Hello,
  I do have 501-2462, which appears to be OK. It is a connecter
switcher from SCA80 to SCSI-2(i.e. narrow) 50-pin things.
  And there was the ribbon cable attached to it, one end of which
(actually there were two of those) is the narrow SCSI-2 male and the 
other end is the plainest 50-pin SCSI-1 female. There cannot be
any awkward things.

  I think I need to be careful about 2 things: 1) feed the right
electricity (I say this because I am not sure if the power-source
is compatible with PCs); 2) make sure the hard drive is of
single ended type.

  If that doesn't work, you can buy the adapter which isn't expensive.

Cheers,
Tsuji