As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT 24,000 FEET ALTITUDE COULD NOT MAINTAIN PRESSURIZATION. LESS THAN 500 FPM CABIN ALTITUDE CLIMB. DECENDED TO 15,000 FEET AND COULD ONLY MAINTAIN 9,000 FEET CABIN ALTITUDE. *S/D* THE RADIO RACK COOLING VALVE WAS STUCK OPEN. REPLACED VALVE.