As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON AIRCRAFT POWER UP CDU NR 3 SHOWED A BLACK SCREEN. THE MAINTENANCE DIAGNOSTIC COMPUTOR (MDC) LINE REPLACEABLE UNIT (LRU) STATUS INDICATED CODE: CDU 3 FAILED - NO CDU-2OUT. MDC LRU DIAGNOSTICS INDICATED CODE: CDU 3 354 - FAILED. NEW CDU INSTALLED AND SYSTEM FUNCTION CHECKED NORMALLY.