As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT ALTITUDE THE CABIN PRESSURE WARNING LIGHT ILLUMINATED AND THE RATE OF CLIMB FOR THE CABIN ALTITUDE WAS 4000' ASCENDING. PILOT'S MADE AN EMERGENCY DECEND TO 12,000 FT. BACK AT THE STATION THE FAULT LIGHT ON THE SELECTOR PANEL REMAINS ILLUMINATED INDICATING A VOLTAGE SUPPLY PROBLEM TO THE CONTROLLER.