So about a month ago I had swapped my stock hotend with a E3DV6 (possibly a knockoff however), and struggled with getting temperatures to stay consistent until finding that I had been sent a 12v heat block. This week I ordered a new E3DV6 24v 30 watt hot end from Matterhackers. Install went fine, except that the block will not heat up past about 140 C. I followed the most recent instructions from E3D exactly - I had made some mistakes with the previous one that I wanted to avoid. The thermistor is not too tight and is reading temps appropriately. I checked the leads and am getting 19.2 ohms resistance for the heater. When the printer is heating, the leads read 24 v. With the previous hot end I did change some settings in the firmware and EEPROM in trying to get the temperatures right, but since then I've installed a fresh firmware (most recent one from Marlin Configs/SV01) with the changes needed for the hot end. Additionally I cleared the EEPROM and verified the settings are matching what is in the firmware. I have tried 3 sets of PID values, one from the SOVOL firmware, one from a forum using the SOVOL w/ E3D, and lastly ran an autotune at only 100 C - made no difference. Any insights? My next idea is to try using the extruder 2 terminals instead, though it appears the power output from the board for extruder 1 is good. EDIT Bed heats fine, so I don't think it is the power supply
So I ended up heating the nozzle without it being in a vise or in a wrench for the hot tightening, and with that modification it was able to heat to 285 no problem. As soon as the wrench touched the hotend, it showed a temperature drop (even with pretty much no force being applied to the block). So I wonder if there is some wiring issue with the thermistor. I was able to tighten it up and get some prints going without issue.
Just fyi anyone else searching this problem, it turns out I had the same issue and I had assembled the j head incorrectly with the first large fin touching the block, there needs to be a gap between the fins and the head. Exact same symptoms as the thread op which is why I found this thread. Mine I believe is a real e3d v6 j head from amazon, but it came with no instructions so I had to do it myself, and didnt realize it. I thought there might be something wrong with the thermistor or resitor, but nope I reassembled it and it heated perfectly.
