recall that holding the "C" key during startup to boot from an external CD-ROM like we do with Macs having built-in optical drives didn't work on older Macs with SCSI externals. We had to use the "DOCS" shortcut (delete option+commandshift) combo to boot the 475 from our external SCSI drive.

Allan