Bed temp failure error - Thermal Runaway Bed and Mintemp bed
Printing frames for corona virus face shields and my MK2.5, with magnetic bed upgrade, stopped with a Thermal Runaway Bed error. Red posted solutions and did all the checks. Thermsistor is properly mounted, wire is intact and plugged into board. Closed door to board and turned the printer on. After heating my extruder was coming up to temp but nothing from the bed and no red light. Then got a MINTEMP BED error. Shut down the printer and did all the same checks over again plus pulled the fuses, all ok - checked with multimeter. Closed it up and now what I get when I turn it on is a blue blinking field on the LCD and no further information. Any suggestions??? I am now down to 1 printer for the shield frames.
I do have a new 13a Rambo board and new LCD available but do not want to do a changeout and blow them if the problem is elsewhere.
RE: Bed temp failure error - Thermal Runaway Bed and Mintemp bed
I've not heard of this one before. I agree, do not replace the main board or LCD yet.
I think this may be one for Prusa Support. It is available 24/7 via live chat from the EShop or via email.
All the best.
Cheers,Dave Jackson"Enthralled Nooby (not so much maybe, ~58 years old)... If 3d printers had been around 40 years ago... "
RE: Bed temp failure error - Thermal Runaway Bed and Mintemp bed
I am also having MIMTEP BED errors on my MK2.5S. After going around in circles looking for non-existent hardware issues, I have found the real culprit. At some point Prusa changed the MINTEP_BED threshold to 30C. This means that if the system reads the bed temperature at or below 30C then the MINTEP BED error is thrown. Well, in my house the ambient temperature is right around 30C, so I always get a MINTEMP BED error. Comparing the source code for a MK3S and a MK2.5S I found that the MINTEP_BED setting for the MK3S is 10C while the MK2.5S is 30C.
I just downloaded the latest 3.9.3 firmware and source code. I have modified the MK2.5S source to reduce the MINTEMP_BED threshold to 20C. As soon as I can get it to compile I will post my results.
BTW. A link is given in the README.MD file to a json file to add to Arduino preferences to add the Rambo boards to the Arduino Boards Manager. Unfortunately, for some reason, the Mini-Rambo 1.3A (MK2) is not in the list of supported boards. The list has only one entry, the Enisy-Rambo (MK3). These are both issues that Prusa needs to fix.