As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT ALTITUDE DISPLAY ON PRESSURIZATION PANEL BLANKS WHEN ALTITUDE IS CHANGED. VERIFIED FLT ALT DISPLAY BLANK. REPLACED CABIN PRESS CONT MODULE REF MM 21 31 02. PERFORMED PRESS SYS GROUND TEST REF MM 21 31 00 700 802 AND SYS MANUAL TEST REF MM 21 31 00 710 801. TESTS OK.