Hey guys,

Just a question about the thermocoupler, is it possible for one to be readings incorrect temps? I say this because we've been having problems recently with prints failing part way through (not consistently at the same layers either) it'll recover then keep doing it throughout the rest of the print, the extruder clicking is there so it's either not gripping the filament or it can't push it through (see this lovely example here).

2015-06-17 17.18.34.jpg

All this is is printed with filament we know works, as it's left over stuff from a few weeks back that printed flawlessly (it has been sealed in an air tight container ever since). Been trawling the web and found many references to 'heat creep' or somthing similar, so thought OK it could be that as we do run it fairly hot (220-230) so tried sticking the temperature down to 215. Nope still happened, even more soon this time. So OK, that sounds like the filament is too cold, the extruder can't physically push it through. Which brings me onto my thermocouple theory.
Is it possible it could be reading a temperature 10-20degrees lower than the actual? I say this because I'm i've just printed this:

2015-06-18 11.24.24.jpg

the first 1/4 up to where it fails, is printed at 230degrees. Thereafter I increased the temperature up to 240, and it actually managed to finish the print at an OK quality, i've tested this twice now, with similar results.

So, could this be a problem with the thermocoupler giving a bad reading? Here's a pic of it (it does look a bit dodgy, like some of the casing has melted away.)
2015-06-17 16.56.40.jpg 2015-06-17 16.28.34.jpg

Of course it could be nothing to do with temperature and be something completely different but I'm at a loss and so any help/guidance would be greatly appreciated, thanks!

I appreciate there's not much info to go on here as it's mainly just a question on whether or not this theory could be correct, I plan on picking up a temp probe in the next day or so to test the temperature of the nozzle/block.