As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TWO SEPARATE TIMES A/S WINDOW ON MCP FROZE UP AND COULD NOT TURN AND CHANGE SPEED. ON CLIMB OUT, STUCK AT 315 THEN EVENTUALLY WAS MOVEABLE . AGAIN ON APP STUCK AT 190. HAD TO SELECT VNAV TO SET SPEED BUG. GROUNDED - YES. MCP CHANGE AND ALL TESTS PASSED. REF B737-900 AMM 22-11-34-400-801 / REF ASA L/P 60317195.