Have you checked the heater element itself? It should be about 15 ohms for the 115VAC model; if it's open-circuit then that's the problem. The element and the output driver are the most-likely things to fail; why would you think you have "multiple ICs that are bad" ?

If you don't want to buy a new Jobo board(s), you could hook the heater & thermometer up to a commercial PID controller unit; they're pretty cheap.