As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN PRES WARNING AT FL390. PILOTS STATED THEY SAW A FLUCTUATION OF 2500 FT BUT FELT NO PRESSURE IN EARS.CPC 2 TOOK OVER RIGHT AFTER CPC 1 FAIL. PERFORMED CPC1 OPS CHECK SEVERAL TIMES WITH NO FAILURES. IAW AMM TASK 21-31-34-400-001-A,