I’ve seen lots of temperature problems in the forums. Yet not exactly this one:
I’m having a strange temp graph. Everything is fine for some time. But then the extruder temp rises very high. And the software stops working.
Any ideas anyone, please? 
[quote=“eboreg”]I’ve seen lots of temperature problems in the forums. Yet not exactly this one:
I’m having a strange temp graph. Everything is fine for some time. But then the extruder temp rises very high. And the software stops working.
Any ideas anyone, please? 
[/quote]
I did not see this behavior before… You say this happens over time? You can work for some time and then it happens? Then I would say it’s a software problem… Is the red line a setpoint or a actual temperature? In case of the first your PID parameters are tripping for some reason. In case of the second: I doubt the temperature rises up to 500 °C 
Did you try resetting the settings/re-installing Repetier?
You should check the thermistor wiring on the extruder.
It looks like the wires maybe shorting in the heater block.
[quote=“Wrong Way”]You should check the thermistor wiring on the extruder.
It looks like the wires maybe shorting in the heater block.[/quote]
You were right.
I’ve rewired the thermistor and it works perfectly now.
I presume the end of the thermistor wire pierced the textile cover. Or the tin solder.
ps: now printing my first object, the casing from the tutorial. yay!!
Excellent.
Glad to hear it’s working.
Enjoy your printer.