As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD CARGO FIRE DETECTOR LOOP B WILL NOT TEST. ACFT GROUNDED. AFTER PERFORMING CARGO BAY SMOKE DETECTOR OPS TEST IAW AMM 26-16-00-710-801 AND CEU INSTALLATION TEST IAW AMM 26-16-02-710-801, BEING UNSUCCESSFUL IN DUPLICATING THE FAULT, AND HAVING NO HISTORY OF FAILING, DETERMINED THAT FWD CARGO FIRE DETECTOR LOOP B HAD AN INTERMITTENT FAULT. MOVED FWD CARGO FIRE DETECTOR SELECTOR BACK TO NORMAL POSITION.