Please assist: Initial Selftest Error - Heater/Thermister Not connected
I recently complete the assembly of my i3 MK3S+ kit and I am getting an error on the Self-Test check: Heater/Thermister Not connected (during the bed check). I have double checked the data connections at the EINSY and the power connections and polarity. The thermister is properly affixed to the heat bed and the wires are not compressed by the zip ties.
I reflashed the 3.9.3 firmware, but that just made it worse. Now I can't access the menu, can't run a factory reset (the menu disappears immediately). It's now stuck perpetually on the temperature status screen. FYI: nothing went wrong with the flash.
I am as a loss as to what to try next, any advice?
Best Answer by Clarmrrsn:
I gather the heater connections are properly tightened both ends?
First thing I would do if this is ok is test the Thermistor with a multimeter.
Prusa Knowledge Base | Multimeter usage (prusa3d.com)
You can also take a hairdryer and blow some hot air at the heatbed above the thermistor, dont go nuts but if you see a temperature change on the bed reading the thermistor is ok.
You can also contact Prusa Tech support via the EShop.
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
I gather the heater connections are properly tightened both ends?
First thing I would do if this is ok is test the Thermistor with a multimeter.
Prusa Knowledge Base | Multimeter usage (prusa3d.com)
You can also take a hairdryer and blow some hot air at the heatbed above the thermistor, dont go nuts but if you see a temperature change on the bed reading the thermistor is ok.
You can also contact Prusa Tech support via the EShop.
Tank you very much!
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
@clarmrrsn
Good idea on the hairdryer. The sensor did respond which I will take as a good sign. I'm still flummoxed by not being able to access any of the menus on the LCD interface, but I will get with the support chat on that. Thanks for your suggestion! If you have any other thoughts to toss my way, I'm all ears (or eyes, as the case may be).
Thanks!
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
@khtt2003
Definately sounds like a duff thermistor, either that or damaged cable.
I am sure prusa chat will sort you out, they are a helpful bunch. 😁
Tank you very much!
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
I don't know. It's sure easy to put the wrong wires on the wrong headers in the einsy board and get this symptom
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
Thanks for your help, folks! eShop support and I were able to isolate the Extruder Thermister as the culprit. Replacement is en route!
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
Could the error message also cause to problems with accessing the menu?
In this topic some one has that problem. He only can't access the menu when I gets an error on start up. Can't access printer settings?
RE: Please assist: Initial Selftest Error - Heater/Thermister Not connected
@baklin
According to Marcin on the support chat, a bad thermister cable can cause the UI to not operate properly (i.e. keep it on the status screen). We'll see if that issue is resolved once the replacement parts arrive.