Taz 5 w/ Dual Extruder not reaching temperature

I have a Taz5 on which I’ve installed a Dual Extruder. I’m only using the rear extruder at the moment. It seems like the extruder is slowly degrading in terms of the temperatures it can reach. Last week, attempting to print polycarbonate at 290C, it wouldn’t go over 278C. Today, it’s maxing at 259. This problems seems to be exaggerated when printing from a card. The computer seems to bring it up to temp quicker and closer to the desired setting. Printing off the card, it takes forever to even get to 239C.

Does this seem like hardware? Could the way the software (Simplify3D) or hardware monitors the temperature be responsible?

I’m going to give the front extruder a try and see if the issue repeats with that tool.

The front Extruder has no issue reaching full temp and it does it quickly. Looks like I have a bad rear extruder hot end.

Printing from the front extruder now and it’s a totally different world. Apparently, I’ve been fighting what seems to be a bad extruder for months without realizing it. I’ve been tweaking settings galore to make very marginal prints. I’d even started questioning the quality and shelf life of some of my materials and purchased an expensive drier. I’ll be making a call to Lulzbot Monday.

LinSix, did you get anywhere with this issue? I’m seeing some very similar problems with my dual extruder. T0 gets to temperature okay, but if I run even 30% fan it starts to drop. T1 heats faster and is not affected by the fan at all.