IBM 5150 Hardware Maintenance Manual page 105

Check the Diskette Drive Power connector on Diskette Drive
"A" for the voltages listed in the chart 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
600-10