IBM 3270 Maintenance Manual page 202

1.
Set the Power switch on the system unit (and
expansion unit, if attached) to Off.
2. Check that the diskette drive connectors are
not damaged and that they are connected
correctly. Replace damaged connectors.
3.
Ensure the diskette assembly mounting
screws are
tight~
4.
Insert your Diagnostics diskette in drive
A.
5. Set the Power switch on the expansion unit
(if attached) and system unit to On and
observe the light-emitting diode (LED) on
drive A.
LED
DID THE LED ON DRIVE A LIGHT BEFORE
THE "BEEP" AT THE END OF THE
POWER-ON· SELF-TEST (POST)?
NO Go to page 3-600-10.
YES
October 1984 3-600;.3