IBM Personal System/2 Model 40 SX

Machine type 8540-045
Serial 55-MXT77
Manufacturer IBM Corp., United Kingdom
Date September 1991

Physical description

Type Desktop (may be converted to Floor standing) (11 SEP 1991 print inside top cvr, 7 AUG 1991 print on drives tray, cables 10/91 or 11/91)
Dimensions (HxWxD) 169 x 440 x 394 mm
Weight 12.6 Kg
Drive bays 1 x 3.5", 3 x 5.25", all accessible
Power supply 197 W, 110/220VAC switchable (9135)

Main board

BIOS IBM, Sept. 23, 1991 (26 Kb)
Clock 20 Mhz, 0-2 wait states
Processor Intel 80386SX (32-bit) PQFP
Coprocessor Socket for optional i80387
Memory 3 sockets for 85ns 72-pin SIMMs (PS/2 type), parity checked (accept faster 70ns SIMMs)
Max on system board 16 Mb (about 15,5 Mb usable)
Bus AT 16-bit 
Expansion slots 5 (AT 16-bit), on riser card
Video Integrated 16-bit VGA display adapter
Interface HDD (2 units type IDE/ATAPI), FDD (2 units)
Ports PS/2 keyboard, PS/2 mouse, serial (UART 16450), parallel, VGA


Installed RAM 3 x 4 Mb 70ns SIMMs (two have 92-14)
Ethernet SMC 8003EP (03-93) ADDITION


Diskette drive 1.44Mb, 3.5" slim (Alps DFP723, 91-15)
Hard disk Maxtor 7080AI (80 Mb) IDE/ATA, 3.5" slim (28 JUL 1991)


Acquisition Mid-98, collected in a dump together w. other appliances (incl. another PS/2 40 which was demolished to get spare parts)
Condition Very good
Installed O.S. IBM PC-DOS 5.00 (Italian)
Modifications Added one memory SIMM and ethernet card
Current status All hw working
Spare parts Almost everything, incl. drives, planar, etc.


Back to Systems Listing
Back to PCs Main Page
Back to Home page

This page was first published on the web on Nov. 11, 2001
Last revised May 24, 2004