Hi,
it happened for the second time this week. After connecting my hot bed thermistor the marlin firmware shuted down due to an "min temp" error. Both temp values for hot end end hot bed showed 0 deg. I disconnected anything, but the error remains. I changed the atmega board end everything worked fine until I connected the hot bed thermistor. Afterwords the mailfunction happened again. It seems as the atmega board has defected a-ports. But I do not understand how it could happen. I could masure something like 120 kOhms on both thermistors. There is no visible short in the wires. Its realy strange.
Is it possible to check the ports? As it seems its a13 and a14. I may use an oscilloscope but I am not sure how the analog ports work.
Is it possible to destroy them without destroing the whole processor or board?
What could cause the mailfunction? Maybe there is something wrong with the ramps?
Any help is appraciated. I fear if I buy an new board it will happen again.
Thanks Jakub
