As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ACCOMPLISHING T/C #78273000, NR 1 ENG, FMC/CDU INTERROGATION SHOWS SHORT TIME FAULT MSG NBR 73-20341 "THE FMV POSITION SIGNAL IS OUT OF RANGE". GROUNDED - YES. ACCOMPLISHED FIM 73-25 TASK 803 THROUGH STEP F(4). HMU DP0601 RECEPTACLE FAIL RESISTANCE MEASUREMENTS BETWEEN PIN 16 AND 34. REMOVED AND REPLACED NR 1 ENG HMU PER T/C N8473001 AND T/C N8473000. GROUND VERIFICATION CHECKS GOOD. NO LK'S NOTED.