I am using a MOSFET. Why is my heated bed heating up when set to zero? What should I do?
I haven't modified the firmware from the latest stock version on the Google Drive. All steppers and end stops work correctly in Pronterface. LCD is in agreement with Pronterface too. I haven't checked the hotend yet, but it was obeying the command to stay off. The heat bed was ignoring commands to turn off. It didn't matter if I set the bed to 0C or to 100C -- it just kept heating. I cut power at about 92C.
Would reversing the polarity of the control wires help? Do I need to make a firmware change? Is the MOSFET defective? Just looking for help and ideas so I can get this thing printing! Thanks for any advice!
MOSFET I installed https://www.amazon.com/TriGorilla-Printer-Heating-Controller-Extruder/dp/B01HCVJ3K2
Installation picture (sorry for the wire mess) https://pbs.twimg.com/media/DLLh_zMXkAEFNEP.jpg
LCD showing 65C (and rising) when set to 0C (ambient was around 26C) https://pbs.twimg.com/media/DLLgzx-WsAEwbk9.jpg