IBM 5155 Manual To Operations page 85

3
Did you receive an 1820 or 1821 error message?
SYSTEM UNIT 100
XX:XX:XX
ERROR EXPANSION UNIT 182X
PRESS ENTER TO CONTINUE
?
YES - Have the expansion unit and its cable
serviced.
NO - Perform the following:
1. Set the Power switches on the system
unit and expansion unit to Off.
2. Set the Power switches on all
external devices to Off.
3. Disconnect the expansion-unit cable
from the system unit.
4. Set the Power switch on the system
unit to On.
5. Go to the next step.
January 1984
Test 200-3