As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AC RETURNED TO AIRPORT DUE TO PRESSURIZATION PROBLEMS. AC WOULD NOT PRESSURIZE. RESET CIRCUIT BREAKER ON AC. OPS CHECK OK. ALTIMETER STOPPED WORKING. R&R ALTIMETER OPS CHECK GOOD, HSI FROZEN, WOULD NOT MAINTAIN HEADING, COULD NOT DUPLICATE.