As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 INVERTER FAILED ON CLIMBOUT. LEFT MICROPHONE STUCK IN TRANSMIT POSTION. PILOT DESENDED BELOW 18,0000 AND SQUAWKED 7600. PILOT REPORTED HSI EFIS SCREEN FAILED. PILOTS SIDE HSI WAS SWITCHED TO DISPLAY ON MFD. LANDING WAS MADE UNEVENTFUL. INSTALLED INVERTER AFTER REPAIR, OPS CHECKED GOOD. INSTALLED NEW PILOTS SIDE HAND MICROPHONE, OPS CHECKED GOOD. RERACKED DPU FOR PILOTS SIDE EFIS. REPLACED DPU COOLING FAN FUSE. OPS CHECKED GOOD. FLIGHT CHECKED GOOD.