What was found
PDX-ATB OF F500 DUE TO MULTIPLE CIRCUIT BREAKERS POPPED. AIRCRAFT RETURNED TO PDX. PDX MAINTENANCE INSPECTED AND FOUND A FAILURE OF THE WIRE BUNDLE INSULATION AT BS 410, WL 203, RBL 58 (BEHIND LINER IN FORWARD CARGO COMPARTMENT AFT OF E/E BULKHEAD AND FORWARD OF THE FORWARD CARGO DOOR). MAINTENANCE REPLACED THE WIRING ON A/C 772. THERE WERE NO SYSTEM PROBLEMS FOUND DURING THE REPAIR OR SUBSEQUENT SYSTEM CHECKS THAT WOULD HAVE CAUSED THE WIRING TO OVERLOAD. EO 2400-01047 WAS ACCOMPLISHED ON THE 737-400 FLEET WITH NO EVIDENT SYSTEM FINDINGS. BASED ON THESE FINDINGS IT WOULD INDICATE THAT THE DISCREPANCY ON A/C 772 WAS AN ISOLATED OCCURANCE OF WIRE CHAFING. (M)