What was found
AUTOPILOT WHEN IN HEADING SELECT MODE DIVERGES IN ROLL. FOUND ON STEP 7A & 7B AT ROLL COMPUTER BITE CHECK, MM 22-12-0 PG 101-107, FAILED FULL SCALE RIGHT STOP WHEN SELECTING CAPT''S NAVIGATION INFO VIA NAV SELECT BUTTON. AUTOPILOT CONTROL PANEL ROLL COMPUTER BITE TEST OK WHEN USING F/O NAVIGATION INFO. PROBLEM FOLLOWED WHEN SWAPPED CAPT & F/O PDI. REINSTALLED CAPT & F/O PDI TO ORIGINAL POSITIONS. NEED NEW CAPT PDI IND. PLACARD INSTALLED. R&R CAPT PDI. PDI TESTS GOOD PER MM 34-21-0 & AUTOPILOT CKS GOOD PER MM22-10-0.