connects to: Other
A4000 with manuals and disks
Front of A4000
Rear of A4000
A4000 Rev B Motherboard - bare, Front
Hi Res version, A4000 Rev B Motherboard - bare, Back
Hi Res Version, Front of A4000
- 2592 x 1434, 516K
Hi Res Version, Black A4000
- 1484 x 652, 71K
A4000 Rev B Motherboard, Front
- 2529 x 1770, 1,465K
A4000 Rev B Motherboard, Back
- 2337 x 1665, 1,309K
A4000 Rev D Motherboard
- 1134 x 596, 135K
A4000 Rev B Daughterboard
- 2490 x 918, 553K
A4000 Rev 1 Daughterboard
- 2997 x 1076, 756K
Image of US A4000 Keyboard
- 2544 x 894, 426K

Standard Specifications


Case Type: Desktop
Processor: EC030@25Mhz (on motherboard for A4000-CR models)
EC030@25Mhz via a Commodore A3630
040@25Mhz via Commodore A3640
MMU: None (030 versions)
Internal (040 version)
FPU: Optional, but not standard (030 versions)
Internal (040 version)
Chipset: AGA
Kickstarts: V3.0 (2 ROMs)
Bus Controller: Buster Rev 7 (Prototype A4000 only)
Super Buster Rev 9
Super Buster Rev 11
Expansion Slots: 4 x 100pin Zorro III slots
1 x AGA Video slot (inline with Zorro)
3 x inactive 16bit ISA slots (inline with Zorro)
1 x 200pin CPU Fast slot.
Standard CHIP RAM: 2MB
RAM sockets: 4 x 72pin SIMM slots (A4000-CR only, 2MB Chip is surface mounted)
5 x 72pin SIMM slots (one slot is reserved for Chip RAM)
Hard Drive Controllers: 1 x 3.5" Buffered IDE Controller
Drive Bays: 1 x 5.25" (with faceplate, None for Black A4000)
4 x 3.5" (2 with faceplates)
Note: Some machines were supplied with 1.5 times height floppy drives, in this case the second externally accessible 3.5" bay is fairly useless as it's only half height.
Expansion Ports: 1 x 25pin Serial
1 x 25pin Parallel
1 x 23pin RGB Video
1 x 23pin External Floppy
2 x 9pin Joystick/Mouse
2 x RCA Audio (Left/Right)
1 x PS/2 style Keyboard Connector
Floppy Drive: 1 x Internal 1.76MB Floppy Drive
Note: Some machines were shipped with single height drives, others had 1.5 times height drives.
Motherboard Revisions: Rev 1 (Early prototype, with black case)
Rev B (Most Common)
Rev C (Rare)
Rev D (A4000-CR)
Battery Backed Up Clock: Yes, uses "Barrel" shaped batteries, except Rev D which uses "Coin" shaped batteries.

The A4000 is often seen as the big brother of the A1200 but was targetted more at productivity users, rather than gamers. The A4000 was seen as a disappointment to many after the reception that the A3000 received. Although it uses a newer ROM and Chipset, the onboard SCSI-II had been replaced with a significantly slower IDE Controller (PIO Mode 0) and it did not contain the scandoubling hardware for attaching PC VGA type monitors which the A3000 did. Significant improvements were however, made to the Zorro III bus design particularly with regards to DMA and bus mastering that fixed many problems which plagued the A3000, providing you had a Rev 11 buster. Unlike most other big box Amigas the A4000 uses a PS/2 style keyboard connector, however the signals and keyboard clock that the A4000 uses are not the same as the PC so you cannot use PC PS/2 keyboards. Like most big box Amigas the A4000 also has a keylock which effectively works by removing power from the keyboard and mouse rendering the machine fairly useless.

Some A4000's may have been released which contained 020 CPU's, as the A3630 that was supplied with the A4000 can also be fitted with an 020 and there is one claim that Commodore donated an 020 based A4000 as a prize at The Gathering '92. A4000's with a Rev D motherboard differ slightly from the other versions and are dubbed "A4000-CR" which stands for "Cost Reduced". It was an attempt to reduce the cost of manufacturing the A4000. Most A4000's were shipped with a separate processor card connected to the CPU fast slot however the A4000-CR had an 030 soldered directly to the motherboard therefore a processor card was not required. It still contained the CPU fast slot however for attaching accelerators. In addition to this Commodore also removed the fifth SIMM slot which is reserved for CHIP ram and soldered the CHIP directly to the motherboard. As all A4000s were supplied with 2MB CHIP by default, the fifth SIMM slot was rather useless because the AGA chipset could not address more than 2MB of CHIP. Commodore had planned to give the A4000 the ability to address up to 8MB of CHIP and indeed a jumper can be found on the motherboard which would have been used for this purpose, but the jumper actually does nothing.



Function Jumper Setting Description
CLK 90 Clock Source J100 1-2 Internal (020/030)
    2-3 External (040)
CPU Clock Source J104 1-2 Internal
    2-3 External
ROM Speed J151 1-2 200ns
    2-3 160ns
CHIP RAM Size J213 1-2 2MB
    2-3 8MB (Non Functional and never will be!)
Second Internal Floppy J351 ON No second internal floppy or second internal floppy is 1.76MB
    OFF Enabled second 880K floppy as DF1:
Redirect DF0: J352 1-2 Internal DF1: and DF0:, External DF2: and DF3:
    2-3 Internal DF1: and DF2:, External DF0: and DF3:
Enable DSACK J850 OFF Required if CPU is 020. Also requires U860 and U152
RAM SIMM Size J852 1-2 2MB or 4MB SIMMs
    2-3 1MB SIMMs
Video Type J212 1-2 NTSC
    2-3 PAL
VBB/MA10 J214 1-2 Supplied VBB to Alice
    2-3 Alices supplies MA10 for 8MB CHIP (Non Functional and never will be!)
Video Sync J500 1-2 Sync on Green Disabled
    2-3 Sync on Green Enabled
    2-3 DEFAULT
DAC Sync J502 1-2 DAC sync on green
    2-3 DAC uses standard signal