What was found
WHEN SLATS EXTENDED ON DESCENT, UNABLE TO CHANGE STABILIZER TRIM, ELECTRICAL OR MANUALLY. CHANGED A/P NO HELP. WHEN A/P ENGAGED, A STAB OUT OF TRIM DEU WARNING WAS DISPLAYED. CONFIG PAGE SHOWED 1.0 ANU AND AFT PRESSURE NEEDED TO CONTROL ALTITUDE. LANDING AT FFO NORMAL AT 35 DEGREES, FLAPS WITH HIGHER THAN NORMAL BACK PRESSURE NEEDED FOR APPROACH. ADDITIONAL PARTS INFO DAL 27001480 S/N OFF UNKNOWN. DAL 27001511 S/N OFF DCA 708. DAL 270201800 NO S/N.