RepRap extruder temperature problem

[PinballGeorgio]

Hi All,

I have build a reprap printer and for the past days worked flawless. But suddenly have an extruder heating problem.
If I set the target temperature at 190C the temperature stabilizes around the 188C and the extruder won't reach the 190C.
When I choose 220C as target temperature, it stops heating at 215C and so on.
It doesn't matter if I set this in a program or heat the extruder in the printer menu.

Anyone who knows where to start searching? Resetted the printer, didn't help..

[JoeJ]

You probably have bad PID settings. That controls the rate that the extruder will heat up and how it will stabilize. I believe some firmwares like Marlin have an option to auto-tune the PID settings that you could use to fix it.

[PinballGeorgio]

I've done an autotune using the send gcode command and the right code option.
Then I get codes back, but in the extruder option in the printer menu, these values cannot be entered.
They don't exist. Only banbang method or PID method can be set.
The printer is from Zonestar P802M.

[scalci]

also look at the thermister. I had a similar issue, the termister was slightly out of the hotend. Once I placed it properly in my hotend worked 100%

[PinballGeorgio]

Found out that I can enter the PID values in Repetier Host using eprom configuration.
Somewhat better, the target temperature is reached, but fluctuates a lot. This evening try to reseat the thermistor. Hope that helps.
Thanks already for your input!