It seems that the temp sensor is reading abnormal or it is broken.
Have you tried to flash it? If not then try it first then try to test the hashboard one by one
Also, a little bit of research here on the forum will bring you here
https://bitcointalk.org/index.php?topic=5244120.0Reading that would help you to get rid of the sensor problem.
I was thinking of trying the SD card / flashing but wasn't 100% sure how to do it and didn't want to mess up the rig.
Thanks for the link, I'll try to do this today and see if it works.