What would cause erratic hot end fluctuations to the cold side of things? Temp set at 200c, temps going to 202c and dropping to 168ish, then back up. Cura calling out min temp protection. Connections are good, no signs of connection issues, this is the end of my night and my next step after work tomarow is to replace the whole hot end, then test the components. The temp read out stayed consitionant through cool down, I’m going with heater failure unless anybody has better idea?
Check your thermistor. Let it set till it’s room temp, then measure the resistance. It should be at around 100kΩ at 25°C if you’re using a normal NTC thermistor.
@_Spice LCD read out says 24c and thermister ohms is 100.4 ! It gave consistent readout on cool doun
Do you have a multimeter? You might be able to check the voltage on the heating element: it should be 12v while the nozzle is heating (and kinda random once it’s at temp, depending on how good your multimeter is.) I also suspect the thermistor’s more likely the problem.
@John_Bump thermister checks out. I can read body temp with ohm meter! Base at 24c is at 100.4 ohms. The heater measures 0 . Will cura settings cause this kind of problem? I did get aggressive with my settings? I’m a car guy? When you run lean, you go rich and find the middle, I did have a couple yellow boxes?
I don’t think the settings should matter. The heat control is a software loop that you probably can’t easily alter, so all that determines its stability is the thermistor, by which I mean, if the heater doesn’t work, the thermistor will sense that and turn the heat control on full until the heater gets up to temperature, which it won’t ever do if it’s broken. It sounds like you have an intermittent connection somewhere, and I’m betting it’s more likely thermistor than heater. I don’t know how to do this in cura but in some control software you can get it to read out the setpoint and what it’s measuring the temperature to be, continuously as it runs, and that makes diagnosis a lot easier.
@John_Bump it seams like the thermister is giving accurate readings, readout, ohms and temp gun all checkout? I think the heater is or something in between is causing This?
Do you have a fan that blow cool air to the heatblock ? I had have this in the past, after the fan starts working i got the tempeture alarm directly, i added some capton tape to the heatblock that solved the Issue.
And may not the thermister is defekt, may the heater is end of life.
And I think I just sucked a micro string of plastic into my mother board fan? Dam I have the best of all luck? Lol
Pids?
@BEN_3D yep, bought extras! I’m learning that with parts from China? Buy extra,
@Jonathon_Thrumble I’m new? Lol and old, when I got my first smart phone, I had to ask wtf a meme was? Elaborate
Intermittent broken cables?
PID settings are possibly out of tune.
if the temperature is getting too hot before settling down, increase Kd and decrease Kp (more creeping up on the temperature and less muscling it around)
if the temperature tapers off just under the target and never quite reaches it, decrease Kd and increase Ki (less creeping up alongside the target, and more correction for cumulative offset) Increasing Ki means that cruising just a hair under the target for a long time will cause Ki to gradually put more power into the heater until it reaches the target. A higher Kd would fight this process by decreasing power to get the measured temperature curve parallel to the target temperature line.
if the temperatures are taking a long time to settle, oscillating or hunting indefinitely, decrease Ki and increase Kd (less agitation from cumulative error, and more gliding into alignment with the target); alternatively try decreasing all three terms… the PID equivalent of taking some deep breaths and relaxing the amount of control you’re exerting.
This last one sounds like what you are experiencing.
Worn thermistor, temp can’t jump that fast
Bad thermistor, or, like happened to me, it was loose.
I’m thinking bad thermal connection with thermistor, or bad wires for the actual heater core itself. PID being off will look more like a flat offset in temperature. You’ll set it to 230, and it’ll reach 200 and stay there, or worse, oscillate like mad.
I replaced the thermister and heater with a set that I know works, seems to be running fine.
@DayRider76 Honestly, just toss the old ones. Not worth the safety risk in keeping them around.
@ThantiK I hear ya, one of my other printers is still down from a fire almost two months ago. I have it back together but this printer has been eating my time?