B737-400 CREW HAD AN INTERMITTENT MALFUNCTIONING CARGO COMPARTMENT SMOKE DETECTOR MEL'ED INOP BY A CONTRACT MAINT PROVIDER IN NON COMPLIANCE WITH THE MEL.

Narrative

I WAS JUST NOTIFIED FROM MAINT CTL THAT THEY WERE INVESTIGATING AN MEL FROM A FLT I WAS ON SOME 12 DAYS AGO. HE TOLD ME THEY WOULD SELF-DISCLOSE; AND WANTED MORE INFO. THIS IS WHAT I TOLD HIM. ON THE COPLT'S INITIAL COCKPIT CHK THE SMOKE DETECTOR TEST CHKED CORRECTLY; HOWEVER 10 SECONDS LATER WE GOT A WARNING FOR SMOKE IN THE AFT CARGO AND A BOTTLE DISCHARGE LIGHT. HE WENT TO CHK THE AFT PIT AND I LEFT TO CALL MAINT CTL. HE RPTED THAT THE MIDDLE LIGHT IN THE AFT PIT HAD ILLUMINATED. WE TOLD THE GND HANDLERS TO NOT LOAD THE AFT PIT. A MECH CAME A HALF HR LATER TO TROUBLESHOOT. INITIALLY THE TEST WORKED. AS HE WAS ABOUT TO SIGN OFF THE LOGBOOK WE RECEIVED THE SAME WARNINGS AS EARLIER. HE CHKED THE AFT PIT WITH THE SAME RESULTS. WE CHKED THE MEL BOOK. HE PULLED THE CANON PLUG ON THE SMOKE DETECTOR AND REATTACHED IT. AGAIN; IT WORKED FOR A SHORT PERIOD. HE THEN WENT THROUGH THE PROC IN THE MEL BOOK TO TROUBLESHOOT THE BOTTLE DISCHARGE LIGHT. AS HE WAS FINISHING THE PAPERWORK; WE RECEIVED AN AMENDED RELEASE FOR THE SMOKE DETECTOR INOP. THEN AS WE SHUT THE DOOR TO PUSH BACK; WE RECEIVED AN MEL FOR THE BOTTLE DISCHARGE; WRONGLY ASSUMING THAT THIS WAS CORRECT SINCE HE HAD FOLLOWED A PROC IN THE MEL BOOK. UNFORTUNATELY; THIS ONLY APPLIES TO THE 737-700; -900; AND THREE OF THE -400'S.