What was found
AIRCRAFT DIVERTED, CAPT HSI HEADING FLAG DISPLAY INTERMITTENTLY, HEADING IS BAD AND HEADING SLEW BUG IS ERRATIC, PLACING COMPASS SWITCH TO BOTH ON NR 2 DOES NOT FIX THE PROBLEM. AIRCRAFT MADE AN UNEVENTFUL LANDING. REMOVED AND REPLACED CAPT HSI PER BOEING MM AND TIGHTENED LOOSE WIRE ON TRANSFER SWITCH, OPS OK AT THIS TIME.