Hello,
I recently buy a second hand K8400, fitted with an Mk3 heating bed.
Everything was right and I’ve printed succesfully some PLA small parts.
Two days ago, I manualy drived (with the PC control screen of course) the printing head to the forward right corner of the printing area, to check what’s the clearance for installing a small control cam.
After completing measurement, I used the LCD “autohome” control to send the printing head to his initial position. Unfortunately, during his travel back to home, the printing head hit one of the paperclip maintaining the heating bed glass.
The paperclip didn’t get out immediatly and I’ve heard a “clac clac clac” noise (I suppose that some teeths of the belt jumped) but mainly, when I tried to launch a new print, an error message comes on screen: “Printer stopped due to error. Fix problem and use M999 to restart (Temperature is reset, set it after restarting)”. On the printer’s LCD screen, it was specified: Err: MINTEMP.
First I tried to shutdown everything and to power on again: no changes.
Then I removed the printing head and I noticed that the isolating sleeve around the thermistor lower cable was damaged. I supposed that the nude wire had touched the brass heating block. This thermistor seems not being an original one, but before the incident, it was working. I’ve removed the rest of the isolating sleeve, and the thermistor seems not burned. Is it possible to make a measurement of this component?
Having a spare original thermistor, I’ve installed this one properly, following the Vertex assembly notice.
The error message is still on the PC screen, but on the LCD screen, now it appears “Err: MAXTEMP”.
I tried to reload the firmware (M1.V1.4. H1) above the older one, doing this with Arduino 1.6.4. (Veretex recommend to use Arduino 1.6.0. to proceed, but is this really important?)
During this reloading, I found that the shunt was already installed on the board. Is it recommanded or not to let it in place after the end of loading?
Anyway, I didn’t see nothing happening on the LCD screen during the firmware loading, nor when I followed the next steps (restore failsafe and store memory of the l’EEPROM).
After two days of various searchs on the Web, I’m convinced that problem comes from temperatures readings.
All the more so as in the lower control bar of Repetier, reported temperatures are Extruder 0,0°/Off et Heating bed 0,0°/Off while when everything worked, it was the room temperature who was reported.
Is it possible that the new thermistor is faulty? (I’ve read that someones replaced the original part with other ones more precise and improved the tthermal conductivity with special paste).
Is it possible that a shortcut between the thermistor wire and the brass heating block damaged the main control board?
How to enter the code M999 when the problem will be fixed?
Sorry for the language faults, and thanks a lot for your answers.