As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE AT 39000 FT, CABIN ALTITUDE WARNING WENT OFF, CABIN WAS AT 11K FOLLOWED QRH PROCEDURES AND DECLARED EMERGENCY AND DIVERTED TO FSD. DURING ENGINE BLEED AIR SYSTEM HEALTH CHECK FOUND NR 1 ENGINE BLEED AIR REGULATOR BAD. R & R NR 1 ENGINE BLEED AIR REGULATOR. OPS CHECKS GOOD.