IBM PS/1 User Manual

486SX 20MHz/486SX 25MHz Level 1 (30-Pin Memory
SIMM) System Board Layout
Note: Jumpers are marked in black and should be in positions as shown.
J2 External Battery
J3 Power
J6 Diskette
J7 Parallel Port
Comm A Serial Port
Comm B Serial Port
J8 Hard Disk
J9 Keyboard
J10 Mouse
J11 Hard Disk LED (pin 4 and 5)
Power On LED (pin 1 and 2)
J12 Riser
J15 Video Feature
J16 Display/Signal
J45 30-Pin Memory SIMM Socket Bank 0, 0
J46 30-Pin Memory SIMM Socket Bank 0, 1
J47 30-Pin Memory SIMM Socket Bank 0, 2
J48 30-Pin Memory SIMM Socket Bank 0, 3
J49 30-Pin Memory SIMM Socket Bank 1, 0
J50 30-Pin Memory SIMM Socket Bank 1, 1
J51 30-Pin Memory SIMM Socket Bank 1, 2
J52 30-Pin Memory SIMM Socket Bank 1, 3
JP7 Reset Switch
JP8 Battery Select
JP10 VGA Enable
JP16 PCK Enable
JP23 BIOS Select
JP24 Mouse Enable
JP26 Beeper Enable
U31 Video RAM Socket
U35 Video RAM Socket
U36 Video RAM Socket
U37 Video RAM Socket
U208 486SX Processor
U214 Math Coprocessor Socket
Parts/Test Point Locations
5-9

IBM PS/1 Specifications

General

Processor	Intel 80286 or 80386
Processor Speed	10 MHz (80286)
RAM	1 MB (expandable to 2 MB or more)
Storage	40 MB hard drive
Floppy Drive	3.5" 1.44 MB
Graphics	VGA
Ports	Serial, Parallel, Mouse