As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2122 - ENGINE "SURGE" NOISE INTERMITTENT ABOUT EVERY 5-6 MINUTES DURING CLIMB. RTF PDX MAINTENANCE FOUND NR 1 ENGINE IBV SERVO INOPERATIVE, REMOVED AND REPLACE IBV SERVO COMPLETED GROUND RUNS, ALL OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.