Amiga 2000 ALF2 Scsi Controller.. Need help

[JimS]

What size HD are you trying? A lot of old cards won't deal with drives over 1GB, sometimes not even seeing them.
Every device on the SCSI bus has an address from 0-7. Usually, the controller card is hardwired to 7. Drives usually are jumpered as 6 from the factory.
You need proper termination on the bus, generally resistor SIPs on the drive itself, near the connector.

[JimS]

There should be three jumpers on the drive labeled A0,A1,A2 which make up the drive address. It's binary, with jumper on meaning "1". So A0 off, A1 on, A2 on would be address 6, and usually safe.