max bed temp

Error reading max bed temp please reset. It started with a jammed nozzle, then replaced . then to a extruder gear slipping because of a jam about 40 mins into a print…Got a creality motor and gear and now max bed temp please reset. I have replaced the entire bed with new, a new aluminum extruder gear, new nozzle new hot end. when I turn the machine on it turns on and goes immediately to the hot bed error. The machine is a year old not much printing until late with rc car parts all from thingy verse. I am new to this but right now besides a new mother board I am thinking of a boat anchor. HELP Thanks in advance Skip Florid