B737-200 LOST MOST OF THE CAPT'S INSTS. CREW DID NOT KNOW THAT THE CIRCUIT BREAKER FOR THE #1 NAV BUS HAD TRIPPED. IT WAS DUSK AND THEY HAD CHS IN SIGHT SO THEY MADE AN EMER DSCNT AND LANDED THERE. FO FLEW BECAUSE CAPT HAD LOST SO MANY INSTS.

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FLT PROCEEDING NORMALLY. THEN AUTOPLT DISENGAGED AND MULTIPLE CTL/PERFORMANCE/NAV INSTS FAILED. STANDBY PWR DID NOT ENGAGE AUTOMATICALLY; NOR WOULD IT MANUALLY. APU WOULD NOT START (FL330 OR FL210). SINCE CAPT'S INSTS WERE INOP; FO FLEW DSCNT; APCH; AND LNDG. DECLARED EMER WITH ZJX AND DIVERTED TO CHS; WHICH WAS VISIBLE FROM ALT. APCH AND LNDG UNEVENTFUL. TAXIED TO GATE. EMER AND NORMAL CHKLISTS WERE ACCOMPLISHED; HOWEVER; EMER CHKLISTS WOULD NOT RECOVER PWR TO ANY SYS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE APPARENT PRIMARY CAUSE OF THE PROB WAS A TRIPPED 35 AMP CIRCUIT BREAKER THAT PWRED THE #1 NAV BUS. NOT ONLY WAS ALL THE CAPT'S NAV GEAR INOP; BUT THE CABIN OUTFLOW VALVE LOCKED IN POS MAKING CABIN PRESSURE CTL IMPOSSIBLE. RPTR ADDED THAT THIS IS THE THIRD ACFT WITH HIS AIRLINE TO HAVE THIS FAILURE. ONE WAS ON THE GND AND THE OTHER WAS JUST ABOUT TO LAND. HE HEARD A RUMOR THAT THE MANUFACTURER PLANS TO FIX THE PROB BY INSTALLING A HIGHER AMPERAGE CIRCUIT BREAKER FOR THE BUS. CIRCUIT BREAKER WAS HIDDEN BEHIND A GARBAGE BAG.