IBM 5150 Hardware Maintenance Manual page 115

Check the Diskette Drive Power connector for the voltages
listed in the table below.
Diskette Drive Power Connector
Min Vdc Max Vdc -Lead +Lead
+4.8 +5.25
2
4
+11.52 +12.60
3
1
ARE THE VOLTAGES WITHIN THE TOLERANCES
SHOWN IN THE TABLE?
NO
Go to PIC 020, "Power."
YES
600-20