IBM PS/1 User Manual

Power
Pin Signal Name Pin Signal Name
1 Power Good (+5 V dc) 7 Ground
2 +5 V dc 8 Ground
3 +12 V dc 9 −5 V dc
4 −12 V dc 10 +5 V dc
5 Ground 11 +5 V dc
6 Ground 12 +5 V dc
Diskette
Pin Signal Name I/O Pin Signal Name I/O
18 Direction O
1 Drive 2
19 Ground
2 Density Select O
20 Step O
3 No Connection
21 Ground
4 No Connection
22 Write Data I
5 Ground
23 Ground
6 No Connection
24 Write Enable O
7 Ground
25 Ground
8 Index I
26 Track 0 I
9 Ground
27 Ground
10 Motor Enable 0 O
28 Write Protect I
11 Ground
29 Ground
12 Drive Select 1 O
30 Read Data I
13 Ground
31 Ground
14 Drive Select 0 O
32 Select Head 1 O
15 Ground
33 Ground
16 Motor Enable 1 O
34 Diskette Change I
17 Ground
Note: The diskette drive signal cable for drive A has a twist for the Drive
Select and Motor Enable signals.
Parts/Test Point Locations 5-23

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