IBM RT PC 10 Hardware Maintenance And Service page 156

22x
I/O Channel Memory Error
Additional Tests: None
Removal Procedure: An error occurred in memory attached to the
I/O channel between memory addresses
080000 and 09FFFF. This area of memory is
not supported as I/O channel memory in the
IBM RT PC System. Check for non-IBM
memory installed.
Repair Checkout: Run the System Checkout.
23x
FRU: Personal Computer AT Serial/Parallel Adapter
Additional Tests: Run the Personal Computer AT Serial/Parallel
Adapter checkout.
Removal Procedure: See "Adapter Removal" on page 4-16.
Repair Checkout: Run the Personal Computer AT Serial/Parallel
Adapter Checkout.
Problem Isolation Charts 3-111