A couple of weeks ago I have successfully built a 3D Printer and Printed an XYZ Calibration Cube with ABS material at bed temperature 80 °C.

Next Day I tried bed heating at bed temperature 80 °C,

Screen is blank

and it's not heating at all and showing Following error.

Bed Heating Failed Printer Halted Please Reset

Specification board

I use a RAMPS 1.4 running Marlin 1.1.X


I searched on Google and tried possible solutions but they are not working.

  1. I changed the thermistor and nothing happened, the old thermistor is also showing the same temperature.
  2. I connected 12V Supply Positive to SMPS (Switched-Mode Power Supply) and Negative to RAMPS 1.4 and not working
  3. I checked the Voltage at heat bed it's showing zero in spite connecting to SMPS

Please let me know how can I fix the problem?

I have blank image after pressing 80 °C

  • $\begingroup$ I have installed Marlin 1.1.x firmware. When It's powdered it'll display properly but when I select Bed Heating Option It becomes like a shown in the image and after 30 to 50 seconds later it displays message Bed Heating Failed Printer Halted Please Reset Except Bed heating everything working fine $\endgroup$ Feb 4, 2019 at 18:47
  • 1
    $\begingroup$ What happens if you set Bed Temp to, say, 40 Degrees C? Does it warm at all before throwing an error? $\endgroup$ Feb 4, 2019 at 20:25
  • $\begingroup$ No, Warming. The LCD Temperature won't change at all from Room Temperature i.e 25 Degrees Celcius. $\endgroup$ Feb 5, 2019 at 1:56
  • $\begingroup$ Why not attach your PSU directly to the bed, will it warm up? If it does the bed is working then check cables, connectors of the setup. $\endgroup$
    – 0scar
    Feb 5, 2019 at 11:00
  • $\begingroup$ When I connect Heated Bed directly to SMPS it's working but when I connect it to RAMPS board it's not working and the screen is becoming blank $\endgroup$ Feb 12, 2019 at 7:39

2 Answers 2


Check that your heated bed is still working:

  • Measure the resistance of your heated bed. It depends an the power rating of the bed, but 12V beds usually have values <3 Ohms. That's hard to measure for cheap multimeters, but you just need to check that it's not MOhms which would indicate a broken heated bed.
  • Your heated bed could also have a short. That's hard to measure, as <3Ohms are already 'almost a short'. You'll only notice because your bed will not get warm, but the wires, connectors and elements on the RAMPS will get even hotter. Marlin should detect this and switch off after a few seconds.
  • Check your thermistor. Seems you already did that.
  • Check your RAMPS by measuring the voltage on the bed connector while setting the bed to heat up. You should see 12V, at least in the frist few seconds.
  • $\begingroup$ Heated Bed is working. when I connect directly to 12V SMPS but it's not working when I connect it to RAMPS 1. 4 $\endgroup$ Feb 8, 2019 at 1:49

I've just been reading 3D Printing Failures: 2020 Edition by Sean Arandy and David Feeney -- one of the things they really harp on is that the high current connectors on the RAMPS board for the bed heat are grossly under-rated -- that is, they're connectors rated for about 4-5 A, while the bed needs to draw about twice that to heat a rated power level. Their recommendation is to switch this connector on the RAMPS board for one rated at a minimum of 16 A to ensure it has a safety margin over the most current a 12V bed heater will draw.

If you use an e-reader, you may want to consider downloading this book -- it's only ten dollars for Kindle (also available on Kindle Unlimited), or twenty for a paper copy, and to my eye, it's worth having.


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