IBM 3270 Maintenance Manual page 151

The failing module is probably in one of the
banks that has not yet had a module replaced.
HAVE YOU REPLACED THE FAILING
MODULE IN EACH OF THE FOUR BANKS?
NO
Go to page 3-200-24.
YES Replace the 64/256KB Memory Expansion
Option. Remove all 64K modules from the
failing adapter and install them on the
new adapter. See Section 5,
"Removal/Replacement and Adjustments."
Mter you have installed all the modules
on the new adapter, run the diagnostics
again (see page 3-200-55).
3-200-26 Maintenance Information