Solved Bed temp shows wrong temp between 66 and 67 degrees

I'm really stumped. The temperature in my room is 24 degrees. I have a Robo 3Dr1+ and had to change the boards. Now the temp for the extruder works but the heat bed shows it is 66-67 degrees and stays fixed even the real temp is 24 degrees. It is plugged into T1 and if I switch it to T0 where the extruder is it works. I also did a quick test by shorting the pins on T1 and it shows 368 degrees showing that the port (T1) recognizes the change. I tried another thermistor just for fun and it doesn't work any differently. When I plug in the extruder into T1 it doesn't display correctly either. My settings in configuration.h are:

#define TEMP_SENSOR_0 1 //robo
#define TEMP_SENSOR_1 0
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 1 //robo

So it seems that the wire is good, the thermistor is good, the board is good (might not recognize anything other than 66-67 or a complete short). I am stumped any ideas?

 

Thanks Mark,

I shorted the pins and they changed does that change your response? I'm thinking it is a bad board myself but I would think it would just not sense anything. It did register the short across the pins.

 

Well thanks to the great response from Robo 3D I have a new board but guess what...The temperature is still the same 67-68 degrees. No difference. So I grabbed my DuetWifi and another generic setup Arduino and Ramps and connected the wires to them and they all register the correct temperatures. Is there anywhere that could make this report wrong? Software or hardware? I was told not but obviously if the others get the correct temperatures then the wire, heater, thermistor are all OK. I would doubt that 2 boards from Robo 3D could both be bad with the same issues.

 

Well now it is even better. I took another Ramps Board and Arduino connected it and the temps are correct. I took the Ramps and put it on the Robo 3D Arduino board and it didn't work. So I put the Ramps board from Robo 3D on top of a different Arduino that I just ordered and it works. So it looks like the Ramps board is OK but the Arduino is the problem. That to me doesn't make any sense. Now I guess I need to discuss that with Robo 3D guys and see what could cause that and maybe why. I am running the same software on all of the boards and supposedly they are the same Arduino Mega 2560.

Thanks everyone for your help and ideas!!!

 

Can you use another Arduino Mega 2560 to power the Ramps board and the Robo3dR1+ or are there some issues? I only have been using the USB part of the system so far (connected to my PC). If I have to wait for a part from Robo then it would be nice to fix it temporarily so I can get some things done.

 

Well got the new Arduino from Robo and that was it!!! The board itself was the problem.