As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT HAS SMOKE IN CABIN. INSPECTED AND DETERMINED TO BE FROM AUXILIARY POWER UNIT. COMPLIED WITH BLEED AIR BLOW OUT AND PLACED APU ON MEL. AIRCRAFT RETURNED TO SERVICE. MEL CLEARED ON 5/10/97 BY REPLACING APU, OPERATIONAL CHECK GOOD.