IBM Personal System/2 Model 90 XP 486

Type 8590-AJ9
Serial 55-AKA14
Manufacturer IBM United Kingdom Ltd.
Pre-loaded software DOS 4.01
Date June 1992

Physical description

Type Desktop
Dimensions (HxWxD) 140 x 440 x 430 mm
Weight Approx. 11.4 Kg
Drive bays 3 x 3.5" half-height, 1 x 5.25" half-height (all accessible)
Power supply 194 W, 110-220VAC manual voltage switch (9222)

Main board

Chipset/Manufacturer IBM (planar id FF6F)
Bus Micro Channel (MCA) 32-bit
Expansion slots 4 x 32-bit (1 w. video ext., 3 available), one 64-bit for Processor complex (proprietary), two 64-bit for memory cards (proprietary)
Interface FDD (2 units)
Video Integrated 16-bit XGA display adapter (1024x768, 16 colours; 640x480, 256 colours)
Ports PS/2 keyboard, PS/2 mouse, 2 buffered serial (UART 16550A), parallel, XGA


Type Type-1 complex (*)
BIOS IBM, Oct. 1, 1990 (sticker on BIOS chip 28/05/92)
Processor Intel 80486DX-25MHz (32-bit) PGA
Coprocessor Integraded on 486DX
Ext. Cache Optional 256 Kb cache card
Max Memory 64 Mb (8 x 8 Mb) (*)
Memory 2 memory riser cards (dated 9227), each features 4 sockets for 70ns 72-pin SIMMs, parity checked (PS/2 proprietary) (**)
Installed RAM 32 Mb 70ns on riser cards (8 x 4 Mb SIMMs type 71F7010, und.)
SCSI Controller IBM 32-bit PS/2 bus master SCSI adapter/A w. 512 Kb cache (id 8EFF) (sticker 10/06/92)


Diskette drive 1.44 Mb, 3.5" slim-height (Alps DFR723 dated 92-05)
Hard disk Model WDS-3160 (160 Mb) SCSI, 3.5" half-height
2nd Hard disk Model WDS-3160 (160 Mb) SCSI, 3.5" half-height ADDITION


Acquisition Mid-98, collected in a dump together w. other appliances, incl. another PS/2 8590-AJ9 which was demolished
Condition Very good, setup needed
Installed O.S. IBM PC-DOS 5.00 (Italian)
Modifications Removed token-ring adapter, added second hard drive, added 4 memory SIMMs (it had 16 Mb only)
Current status All hw working
Spare parts Almost everything, incl. drives, planar, etc.


(*) Existing processor complex can be changed with a newer one (Type-2, 3, or 4, CPUs up to Pentium-90), supporting up to 256 Mb of RAM

(**) slower 80ns SIMMs can be used instead. With a Type-1 complex SIMMs must be installed in pairs.


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This page was first published on the web on Nov. 11, 2001
Last revised Oct. 26, 2004