Facts

Facts


Facts

  • Manufacturer: Commodore
  • Type: Personal computer
  • Released: 1992
  • Discontinued: 1994
  • OS: AmigaOS 3.0 (upgraded to Amiga OS 3.1)
  • CPU: Motorola 68040 @ 25 MHz
  • Memory: 2-18 MB
  • Predecessor: Amiga 3000
  • Successor: Amiga 4000T
  • Storage: 120 MB HDD, HD 3.5" floppy drive

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 cheaper 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 (The cheaper A4000/030EC 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.

Amiga 4000 in my jobs
After school 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.

Recap, repair traces
I cleaned the A4000 real good as usual and got it professionally recapped (new capacitors) at “Retro-service”, a one-man driven workshop for retro-computers. Some broken circuit traces was repaired there as well, a battery leak had caused the damage. A new battery holder for the real time clock was put in place as well.

Repair 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.

More RAM and setting up an memory card as harddrive
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 had an A2088XT IBM PC emulator card laying around as well, and got it installed. 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 4 MB SIMM modules costed a fortune back in 1992-93.

The A4000 was already upgraded to Kickstart 3.1 ROM and the newer Super Buser rev. 11 chip (the original rev. 9  chip is know to cause problems). Now my Amiga 4000 works perfectly.

Commodore A2088 PC emulator board along with an VGA ISA 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 very well in an Amiga 4000 as well of cause. It’s the slowest PC-emulator card in the series though, and features 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 work, this PC 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 in the gallery bellow.

Next I installed a BIOS patch than made the card run at 7 MHz instead of 4.7 MHz, 50% speed increase. I’ve got my hands on an NEC V20 8 MHz CPU and replaced the Intel 8088 chip. This CPU is compatible but is said to be a little bit faster with 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.

Soldering/manufacture 68040 CPU card
I’ve got my hand of a bare A3640 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. 

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 accidently shorted the IDE controller on the computers mainboard when testing this, and now my A4000 will not boot at all. Waiting for parts to get the built in controller fixed.

 

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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