Facts

  • Type: Personal computer
  • Released: 1992
  • Discontinued: 1994
  • Introductory price: US$1,285 (US$2,900 in 2017 equivalent)
  • Operating system: AmigaOS 3.0 (later 3.1)
  • CPU: Motorola 68040 @ 25 MHz
  • Memory: 2-18 MB
  • Resolutions: 320×200 to 1504x576i
  • Palette: 24-bit (16.8 million colors)
  • Manufacturer: Commodore
  • Audio: 4 × 8-bit PCM channels (stereo), 28–56 kHz
  • Built-in media: 3.5″ HD floppy drive (1760 KB)
  • Internal media: 120 MB 3.5″ IDE (ATA) hard drive
  • ROM: 512 KB Kickstart
  • Expansion slots: Zorro III, AGA video slot, ISA-16 slots, CPU slot, SIMM slots
  • Chipset: AGA (Advanced Graphics Architecture)
  • Successor: Amiga 4000T

Released 1992: The Commodore Amiga 4000, or A4000, is the successor of the Amiga 3000 computers. There are two models, the A4000/040 released in October 1992 with a Motorola 68040 CPU, and the less expensive A4000/EC030 released in April 1993 with a Motorola 68EC030 CPU.

The Amiga 4000 introduced the Advanced Graphics Architecture (AGA) chipset with enhanced graphics, capable of displaying 256 colors from a palette of 16.7 million. In HAM-8 display mode, over 262.000 colors can be displayed at once, although with some artifacts.

An HD floppy drive and the included “CrossDOS” software allows the A4000 to use MS-DOS 1.44 HD floppy disks in addition to Amiga formatted 1.76 MB disks. Some of the cost reduced A4000/EC030 might only got DD floppy drive, and some of the later Escom produced Amiga 4000 in some cases only got DD floppy drive.

The SCSI system from previous Amiga’s was replaced by lower-cost PATA (IDE) controller, sporting the use of cheaper PC-style IDE hard drives. In the end of 1993, only months before the demise of Commodore, an  tower version called the A4000T was released. The bigger A4000T had more expansion slots and a built in SCSI-2 f/w hard disk controller in addition to the PATA.

The Amiga’s Motorola 68040 Central Processor Unit (CPU) is not mounted directly on the motherboard, but instead on a separate CPU-board. This board plugs into the CPU slot on the motherboard. Later A4000EC/030 revisions got the CPU mounted directly on the motherboard and leaves the CPU slot empty.

Amiga 4000 as its predecessors makes up a very expandable system. Numerous options and upgrades were developed by third party companies, independent of Commodore.

Amiga 4000 computers at my school
I was very trilled and excited when I got my hands on an second hand Amiga 4000/EC030 around 1993-94, and payed a small fortune for it. I was lucky enough when studying graphic design at school 1994-95 as the schools choice of computers was not Mac’s at everyone else, but Amiga. The computer room was filled up with Amiga 4000 computers.

Me at school in 1994, using the Amiga 4000 for graphic design.
Me at school in 1994, graphic design using an Amiga 4000.

3D graphics
I was astounded first time I saw 3D rendered animation and heard about “Raytracing”, around 1989. Shortly after I got an Amiga, it became my hobby. These made these images on my Amiga 4000 in the 90’s using a program called Real 3D. Real3D from two brothers and a company called Realsoft in Finland, was one of the most advanced 3D programs on any home computer back then, the learning curve was steep though.

Real3D had ground breaking features such as cubic b-splines, simulations based on Newton’s laws of motion, morphing based animation techniques and phenomenal rendered output. Version 2 did not subdivide B-splines to polygons prior rendering but used an advanced approach where surfaces got subdivided on the fly during rendering. It also took full advantage of the multi-tasking abilities of the Amiga – allowing the user to continue editing a scene on another window while rendering. For animations, a collision detection system did not use bounding boxes but used the true shape of objects. Real3D was the first software being able to detect and solve exact collisions between all supported geometries, such as hyperboloids and cubic B-spline surfaces.

Amiga 4000 at my job
After graduating, I worked with info channel systems (information and interactive TV) installed in cruise ships, using Amiga 4000T computers. We also used the Amiga 4000 computers for production in the office. In my next job, I also got in touch with Amiga 4000T computers, making multimedia and info channel for some of the clients that still had their aging Amiga systems running (why replace something that works?). I was also hired in as a freelance by a print office, to help them with setting up Amiga info channel system at TV-sets at some local post offices etc.


Repairs and upgrades

I was informed by the seller that the computer was unstable and probably needed a replacement of the capacitors. I was lucky to get it at a bargain price. It fired up but started to malfunction after some minutes, some of the keys was not working at the keyboard as well.

New capacitors and repair of bad traces
First I cleaned the A4000 real good as usual. Then I got it professionally recapped (new capacitors) at “Retro-service”, a one-man driven workshop for retro-computers, whom got microscope and the equipment needed to inspect for damages caused by leaked electrolyte and so on. A battery leak had caused some damage around the battery area and corroded pins from memory controller chips, this was taken care of and a new battery holder for the real time clock was soldered in place as well.

Repaired keyboard
I opened the keyboard and measured conductivity, “invisible” cracks in the keyboard membrane obviously caused the malfunction of keys. I tried to repair it by using conductive paint I bought cheap from eBay, but the paint turned out to not be conductive as supposed to. I bought a second hand Amiga 500 keyboard membrane with the same part number as the Amiga 4000 membrane. After replacing the membrane, the keyboard worked perfectly.

A4000 - replacing keyboard membrane
A4000 – replacing keyboard membrane

Setting up a CF-card as hard drive
Next, installed a 4 GB CF memory card with an PATA IDE adapter as an hard disk and copied the Amiga OS 3.1 setup from my Amiga 1200. I used a hacksaw and a drill and modified an adapter for mounting it in the rear expansion lid at the rear of the Amiga 4000. In that way it’s really easy to access it and it doesn’t occupy any expansion slots.

CF-card mount
CF-card adapter mounted in the rear

Adding RAM
The A4000 also seemed to have two defect or incompatible SIMM RAM modules fitted and I got new ones very cheap from eBay, so it got fully populated to 18 MB RAM. I remember getting just a 4 MB SIMM modules costed me a fortune back in 1994.

Super Buster and custom Kickstart ROM
The A4000 was already upgraded to Kickstart 3.1 ROM and the newer Super Buster rev. 11 chip (the original rev. 9  chip is know to cause problems). Finally, my Amiga 4000 works perfectly. Because I now have upgraded to re-engineered A3640 CPU board with modifications to use an 68060 CPU, I needed to replace the two Kickstart 3.1 ROM chips with two custom ones. The Kickstart ROM chips are always in socket, so that part is easy on all Amiga models.

Installing Commodore A2088 PC emulator together with an VGA card
I already had an Commodore A2088 PC XT emulator card laying around to be installed. This card was initially made for the much older Amiga 2000 model and followed up from the Commodore A1060 XT emulator sidecard for the Amiga 1000. The card works in an Amiga 4000 as well, as the Zorro III slots are backward compatible with Zorro II.. A2088XT is the slowest PC-emulator card in the series though, and features only a 4.7 MHz Intel 8088 CPU. The big boxes Amiga’s from Amiga 2000 and up, got inactive ISA expansion slots in addition to Amiga Zorro and video expansion slots, that the PC-emulator card “activates”, so normal PC cards can be used by the emulator.

I’ve was lucky enough to find an 486 PC in the electrical waste at my work, it happened to have an VGA ISA card, which I removed to be used by the emulator card in my Amiga 4000. After a little fiddling, it worked out perfectly, added a picture of the Amiga running PC on a separate monitor with the game Prince of Persia in VGA.

Next I installed a BIOS patch than made the card run at 7 MHz instead of 4.7 MHz, a 50% speed increase. I’ve got my hands on an NEC V20 8 MHz CPU and replaced the Intel 8088 chip. This CPU is said to be a little bit faster handling instructions internally compared to the original CPU. I then did some hardware modifications to the board to make it run at ~10 MHz, twice the original speed. Unfortunately this didn’t work, I’ve got the BIOS boot display, the memory check OK and everything, but the BIOS seemed to alert something and it wouldn’t boot from my hard drive “image, maybe it distorted the cards own floppy disk controller, and this prevented me from boot. Anyway, I reversed the hardware mod and let it run at ~7 MHz again.

Later, I got my hands on the A2286 AT emulator board, featuring a 286 CPU @ 8 MHz and 1 MB RAM.

My A4000 with A2088 PC emulator, VGA card to separate monitor on left.

Soldering 68040/68060 CPU card
I’ve got my hand of a bare A3640/060 PCB with all parts as an “assemble myself” kit. The board was re-engineered by John Hertell and is a “modified” remake of the 68040 CPU board that originally came with the Amiga 4000 back in 1992. My A4000 had its 040 board replaced by the much slower 68030 board that came with the less expensive Amiga 4000EC/030 when I got it. 

Unfortunately, when I was finished soldering all the components and doubled checked everything, my Amiga 4000 would not work with the card fitted. I also accidentally shorted the IDE controller on the computers main board when testing this, and now my A4000 will not boot at all. Waiting for parts to get the built in controller fixed.

A3640 CPU board, soldering
A3640 CPU board, during soldering

New motherboard
Long story made short. Ended up getting a new motherboard and exchange my non-working 040 CPU daughter card and the faulty motherboard with a new working 040 card from John Hertell in Sweden (Chucky). Some capacitors were not soldered in, but they were shipped along with the card and I got no problem solder them in place. Great, finally up and running again.

Upgrade to 68060 CPU
A good thing, the new CPU card I got is a newer revision that the first one, which John has integrated the earlier needed adapter for a 68060 CPU into the card itself. I only had to solder in a voltage regulator and relocate a resistor. It ran fine at stock 50 MHz, but I wanted to overclock it to modest 64 MHz. The A4000 wouldn’t boot at fist when the 64 MHz oscillator was fitted, but by relocating a resistor to another position on the card that works better with overclocking, the machine ran 100% stable, luckily. I now get around 94 faster CPU than an stock Amiga 500/600, according the the “less reliable” benchmark program SysInfo. My Amiga 4000 feels really fast now, also the hard drive “IDE CF card” speed up from 1.5 MB sec up to around 2.5-3.2 MB sec. Now, I run it at 66 MHz, and stable.

A3640/060 re-engineered with Motorola 68060 running at 66 MHz.
A3640/060 re-engineered with Motorola 68060 running at 66 MHz.
SysInfo 68060@64 MHz
SysInfo benchmark program measuring CPU speed (68060@64 MHz).

Upgrade with 256 MB additional RAM
Ordered the BigRAM+ z3 board from AmigaKit store that gives 256 MB extra fast RAM. Now the Amiga 4000 got 274 MB RAM in total, so much more than ever needed, but 18 MB was tiny for running MacOS 7.6 with Photoshop in emulator concurrently with Amiga OS for example.

Running Amiga OS 3.1 and Mac emulator
Running Amiga OS 3.1 with lots of RAM and Shapeshifter Macintosh emulator.

Adding a  RTG graphic card
I get hold of an Retina BLT graphic card. It’s a Zorro III (32 bit expansion slot) card with 4 MB graphic RAM. Amiga AGA chipset graphics uses only “bitplane” graphic modes which makes using a lot of color in productivity software very slow compared to chunky mode. Graphic card provides chunky modes, increased speed and resolutions. “Picasso96” RTG graphic drivers in Amiga OS provides support for this for system friendly software. Software that misses settings to use an user selected graphic mode, can be “promoted” to do so by using a “screen promoter” running in the background, a small program that forces other programs to start in an user selected screen mode.

My A4000 at Solskogen computer party in 2018.
My Amiga 4000 next to an Amiga 1000 at Solskogen computer party in 2018.
Amiga 4000

Remi Jakobsen


I'm collecting classic computers and video games, stretching from the 70's into the 90's. Restoration, history, usage ...


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2 thoughts on “Amiga 4000

    1. Thank you very much.

      I think the “Chucky” reverse engineered “remake” of the 3640 (3660) got a modification to the amount of delay in the delay line for timings to suit overclocking better. WHen I first tried to run at 64 MHz, my machine would not even go to boot screen. I then simply re-positioned an existing resistor to another position to suit overclock better, I don’t remember exactly what resistor it was anymore. After this, it ran 100% stable at 64 MHz. Currently, I run it at 66 MHz, and it runs 100% stable, I think this is the limit though. I tested shortly with 70 MHz, the machine booted, but proved unstable, the timings was messed up at this clock speed. I also had an 3630 CPU board that came with the Amiga 4000/030 and replaced the Amiga 4000 on-board osc with an 64 MHz oscillator chip to run it at 32 MHz without any other modification, this was 100% stable.

      A bit about overclocking here: http://members.iinet.net.au/~davem2/overclock/a3640.html

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