IBM 3270 Maintenance Manual page 372

Your screen should look like the following.
Examine your screen and verify that the
highlighted portion is solid green (there should
be no holes in the highlighted area).
DOES YOUR SCREEN MATCH THE SCREEN
ABOVE?
NO
Replace the programmed symbols adapter.
YES
See Section 5, "Removal/Replacement and
Adjustments. "
Note: The diagnostic detects errors in all
font memory. Replace
th~
adapter only if
the error affects your applications.
October 1984 3-3200-23