What was found
RADIO 2 INOPERABLE COULD NOT HEAR ATC ON COMM 1 OR 2 CAN HEAR/TRANSMIT ON COM 1 IN ALTN MODE ONLY. REMOVED REU PER B737-789 AMM23-51-01-000-801. INSTALLED A SERVICABLE REU, PER B737-789 AMM 23-51-01-000-802 UP TO STEP F. REU INSTALLATION TEST. REU MFG P/N: 5140-1-7, S/N OFF: 2576, S/N ON: 2236. ROTABLE PARTS CHANGE WAS INDICATED-TT NR 1996240 SN OFF 2576 UNIT, ACCY, AUD OFF 29-2351-9-0001 2576 ON 29-2351-9-0001 2236. PERFORMED REU INSTALLATION TEST, PER AMM 23-51-01. OPERATIONS CHECK GOOD.