The DKB 3128 is a full-length Zorro-III memory expansion board for the A3000(T) and A4000(T) Amiga computers.

The DKB 3128 accepts up to 4 32-bit SIMMs of 4, 8, 16 or 32 megabytes in size for a total of 128MB of add-on memory. The SIMMs you choose should be 80 ns or faster.

The SIMM sockets hold the installed SIMMs parallel with the DKB 3128 circuit board so the DKB 3128 remains low profile even with SIMMs installed.

If you install SIMMs larger than 4MB you will need to remove one or more jumpers from the SIMM size jumpers. If you install an 8 or 32 megabyte SIMM module, you must remove the shorting block on J1. If you install a 16 or 32 megabyte SIMM module, you must remove the shorting block on J2. Jumper J3 is not used and should not have a shorting block on it. Note: The DKB 3128 circuit board is silk-screened with this information.

You can mix SIMM sizes on the DKB 3128 but you must put the largest SIMM in the second SIMM socket labeled "BANK 1" below. Additionally, if you mix SIMM sizes, you must install the included 3128 program at the beginning of your startup-sequence. If you do not, the system will assume every module is the same size as the largest and add "phantom" memory which isn't actually there. Running your system in this state is not a good idea. The disk that comes with the DKB 3128 includes the 3128 and an installer script to install it.

Memory on the DKB 3128 is not as fast as motherboard memory in the A4000, about 80% of normal A4000 memory speed according to AIBB.

Board Layout
  _________________________________________________________________
 |   123                         ____     ____     ____     ____   |___
 |   :::                          | |      | |      | |      | |   |
 |   SIMM                         | |      | |      | |      | |   |
 |   Size                        B| |     B| |     B| |     B| |   |
 |                               A| |     A| |     A| |     A| |   |
 |                               N| |     N| |     N| |     N| |   |
 |                               K| |     K| |     K| |     K| |   |
 |                                | |      | |      | |      | |   |
 |                               0| |     1| |     2| |     3| |   |
 |                                | |      | |      | |      | |   |
 |                                | |      | |      | |      | |   |
 |                               _|_|     _|_|     _|_|     _|_|   |
 |                                                                 |
 |_________________________________________________________________|
     |||||||||||||||||||||||||||                                   |

  SIMM Size Jumper Settings

      4MB 8MB 16MB 32MB
  J1   L   R    L    R
  J2   L   L    R    R

  R = Remove
  L = Leave Installed

  J3 should never be installed.