As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPTAINS YOKE PUSH TO TALK SWITCH INOP ONLY ON HF-1. WORK SO ON OTHER RADIOS. HF-1 RESPONDS NORMALLY FROM CAPTAIN HAND HELD MIC AS WELL FROM FO'S SIDE. GROUNDED - YES. RESET HF-1 AND PERFORMED OPERATIONAL TEST IAW B737-800 AMM 23-11-00. OPS CHECK OK. PTT OPS CHECK OK. COULD NOT DUPLICATE FAULT.