Did you get a WX FAIL message? Did you cycle the radar? Did you check for tripped CB's? What did your preflight review of enroute WX indicate? Scattered storms or a line? Is there an enroute stop before a line where mx can fix the radar? What does your operations manual suggest to do in that situation?
I had this a few years back, at night over Atlanta. I gave the aircraft to the FO and told him to fly where he could see the lights on the ground so we would avoid over flying a cell (of course notifying ATC of our problem) . ATC was as helpful as possible - their radars aren't set to specifically look for storms but can help. Other aircraft were in the area which also provided more info. Dispatch conferenced in with system maintenance - there was no reset for the radar. Our aircraft are equipped with internet - it was not yet authorized for cockpit use. None the less, I purchased internet and loaded up our weather app. and continuously plotted our position (new WX app does that automatically) . That coupled with dispatch info, ATC info and other aircraft info provided us with a comprehensive picture which allowed us to pick our way in the clear through the scattered thunderstorms.
Had it been a line of storms I would have reversed course and diverted if circumnavigation would not have been an option. Yeah that problem is a gut check, that's why you get paid the big bucks...