A590, Front right

A590, Front left

A590, Rear

A590, base

Hi Res Version, A590, Front right - 832 x 720, 82K
Hi Res Version, A590, Front left - 788 x 654, 53K
Hi Res Version, A590, Rear - 795 x 606, 66K
Hi Res Version, A590, base - 564 x 778, 51K
Image of A590 with case off showing SCSI HD - 921 x 694, 104K
Image of A590 with case off showing SCSI HD from rear - 1040 x 942, 157K
Image of A590 with case off showing XT HD - 776 x 529, 111K
Image of A590 box - 860 x 658, 104K
Image of A590 box, open - 1002 x 1142, 158K
Image of motherboard - 2547 x 1707, 930K

The A590 is a hard drive controller which connects to the side expansion slot of the A500(+). It provides both a SCSI controller, and an XT controller. An XT Controller is the very old 8 bit IDE standard (not to be confused with ST506). Whilst it uses the same 40pin IDE cable that modern IDE controllers use, you cannot use modern IDE drives with the XT controller because they are 16 bit. You must use XT hard drives. These were only ever made up to about 80MB in size. The A590 was usually shipped with a 20MB Seagate SCSI drive by default or a 20MB Western Digial XT drive but the drive specifications are printed on the base of the unit.

There are several versions of the ROMs for the A590, Version 6 ROMs only allow hard drives up to 512MB in capacity. Version 6.6 and 7.0 ROMs have been reported to work successfully with drive sizes up to 9GB but you will need at least OS3.5 to use drives over 4GB. Notice the names of the LEDs on the unit, named Fred and Wilma.

DIP Switches

Switch 1
OFF: Disables Autoboot ROMs (Kickstart 1.2)
ON: Enables Autoboot ROMs (Kickstart 1.3)

Switch 2
OFF: LUN Disabled (One Drive at each address)
ON: LUN Enabled (Multiple drives at each address)

Note: Some SCSI drives such as certain Seagate and Epson drives, respond to more than one logical unit address (LUN). Such drives will appear on the Workbench screen and the Hard Drive Preparation, Partitioning, and Formatting screen in HD Toolbox multiple times, at the same Address but at LUN 0 through 7. If this occurs, set switch 2 to OFF.

Switch 3
OFF: Short wait period for drive to spin up. Parity checking enabled
ON: Long wait period Parity checking disabled for message in phase

Switch 3
Time-Out Length: If you are using a SCSI drive that takes longer than 30 seconds to start up when you turn the system on, such as some seagate drives, you may wish to set switch 3 to ON. When the switch is in the OFF position the time-out period, the time between power-on and when the system checks the drive, is short.

Switch 4:
Reserved (e.g., don't mess with it!)

Jumper Settings

Note: The A590 is shipped with all jumpers set to 1 by default

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