Earlier this year I purchased a Prusa rep-rap I3 printer for a school project. After some initial trouble, I got it working just fine. However recently the bed stopped heating. This happened after an overnight print, the second it had completed. The display is showing room temperature for the bed, and I do not think that the sensor is the problem, as I see it changing up or down a degree occasional (I assume that this it just reading changes in room temp). One thing I did notice is a small amount of build up of the fluid that I use to clean the bed on the exposed contacts to the heated bed, however it was not connecting the contacts to anything else, so I don’t think that anything has shorted (?).
Anyways, any help would be much appreciated. Thanks in advance.
The thermistor has died: simple enough to check, if you know what type is you can get the datasheet and use a multimeter to test it or B place a cup of boiling water on top of the sensor and see if the temp rises in the controller interface.
Power supply failure: don’t know what setup you are using but it is possible for mixed voltage setups again simple enough to test with a multimeter. I’ll assume your using a ramps controller and a single 12v supply if everything else still works then it’s not the supply.
The bed has failed: the heating element on the bed may have failed, to test use a multimeter, test for voltage at the bed side of the cable, if there is no voltage you may have a break in your cable or … see next.
The transistor has blown on the controller board: this can happen quite easily, it’s a bit harder to check if you don’t know a little about electronics it will also depend on your controller board… some have a led that blinks coming from the transistor if it’s not on then it could be a blown transistor.
