AN ACR B737 FLC OPERATING WITH ONE AIR-CONDITIONING AND PRESSURIZATION SYS FOUND THAT THEY WERE UNABLE TO MAINTAIN THE CABIN ALT WHEN THEY TURNED ON THE AIR BLEED ANTI-ICE SYS. THE ALERT SYS AND STANDBY OXYGEN SYS WORKED WELL AND THE FLC DIVERTED AND LANDED. THE FLC FEELS THAT THE OUTSIDE MAINT PERSONNEL ARE UNABLE TO ADEQUATELY SVC THE ACFT.

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LEVEL IN CRUISE FLT AT FL240. IMC IN TSTMS. AUTOPLT AND AUTOTHROTTLES ENGAGED. ENG AND WING ANTI-ICE ON DUE TO ICING CONDITIONS. FLT BEING OPERATED AT LOWER THAN NORMAL ALT DUE TO L AIR-CONDITIONING PACK INOP. AT APPROX XA20Z; (ACFT POS APPROX DEN 060 DEG RADIAL; 150 NM) CABIN ALT HORN SOUNDED. CABIN ALT AT 10000 FT AND CLBING SLOW. NO WARNING OR MASTER CAUTION LIGHTS AT THIS TIME. PLACED PRESSURIZATION IN STANDBY MODE AND SET APPROPRIATE ALT IN STANDBY WINDOW. CABIN ALT CONTINUED TO CLB. CONTACTED ZDV AND INITIATED DSCNT TO 10000 FT. RECEIVED CURRENT ALTIMETER SETTING FROM ZDV. DURING DSCNT; CABIN ALT REACHED 13000 FT. BURNING SMELL PREVAILED IN ACFT. DECLARED EMER AND OBTAINED WX FOR DEN FROM CTR (1/4 MI VISIBILITY; CEILING 100 FT OVCST FOG). CHKED WITH FLT ATTENDANTS; PAX OXYGEN MASK HAD DEPLOYED (OXYGEN GENERATORS ACTIVE). MASTER CAUTION ILLUMINATED FOR PAX OXYGEN LIGHT ON OVERHEAD PANEL. UNABLE TO COMMUNICATE WITH COMPANY DISPATCH OR MAINT DESPITE SEVERAL ATTEMPTS THROUGH COMPANY NETWORK AND COMPANY FREQ. THIS WAS PROBABLY DUE TO ACFT ALT; LOCATION; AND TSTMS. RADIO COM WITH ZDV ALSO POOR. DIVERTED TO DEN. RADIO CONTACT MADE WITH COMPANY DISPATCH APCHING DEN. EXECUTED ILS RWY 35L APCH TO MINIMUMS (RVR APPROX 3000 FT WHICH HAD IMPROVED). NO EMER EQUIP ON GND NECESSARY. LANDED DEN APPROX XH00 AM LCL. PARKED ACFT AND DEPLANED PAX. SWITCHED ACFT AND CONTINUED FLT TO LAS AT XD00Z. CONTRIBUTING FACTORS: ACFT BEING OPERATED WITH AIR-CONDITIONING PACK INOP DUE TO POOR MAINT; LACK OF SPARE PARTS AND SPARE ACFT. (500 MECHS FIRED AND ACFT MAINT OUT-SOURCED). REOCCURRING PROBS WITH INOP AIR-CONDITIONING PACK (PROLONGED FLT OPS DUE TO LOSS OR REVENUE). WEAK PACK (REMAINING OPERATIONAL ONE). INFLT ICING CONDITIONS CONTRIBUTING TO PACK FAILURE OR POSSIBLE OUTFLOW VALVE ICE.