<p>My OctPrint and Monoprice Maker Select IIIP (A Wanhao i3 Duplicator Plus clone) were working fine, but suddenly today the hot end won't heat up anymore. I tried disconnecting the OctoPrint USB and resetting the printer power, and it still couldn't heat up the extruder, such as through the filament menu.</p>
<p>But then it got weird.</p>
<p>I left it off for a few hours and turned it on to see if it was getting 12 V to the hot end, and it was heating up again!  So I plugged in the OctopPrint and we're back to square one, the extruder has just been cooling down. I know the thermistor is working, because it's accurately following the temp, such as following the cooldown after the heating stopped working again.</p>
<p>Is it possibly I have a dead hot end and for some reason it temporarily started to work again?  Maybe an intermittent short?</p>
<p>I guess the next step is to open up the base and look at the connector to the motherboard, and or measure for 12 V</p>

[{'answer_id': 18109, 'author': '0scar', 'author_id': 5740, 'author_profile': 'https://3dprinting.stackexchange.com/users/5740', 'pm_score': 2, 'selected': False, 'text': '<p>This has nothing to do with OctoPrint itself, the cause is related to the printer itself, not the print server running the printer.</p>\n<p>This is a pretty commonly seen issue (usually seen at heated beds), this is caused by faulty wires/cables or connectors. This usually happens after a vast period of usage. You should (periodically) check the cables and connectors. You could even test if the heater cartridge works by connecting it directly to the power supply.</p>\n<p>Considering the limited amount of costs involved to replace the heater cartridge, it is preferred to replace the heater with a similar specification heater element (voltage and power).</p>\n'}, {'answer_id': 18110, 'author': 'Perry Webb', 'author_id': 15075, 'author_profile': 'https://3dprinting.stackexchange.com/users/15075', 'pm_score': 0, 'selected': False, 'text': '<p>Measure your heater resistance of the heater in the heater block.  Approximate heater resistances are  4.8 Ω for 12 V 30 W and 3.6 Ω for 12 V 40 W.  See <a href="https://3dprinting.stackexchange.com/questions/10695/proper-hotend-heater-for-reprap-x400-pro-v3">Proper hotend heater for Reprap x400 Pro V3</a></p>\n<p>Note: you could have a heater measuring the correct resistance but have a poor connection in one of the connectors.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/18108', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/2240/']