SMT HAS NOSEWHEEL STEERING PROB ON LNDG ROLL; RWY EXCURSION.

Narrative

IT WAS MY FO'S LEG AND LNDG AT MSP. WE WERE LNDG ON RWY 29R. EVERYTHING WAS FINE DURING THE LNDG AND THE START OF THE ROLLOUT. AT 60 KTS; I TOOK CTL OF THE AIRPLANE FROM MY FO AND AT APPROX 35 KTS I TOLD MY FO TO BRING THE SPD LEVERS TO THE LOW POS. ABOUT 2 SECONDS LATER; THE AIRPLANE ABRUPTLY VEERED TO THE R. I APPLIED L RUDDER AND L BRAKE; BUT WAS UNABLE TO REGAIN CTL OF THE AIRPLANE. I DISCONNECTED THE NOSEWHEEL STEERING; BUT COULD NOT KEEP THE AIRPLANE FROM GOING OFF THE R SIDE OF THE RWY. THE AIRPLANE ENDED UP APPROX 50 FT OFF THE RWY IN 3-4 INCHES OF SNOW AT ABOUT A 45 DEG ANGLE. BECAUSE OF THE SLOW SPD; NO ONE WAS HURT; AND THERE WAS NO DAMAGE DONE TO THE AIRPLANE. AFTER INSPECTING THE AIRPLANE THE MECHS DISCOVERED A BROKEN ELECTRICAL WIRE ON THE NOSEWHEEL STEERING. I FOUND OUT LATER THAT DAY THAT THERE ARE 6-8 RPTS A YR ON THIS SAME PROB; SO MINE WAS NOT AN ISOLATED CASE. I DON'T KNOW WHAT WOULD WORK IN FIXING THE PROB; BUT I PERSONALLY THINK THE NOSEWHEEL STEERING SYS ON THE SMT IS A POOR DESIGN.