The spin up/spin down behavior is common among zorched drives. Most drives perform some sort of power-on self-test. If certain key tests fail, the drive decides that there's no point in spinning, and shuts off.

The fix? Replacement, generally. Almost any 50-pin scsi drive will do (and with adapters, other than 50-pin drives can work). There may be limitations on the size of a partition (2GB), but you can have lots of partitions, so a modern drive will do fine (in fact, it will do wonders).