As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU GENERATOR REQUIRED SEVERAL ATTEMPTS BEFORE IT PROVIDED ELECTRICAL POWER. APU WAS RUNNING AND BLUE APU GEN OFF BUS ILLUMINATED BUT VOLT AND FREQUENCY METER INDICATED 0 VOLTS. GROUNDED - YES. REMOVED AND REPLACED START CONVERTER UNIT REF B737-800 AMM 49-41-61, OPS CHECK NORMAL PER SAME.