What was found
(CAN) AN AUDIO NOISE PROBLEM HAS BEEN OBSERVED IN SERVICE WITH THE AMS43 TSO DURING ACTIVATION OF HIGH CURRENT DEVICES IN THE A/C. NOISE OF ELECTRICAL MOTORS, & BOOST PUMPS HAS BEEN COUPLED INTO THE AUDIO SYS. AN AMS43 TSO WAS RETESTED TO RTCA DO-160C, IT WAS CONFIRMED THAT THE POWER SUPPLY FILTERING WAS INADEQUATE TO FILTER OUT THE SPECIFIED VOLT RIPPLE FROM THE POWER LIGHT.