IBM Personal Computer XT Manual To Operations page 87

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 - Do the following:
1. Set the Power switches on the system
unit and expansion unit to Off.
2. Set the Power switches on all
attached 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.
April 1984
Test 200-3