FO PULLED THE WRONG CIRCUIT BREAKERS IN AN ATTEMPT TO CORRECT A NAV DISPLAY PROB RESULTING IN LOSING THE CAPT'S ATTITUDE INDICATION.

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WHILE AT CRUISE WE HAD A FAILURE OF OUR MAP DISPLAYS. I SWITCHED TO OUR 'ARC' MODE AND CONTINUED FLYING DIRECT TO FAK. I WAS FLYING THE ACFT AND COMMUNICATING WITH ATC WHILE THE FO WORKED OUR PROB. I HEARD HIM MENTION 'AHRS' WHILE I WAS TALKING ON THE RADIO -- BEFORE I KNEW OR COULD STOP HIM HE PULLED 2 CIRCUIT BREAKERS -- B5 AND F2 --IN ; WHAT HE THOUGHT WAS AN ATTEMPT TO 'FIX' OUR PROB. THIS PROMPTLY CAUSED A FAILURE OF MY PFD; WHICH INCLUDES THE ATTITUDE INDICATOR. I HAD TO FLY USING THE STANDBY ATTITUDE INDICATOR FOR APPROX 1 MIN. I WAS IN A L BANK WHEN THIS SELF-INDUCED PROB OCCURRED. I FLEW WINGS LEVEL AND THE ALT VARIED PLUS 290 FT MINUS 100 FT. WE HAD NO PROB OTHER THAN A FMS MAP FAILURE. COMPLETE NAV WAS STILL AVAILABLE. NORMAL FLT WAS STILL AVAILABLE. OUR SELF INDUCED FAILURE COULD HAVE BEEN AVOIDED BY FOLLOWING NORMAL PROCS; READING THE CORRECT ABNORMAL PROCS IN THE BOOK; AND VERIFYING BTWN BOTH OF US BEFORE PULLING 2 CIRCUIT BREAKERS WITHOUT CAUSE. I COULD HAVE FLOWN LEVEL IF I KNEW WHAT WAS GOING TO BE DONE TO ME AND I WASN'T IN A TURN WHEN IT HAPPENED.