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---- Amiga 4000 ----
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* Variants*


In 1992 September Commodore released the successor of the A3000 based around the AGA chip set. The first models were equipped with 040 processors only, later - to fill the gap between the A1200 and the A4000/040 - with 030 processors too. Apart from the used processor cards the two models are identical.

* Processor*

68030 @ 25-50 MHz
68040 @ 25-40 MHz
68060 @ 50 MHz
PowerPC 604e @ 150-233 MHz

Most desktop A4000s' processor is located on a removable processor card. The A4000/040 originally shipped with the A3640 featuring a 68040 or 68LC040 @ 25 MHz, and the A4000/030 with the A3630 featuring a 68EC030 @ 25 MHz and a socket for an optional 68881 or 68882 floating point unit. Some late A4000/030 has its processor soldered to the motherboard leaving the CPU slot empty.

* Memory *

up to 2 MB Chip RAM
up to 16 MB Fast RAM on motherboard
up to 128 MB Fast RAM on processor cards
up to 1 GB Fast RAM on Zorro III expansion cards

Most A4000s have five 72 pin SIMM sockets on their motherboard - one for Chip RAM, the other four for Fast RAM. The sockets accept industry standard 32 or 36 bit page mode SIMMs. The four parity bits of the 36 bit modules are ignored and they function as simple 32 bit ones. EDO RAM is not supported by the motherboard RAM controller, Ramsey, but some processor cards accept it and some even use its benefits.
The Chip RAM socket has to be filled with either a 1 or 2 MB SIMM. The four Fast RAM sockets accept 1, 4 or 8 MB modules up to a total of 16 MB Fast RAM. The SIMMs cannot be mixed and the 8 MB ones have to be placed in every second socket.
Late models have the four Fast RAM sockets only. The fifth socket is missing, it is replaced by 2 MB 70 ns Chip RAM soldered to the motherboard.
The access speed of the Fast RAM on the motherboard can be controlled by software, either 80 or 60 ns.

* Custom Chips *

Alice - AGA display controller
Lisa - AGA graphics coprocessor
Paula - audio and I/O controller
Fat Gary - system address decoder
Super Buster - DMA arbitrary controller
Ramsey - RAM controller
Bridgette - complex buffer
Kickstart ROMs

The A4000's AGA chip set offers the same screen modes as the A1200:
320256 - 1280512
320200 - 1280400
320256 - 6401024
320200 - 640800
400300 - 800600
50 Hz, 15.75 kHz
60 Hz, 15.75 kHz
50 Hz, 31.5 kHz
60 Hz, 31.5 kHz
72 Hz, 24 kHz
All screenmodes offer up to 256 colours from a 24 bit palette, or 262144 colours in HAM8 mode. Unlike the A3000 the A4000 has no separate flicker fixer, the 30 kHz modes are generated by the Lisa itself. Other screen modes require a Zorro graphics card.
In most A4000s Alice and Lisa is socketed allowing the upgrade to the canceled AAA chip set.
4 channel stereo 8 bit audio output with frequencies up to 28 kHz when using screen modes with 15 kHz, or up to 56 kHz when using screen modes with higher horizontal frequency. 16 bit audio requires a Zorro sound card.
All A4000s shipped with Kickstart 3.0 ROM which can be replaced with a 3.1 one. The access speed of the ROM is selectable by a jumper, either 160 or 200 ns.
Most A4000s have Super Buster revision 9 chips which turned out to be having problems with Zorro III cards using DMA. It can be replaced with revision 11, although early models have their Buster soldered to the motherboard. Late models shipped with revision 11 ones.

* Expansion slots *

1 processor card slot
4 Zorro III slots
1 extended video slot
3 inactive ISA slots

The Zorro, ISA and video slots are all placed on a daughterboard which is mounted vertically on the motherboard. All the ISA and video slots are in line with a Zorro III slot.
The video slot is extended with 18 pins not found in previous Amiga models in order to support the AGA chip set's 24 bit colour palette.
The three ISA slots have their power and ground pins activated only. In order to access the slots by the A4000 a BridgeBoard has to be installed. With an installed BridgeBoard two ISA AT compatible cards can be used in the remaining slots. Inactive slots can be used for non intelligent cards like TBCs or fan cards.
The processor card slot is physically the same 200 pin one which can be found in the A3000(T). However the processor cards designed specially for the A3000 do not fit into the A4000 because of their size - the A4000's daughterboard stands in their way.

* Drive Bays *

2 3.5" front bays
1 5.25" front bay
2 3.5" rear bays

One of the 3.5" front bays is occupied with a 1.76 MB high density floppy disk drive, and one of the internal bays with an - originally IDE - hard disk drive.
The 5.25" drive bay's depth is limited by the power supply thus longer devices, such as CD writers and some CD-ROM drives do not fit into it.

* Interfaces *

1 serial DB25 male, RS232
1 parallel DB25 female, Centronics
1 video DB23 male, analog RGB
2 mouse/game DB9 male
2 stereo audio RCA jack
1 keyboard 6 pin female mini-DIN
1 external floppy DB23 female
1 internal floppy 34 pin header
1 internal AT IDE 40 pin header
1 internal audio input 3 pin header

The built in IDE controller supports two IDE devices connected simultaneously. Unlike the A1200 the A4000 has a buffered IDE port. Only mode PIO 0 is supported.
The floppy drive controller supports up to four devices - two attached to the internal floppy header and two connected to the external floppy port. Both double and high density disk drives are supported.
The internal audio connector enables an audio expansion device mounted internally (e.g. CD-ROM, sound card) to mix its output into the standard Amiga audio output.

* Motherboard Revisions *

Revision A
A4000/030 with 68EC030 on A3630
A4000/040 with 68040 on A3640 v3.0 or v3.1
SIMM socket for Chip RAM
Alice and Lisa are socketed
Super Buster 9 soldered to motherboard
battery backed up clock
Revision B, C
Alice and Lisa are soldered to motherboard
socketed Super Buster 9
battery backed up clock
Revision D
A4000/030 with 68EC030 soldered to motherboard, socket for 68881 or 68882 on motherboard
A4000/040 with 68LC040 on A3640 v3.1
Chip RAM is soldered to motherboard
socketed Super Buster 11
lithium battery for the clock

* Power Supply *

150 W power output
monitor power connector
4 standard 4 pin power connectors
2 mini 4 pin floppy drive power connectors