As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE GAIN AND TILT KNOBS ON THE RADAR CONTROL PANEL FOR THE CAPTAIN'S SIDE ARE JAMMED TOGETHER AND DO NOT FUNCTION PROPERLY. ACFT GROUNDED. GAIN AND TILT KNOBS STUCK TOGETHER DUE TO GRIME AND DIRT. CLEANED KNOBS AND CHECKED SYSTEM IAW AMM 34-43-00, GROUND FUNCTIONAL TEST GOOD.