Aargh! Thermal Runaway then SMOKE  

Aargh! Thermal Runaway then SMOKE

Got my shiny new printer on Thursday. I managed to print a couple of small items (a bookmark and the PRUSA Logo). I wanted to try something a bit bigger so I loaded up Cura and tried to print a 100mm diameter coaster. I was watching it fairly closely and noticed that the nozzle temperature seemd to be jumping about all over the place. Anyway the print still seemed to be progressing ok. With about 10-15 minutes to the end the print just stopped and the message Thermal Runaway was on the LCD display. I didn't have time to check it out properly, so I left it and returned to it on Friday. I again wanted to print something simple so I loaded up the Tree Frog on the SD card and set it away. The print bed heated up normally but when it switched to heating the nozzle, I noticed that the temperature did not move from 26/27 degrees on the LCD display and then smoke started coming from the extruder housing.

I immediately switched it off.

After a while I ran the self test and it said everything was fine, but the nozzle temperature does not change when I set it to heat up then I get more smoke if I leave it to get really hot.

Any idea what has gone wrong? It's a bit disappointing for it to malfunction after only a couple of days.

Please help.

Regards,

Stuart.