What was found
WE SUCCESSFULLY LOGGED ON TO CPDLC ON THE GROUND IN PDX. AUTOMATIC TRANSFER FROM KUSA TO KZAK WAS SUCCESSFUL. RECEIVED AUTOMATED MESSAGE TO CONFIRM CPDLC LINK. USED ACARS TO OBTAIN WEATHER AND LANDING DATA BUT DIDN'T RECEIVE ANY INFO. ACARS DISPLAYED CONTINUALLY MESSAGE "HF IN PROG" EVENTUALLY WE RECEIVED MESSAGE "DATA LINK LOST" AND ON ATC LOGON/STATUS 1/2 DATA LINK SHOED "NO COMM" AFTER AWHILE WE SAW "ATC COM TERMINATED" WE LOGGED BACK ON AND IT SEEMED SUCCESSFUL BUT ARINC RELAYED FROM KZAK THEY WERE NOT GETTING POSITION REPORTS. EVENTUALLY ACARS WENT "NO COMM" HF2 AND VHF3 WERE BOTH IN DATA. GROUNDED - YES. ON DEFERRAL.