As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF POWER WAS SET, MASTER WARNING LIGHT FLICKERED ON MOMENTARILY. NO OTHER LIGHTS NOTED. AFTER AIRBORNE, MASTER WARNING LIGHT STAYED ON BRIEFLY WITH NR 2 PNEUMATIC FAIL LIGHT AND SUMMARY LIGHT ALL PACKS AND BLEEDS WERE OFF. ACCOMPLISHED QRH PROCEEDURE. NR 2 PNEUMATIC PRESSURE WAS 50 PSI. TURNED ON PACK TO BLEED PRESSURE. WOULD NOT GO BELOW 12 PSI. RETURN TO KPHL. MX REMOVED AND REPLACE THE MANIFOLD FAILURE DETECTION CONTROLLER OPS OK.