3.5" disk drive problems...

[graalguy@yahoo.com (Ian Gowen)]

I currently have:
  Apple ][gs
  PC-to-appleII NULL-modem cable
  apple 3.5" Disk drive

I have no "known good" disks.
I start up the machine. The drive light comes on, I get the "Scrolling
apple" 'Check startup device!" message. The drive light goes off.
I send the hex dump of EmDos thru the null-modem; checksums are
correct.
I type "INIT HELLO" with a disk in the drive; it hangs for about a
second, and it gives me "Disk Error: I/O". The drive light DOES NOT
COME ON at all.
Does anyone have any idea what is going on here?
Also the system battery is dead. Don't think this matters, though.
-Ian