Commodore Amiga 3000 Motherboard Rev B2 #1, A3000 (As-Is) For Sale


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Commodore Amiga 3000 Motherboard Rev B2 #1, A3000 (As-Is):
$132.50
Appearance: UsedFunctionality: Not Working - Missing pictured, a Commodore Amiga 3000 Motherboard, Rev. B2. Board is missing chips and presumed not working – sold as-is.
Warranty and Returns:=====================This product is being sold AS-IS without any warranty. Returns are not accepted. To ensure that this is the right product for your needs, we’re happy to answer any questions.
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In 1990 Commodore released its first 32 bit system featuring the ECS chip set. The first models had 16 MHz motherboard, later 25 MHz.The A3000UX is based around the 25 MHz model. It shipped with AT&T Unix System V Release 4 operating system instead of AmigaOS, a three button mouse, and usually with the A3070 tape streamer, the A2410 graphics card and the A2065 Ethernet card installed.
Processor
68030 @ 16-25 MHz68040 @ 25-40 MHz68060 @ 50 MHzPowerPC 604e @ 150-233 MHz
All A3000 has a 68030 processor and a floating point unit soldered to its motherboard. The A3000-16 uses 68030 and 68881 @ 16 MHz while the A3000-25 uses 68030 and 68882 @ 25 MHz. Upgrading the processor requires the use of a processor card.The A3000s shipped with empty processor card slots.
Memory
up to 2 MB Chip RAMup to 16 MB Fast RAM on motherboardup to 128 MB Fast RAM on processor cardsup to 1 GB Fast RAM on Zorro III expansion cards
All A3000s have 1 MB Chip RAM (eight 44256k 120 ns DRAM DIPs) soldered to their motherboard. Eight 20 pin DIP sockets accept another 1 MB.Fast RAM can be installed either via DIPs or ZIPs. Eight 20 pin DIP DRAM sockets accept 4 MB and 32 ZIP sockets accept 16 MB Fast RAM. The ZIP sockets are split into four banks (bank 0-3), where the first bank is hardwired to the DIP Fast RAM sockets (bank 0). Thus the two types of Fast RAM cannot be used together in bank 0. The ZIP DRAM sockets accept either 1M×4 or 256k×4 80 ns ZIPs in groups of eight (one bank) but all the banks have to have the same sized chips. The RAM chips can be either static column or page mode ones. Static column ones support burst memory access and so they perform 10% faster.Many A3000s shipped with 1 MB 80 ns Fast RAM installed in the DIP sockets, which were intended to be moved to the empty Chip RAM sockets later on.
Custom chips
Fat Agnus - ECS display controllerSuper Denise - ECS display encoderAmber - display enhancerPaula - audio and I/O controllerFat Gary - system address decoderFat Buster - DMA arbitrary controllerRamsey - RAM controllerSuper DMAC - DMA controllerLow resolution screen modes offer up to 32 colours from a palette of 4096, 64 in EHB mode or 4096 in HAM mode. High resolution screen modes offer 16 colours from 4096, super-high resolution and productivity modes offer 4 colours from a palette of 64. Other screen modes require a Zorro graphics card.The display enhancer deinterlaces or doubles the scan rate of the 15 kHz video modes allowing the use of VGA style monitors. 31 kHz modes can be generated also by Fat Agnus itself but they use up more DMA bandwidth and cannot be deinterlaced by Amber. The display enhancer can be disabled with a toggle switch and can be fine tuned with a trimpot on the back panel of the A3000.4 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.Early A3000s have Kickstart 1.4 softboot ROM. It loads a ROM image (revision 2.04 or 3.1) from a bootable drive, reallocates memory with the 030's MMU and turns 512 kB Fast RAM into ROM. Kickstart 1.4 does not work with 040 or 060 processors because their MMU is different. Most A3000s shipped with Kickstart 2.04 ROM. Both versions can be replaced with a 3.1 one. The ROM timing circuit provides four different speed settings for output enable (90-345 ns) and access timing (160-437 ns).All A3000s shipped with DMAC 01 or 02, Ramsey 04 and Fat Buster 05, 06 or 07. Upgrading to DMAC 04 and Ramsey 07 solves many problems with some 040 processor cards, especially the A3640. Upgrading to Super Buster 11 enables Zorro III DMA which is required by some expansion cards, for example the A4091.
Expansion slots
1× processor card slot4× Zorro III slots1× video slot2× 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 Zorro III slots use 32 bit addressing (Zorro II used 24 bit addressing) but use the same 100 pin slots and are fully backward compatible.The video slot is similar to the A2000's but has a slightly different bracket.The two ISA slots have their power and ground pins activated only. In order to access the slots by the A3000 a BridgeBoard has to be installed. With an installed BridgeBoard one ISA AT compatible card can be used in the remaining slot. Inactive slots can be used for non intelligent cards like TBCs or fan cards.The A3000 has the same 200 pin processor card slot as the one later utilized in the A4000. Processor cards designed for the A4000 may not fit properly if they have a tall heat sink or the SIMM sockets are mounted vertically as the height is limited in the A3000 by the two 3.5" front drive bays.
The A3000 has a vast array of upgrade options, including processor cards, SCSI controllers, retargetable graphics cards, video digitizers, ethernet cards and many other types of expansion.
Interfaces
1× serial DB25 male, RS2321× parallel DB25 female, Centronics1× video DB23 male, analog RGB1× VGA DB15 male, analog RGB2× mouse/game DB9 male2× stereo audio RCA jack1× keyboard 5 pin DIN1× external floppy DB23 female1× internal floppy 34 pin header1× external SCSI DB251× internal SCSI 50 pin header
The built in SCSI host adapter - based around the Western Digital 33C93 SCSI controller - supports up to seven devices connected simultaneously. The controller's configuration is stored in a NVRAM powered by the same battery which the clock is.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.
Motherboard revisionsrev 6.0first production candidateincludes obsolete gate arraysbogus system software in EPROMSillegal sockets for 84 pin PLCCsrev 6.1first production boarda rework wire runs to the FPU from near the FastRAM sectionSCSI termination is mounted directly on the motherboardrev 6.3 (Photo)rev 7.0no SCSI termination is mounted on the motherboard, just sockets for three 8 pin resistor packscannot boot without at least one SCSI device attachedrev 7.1a pull-up is wired to the SCSI select line, which makes booting possible without SCSI devices connectedrev 7.2uses ROM tower instead of EPROMsrev 7.3second production boardthe ROM tower is fastened with wire tiesrev 8.0cosmetic changesrev 8.9third production boardrev 8 inner layers combined with rev 9 outer layersrev 9.0 (Photo)last production boardDaughter board revisionsrev 3.0first production boardrev 6.0 and all previous versions+12V is errantly not connected to the XT expansion slotsrev 6.1 (Photo)+12V is jumpered to the XT slotsrev 7.0created to eliminate the need for the +12V jumper to the XT slotsa mistake in the PCB creation process causes an inner layer short between the +12V & -5V power linesnot shipped to end usersrev 7.1 (Photo)reworked 7.0 to fix the short between the power linesOther components
power supply: 135 W power output2× standard 4 pin power connectors2× mini 4 pin floppy drive power connectorsbattery backed up clock