Bed Heating Errors  

Bed Heating Errors

Hi,

I have had my prebuilt Original Prusa i3 MK2 for a few months, but only recently started using it, beyond the original test print jobs. Initially, it worked perfectly from the factory a few months ago.

Yesterday, I updated everything to the latest firmware and software. I wasn't able to tell for certain which firmware to choose. I chose this one:

1_75mm_MK2-MultiMaterial-RAMBo13a-E3Dv6full

After updating the firmware, the test print job 2Calibration.gcode didn't work quite right (very thin printing), so I removed the print head, cleaned it up using a blowing torch to remove the excess PLA material, then reinstalled it. Everything seemed to work normally after I adjusted the Z-axis down by about -1.32 mm. Then I started my big print job that ran overnight...

This morning, I found part of the print was fine, the other half was a rats nest of misprinted junk. So I cleaned everything up and went to print the 2Calibration.gcode to see what a simple job would do. I noticed the bed temperature wasn't heating up normally, but extremely slowly heating and not reaching full temperature, as shown in the attached.

After a few minutes, the print head reached its full temperature normally, but the bed temp never did and a BED PREHEAT ERROR resulted.

Next, I ran the Selftest, which failed with "Heater/Thermistor Not connected":

Now what? I have run these tests multiple times - same results each time. Since I received my printer prebuilt, I am not familiar with how this thing goes together or what to do next.

Thanks in advance.
Rick