What was found
TRANSPONDER QUIT DURING CRUISE FLIGHT. PERFOMED PRELIMINARY INSPECTION. FOUND UNIT TO FIRE UP OK AT FIRST, BUT AFTER AWHILE, UNIT HAD ONLY 50% REPLY. ADJUSTED PRESELECTOR. NO HELP. REPLACED MIXER DIODE CR202. REPAIRED PROBLEM. UNIT QUIT RECEIVING AFTER WARM UP. FOUND PROBLEM TO BEON PRESELECTOR SIDE OF UNIT. REPLACED PRESELECTOR. FOUND UNIT NOT FIRING UP. MOVED COILS IN LOCAL OSCILLATOR. NO HELP.