well that lecroy is a beast
if they would give me one for free i surely woudn't refuse it
. by the way i'm the least qualified person to suggest a repair but i think in those models a common failures are the psu modules , now , again i'm a student and know next to nothing but maybe thats the problem, i'd say open it up and take a look at the frontend and the circuitry than starto to check for rail voltages .....maybe you ll spot some evident failure, hope you can find the fault.
how much did you pay for it ?