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I am looking for troubleshooting help on my printer. Recently the hot end just can muster the courage to go past about 70 °C.

The hardware - Ender 3V2 with a E3D V6 hot end. 24 volts

I changed the thermistor to a new one. Before heating, it registers an appropriate 10 °C in line with the bed temp sensor.

With the thermistor checked good, I looked at the heater element. It is reading 22 Ω. The documentation from E3D is not clear in what wattage heater I bought, but if it is a 30 W 24 V heater, it's on the high end of acceptable.

  • A 24 V 30 W heater cartridge will read between 16.7 - 22.6 Ω.
  • A 24 V 40 W heater cartridge will read between 12.3 - 15.1 Ω.

If anyone is able to confirm how to know what my heater wattage is supposed to be, LMK. Options are shown for blue wires, red wires, and yellow. I have yellow.

If the resistance is in spec, I checked if the voltage being supplied to the heater is correct. It is reading 23.6 V which seems good.

I have attempted to PID autotune in Pronterface which I had also done several times previously before the issue. If I try to target anything over 70 °C, the attempt to tune fails because it can't get hot enough. I can tune if I set the temp to 65 °C by comparison.

The temperature trace in Pronterface shows the temp rising quickly through the 30s, 40s, then plateauing and maxing out in the high 60s.

I am looking for advice on where to look next for trouble shooting. Seems odd to suddenly have such a low temperature limit capability that I can't root cause.

Greenonline
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Will Wilson
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2 Answers2

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There are several points to check to trouble shooting this issue but commonly there are a loose part.

  1. The heating elements is loose, try to tight the cartridge to the aluminum block.
  2. The Sensor temperature is not touching the aluminum block or is outside of its position. Maybe the heating element is correct but the sensor is not taking the right value.

If the temperature rises too slow and downs more quickly than normal is due the temperature sensor is out of it position.

Other issues: The PWM control is over heated, so this will need to replace it or change the transistor (FET), however this is not a common problem.

The other one and more common that PWM over heated is the Power Source, as well like the PWM control the power source decreases his potencial on current supply. For me is easier replace the power source instead verify the PWM control.

Now I´ve done that for second time in 6 years of printing. How Can I deduce that the PWM is not overheated?, I have a cooling fan for all PWM controls on the RAMPS 1.4 Module.

Fernando Baltazar
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If you're using the same RTD for both tests you can rule that out as a source of the problem. At this point I'd suggest, A) thoroughly scrubbing all the machine parameters and software settings for something that's limiting temperature or duty cycle, and, B) buying or borrowing an O'scope to see what the board is really putting out. Connecting the heater to the bed heat pins will be limited to however high the bed heat can be set so may not tell you much. I don't know if it's possible to swap hot end and bed outputs in software. If so, I don't know how.

allardjd
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