[SOLVED] on [EDIT 3]
I just finished changing my i3 Mega's PTFE tube and brass nozzle, reassembled it, always taking care not to damage the heating element and thermistor wires. Then I check the temperature and it was cooling down, despite the set temperature being higher (210 ºC). I turned it off, let it cool down and turned it back on. I set it again to 210 ºC and it only reaches about 135 ºC-140 ºC, not going over it. So I change the heating element and thermistor for fresh new ones (original ones, that came with the printer) and the same behavior takes place: not heating up beyond 140 ºC.
Any ideas on why this is happening or how to fix it? I checked the connectors and they all seem to be fine. Cooling fans run normally as well.
Printer: Anycubic i3 MEGA. All stock parts, except the new nozzle (standard brass nozzle) and the PTFE tube (a blue one with 1.9 mm internal diameter). I'm setting the temperatures through the printer's interface, as I have always done.
I did check some stuff with the multimeter and what I got is that:
- The cables leading to the print head are fine;
- The heating element's voltage is correct and the MOSFET seems to be working fine both by checking the voltage and from the LED that lights up when it is sending current to the HE;
- The resistance of the HE is correct as well;
Form that, I am guessing the problem is the current fed to the HE. Later today I will try to heat both the nozzle and the bed to the (safe) max temperatures and see if the bed heating is problematic too. If so, the problem should be related to current.
If anyone has any other ideas, they are appreciated! :)
Heating up the print bed and the hotend at the same time didn't affect the bed at all. It heated up at the same pace as usual. Since the cables are fine, it shouldn't be a problem related to the power supply.
So I'm gessing the problem is the motherboard (Trigorilla 1.1). It didn't seem to have any burned components at a glance but I'm gonna check with a multimeter.
Turns out I messed up the heatbreaker, so the heatsink was cooling the hotend way too much... This is one way of learning I need to be careful with the heatbreaker, I guess. I'll leave a solution here for the newbies like me that end up in a similar situation.