As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT IN MODERATE RAIN A LOUD SQUEALING SOUND STARTED THEN STOPPED AFTER 5 SECONDS. SHORTLY AFTER AN ARCHING SOUND STARTED COMING FROM FO SPEAKER. WITH IT TURNED OFF A FEW MINUTES LATER A FAINT SMOKE ODOR WAS NOTICED. FOUND FO SPEAKER (8WW) CAUSING NOISE AND SMOKE ODOR. R & R FO SPEAKER IAW AMM 31-53. SPEAKER OPS CKS OK . NO ODORS NOTED. A/C OK FOR SVC. (LP: 7530962, AIRCRAFT WAS GROUNDED)