AN MD80 DEPARTED LGA AND WAS UNABLE TO PRESSURIZE. THE ACFT DIVERTED AND LANDED AT JFK.

Narrative

I WAS FO AND PNF ON A FLT FROM LGA TO WEST PALM BEACH. I PREFLTED THE EXTERIOR OF THE ACFT AND THE CAPT PREFLTED THE FLT DECK. THE TAXI OUT AND TKOF WERE UNEVENTFUL. SHORTLY AFTER TKOF; WE GOT A 'CABIN ALT' WARNING AT APPROX 10500 FT MSL. THE CAPT LEVELED THE ACFT AT 11000 FT. AFTER LEVELING; I WAS ABLE THEN BEGAN TO WORK ON THE PRESSURIZATION PROB. I ATTEMPTED TO FIX THE PROB BY SELECTING THE #2 AUTO CONTROLLER; BUT TO NO AVAIL; IT DID NOT WORK. THE CAPT THEN MADE A RASH AND QUICK DECISION. HE DECIDED TO DIVERT TO JFK BEFORE WE HAD A CHANCE TO RUN THE CHKLIST OR CHK FOR POPPED CIRCUIT BREAKERS. THE CAPT NEVER CALLED FOR THE CHKLIST BUT I READ IT ANYWAY. WHEN I ASKED HIM IF HE WANTED TO MANUALLY PRESSURIZE HE SAID 'NO.' THIS WOULD NOT FIX THE PROB. AFTER THAT I THEN FOCUSED ON THE QUICK RETURN TO JFK. I THEN ADVISED HIM WE WOULD BE LNDG OVERWT. HE SAID 'THAT'S ALL RIGHT.' THE APCH AND LNDG WERE UNEVENTFUL. MAINT ADVISED US THAT THE CABIN CONTROLLER WAS IN MANUAL THE ENTIRE TIME. THE NIGHT BEFORE; A MAINT CHK WAS RUN ON THE ACFT AND THE CTLR WAS NOT RETURNED TO THE AUTO POS. THE CAPT FAILED TO PREFLT THE CONTROLLER EVEN THOUGH HE READ BACK 'AUTO' ON THE PREFLT CHKLIST. AIRBORNE; I DID NOT CHK IT AFTER THE CAPT SAID HE DID NOT WANT TO MANUALLY PRESSURIZE. THE CHAIN OF EVENTS IS CLR. ALTHOUGH THE CAPT DID NOTHING UNSAFE; HE DID NOT TAKE THE CORRECT COURSE OF ACTION. I KNEW HE SHOULD HAVE ATTEMPTED MANUAL PRESSURIZATION WHICH WOULD HAVE CORRECTED THE PROB; BUT I DID NOT QUESTION THE COMMAND AUTH OF THE CAPT.