GE MAC 3500

4-40 MAC™ 3500 Resting ECG Analysis System Revision L 
2021337-036
Troubleshooting: CPU PCB Input/Output Signals
Floppy Disk Drive, J13
(for floppy drive — not installed
Pin No. Signal
1 5V Power
2 Index
3 5V Power
4 Drive Select 0
5 5V Power
6 Disk Change
7 NC
8 Media Sense 0
9 Media Sense 1
10 Motor Select 0
11 NC
12 Direction
13 NC
14 Step
15 Ground
16 Write Data
17 Ground
18 Write Gate
19 Ground
20 Track 0
21 Ground
22 Write Protect
23 Ground
24 Read Data
25 Ground
26 Head Select