What was found
ON POWER UP C/BS F12 & F11 POPPED. TRIED RESETTING & POWERING UP ON INVERTER NR 2 THEN F11 POPPED. CAPT'S SIDE AVIONICS FAILED TO INITALIZE. AFTER RESETTING ALL BREAKERS & RESETTING PWR EVEN F11 & F12 STAYED IN. MAINTENANCE REMOVED AND REPLACED NR 1 AHRS COMPUTER, ALL CKS GOOD IAW SAAB MM CH 34-20. S/N OFF 2846, P/N OFF 622-6190-113, S/N ON 2247, P/N ON 622-6190-113.