1 PID Tune
Changing the thermosensor or the heater cartridge is a big change in the system: each of these items has internal errors differing them from each other item. If your thermosensor has a different standard resistance by a small way than the one before, if the resistance of the cartridge is different, then the chip gets readings it does not expect. This is why a change of either of these components (or to a different heater block size/material for the matter) one should run a PID tune, teaching the chip how the new sensor/cartridge behave.
To do this, connect to your Printer via an USB Cable and run a software that can send raw gcode. I prefer Repetier Host, but other software also works. I like to follow the instructions of the e3D v6 assembly manual, but the video by Tom (Thomas Sanladererer) and the RepRap Wiki have excellent explanations too.
- Send
M303 E0 S200 C8
- wait for finishing
- send
M301 with the values you just got returned. One example might read M301 P17.28 I0.63 D118.87
- sent
M500 to update your EEPROM
If this doesn't help, we might have a bigger problem, so let's go troubleshooting! Hardware first, then Firmware.
A few useful hints that Thomas Sanladerer found when he was checking his printers for fire hazards:
- A shorted out thermosensor (closed loop, 0-Resistance) triggers Maxtemp
- A burnt out thermosensor (open loop) triggers Mintemp
- A non-connected or burnt out (open loop) Cartridge triggers thermal runaway, as does any other error with the cartridge that leads to abnormal heating.
2 Check the Hardware
Hardware can fail, we all know that. But luckily there are only 5 items involved that could fail:
2.1 Check all connections
If the heater cartridge is not connected properly, that will result in a Thermal Runaway Error, as the thermosensor does not detect any change.
A non connected thermosensor will trigger a mintemp error, a shorted thermosensor will trigger maxtemp error.
2.2 Check the resistance of the heater cartridge
A broken heater cartridge can have two results: either it conducts no electricity at all (for example if a lead is broken), or it acts as a jumper and has no resistance at all. To check this, use a multimeter and measure the resistance in Ohm by connecting it to the leads of the cartridge while it is dismounted. A broken circuit in the cartridge triggers Thermal Runaway, a shorted out cartridge can break the board in worst case. A pictoral guide for analogue Multimeters.
My e3D light6 in my 12 V TronXY has a resistance of about 5.2 Ω. The Value you will get depends on what kind of heater cartridge you use. For reference: e3D Heater Cartridges are documented to be around 4.8 Ω for 12 V & 30 W, 3.6 Ω for 12 V & 40 W, 19.2 Ω for 24 V 30 W and 14.4 Ω for 24 V 40 W.
If your Value is given as infinite or near 0 Ω, your heater cartridge is broken - Though having 3 defect heater cartridges seems unlikely on first glance, unless something shortens their lifespan considerably.
2.3 Check your supply voltage
Now comes a thing that can be dangerous for you will measure a live circuit. Be aware that you are working with live current when you do this. Do NOT bring your fingers into contact with unshielded wires!
Set your Multimeter to check the Voltage. Connect the test probes to the output of the power supply that runs into the board. Power up the voltage supply. It should read close to 12 or 24V, depending on your machine.
2.4 Check the voltage given by the board
Again, this is measuring live current and can be dangerous. Use maximum care not to fry yourself!
If your Power supply is working, then it might be the board that is not allowing the current to get the heater cartridge. So we need to measure if it gets power. Since I=U/R, and we have established that R is not 0 or infinity (see above), we can establish if there is I by simply measuring U, which is the voltage.
Mount the tips of your multimeter into the clamps that should take the leads for the heater cartridge and set it to measure the Voltage. Make sure they have contact. Connect the machine to power and start it up. Order it to heat up the cartridge. It should show a voltage that is similar to your supply voltage (12/24V).
2.5 Thermosensor
The Thermosensor might trigger an error if it is faulty but not entirely broken. A broken thermosensor should trigger MINTEMP for a broken open and MAXTEMP for a shorted out sensor. The only way to test this would be to measure it against items of known temperature, for example using the bed sensor as Benchmark.
3 Check the Firmware
3.1 Thermosensor settings
In some cases, the temperature tables of the thermosensors are not compatible and one has to change the settings for that in the firmware. One of the best rundowns I know is in the e3D light6/v6 firmware manual, if you need more help than this.
In the Marlin 1.9 you do this in Configuation.h, under the header Thermal Settings. In my Ender 3 this is done in line 289:
#define TEMP_SENSOR_0 5
That means, that my temperature sensor 0 (the one in the hotend) is of type 5, where type 5 is defined in the block above. The relevant line 256 of my file reads:
* 5 : 100K thermistor - ATC Semitec 104GT-2 (Used in ParCan & J-Head) (4.7k pullup)
The most common choice in Chinese hotends to use this very 4.7-kiloohm pullup thermistor table, and the actual specific table for most of these is reasonably close to the 5. Other thermosensors can be reasonably overlapping, but in case you change the style of thermosensor, it is generally advised to change this value accordingly1. Always run a PID tuning after changing the thermosensor table!
3.2 Thermal Runaway Protection
The settings for the Thermal Runaway Protection might be worth a look. Maybe it is a little trigger happy? Configuration_adv.h contains a block titled Thermal Settings, containing when to trigger the emergency shutdown. For my Ender3 it reads like this:
#if ENABLED(THERMAL_PROTECTION_HOTENDS)
#define THERMAL_PROTECTION_PERIOD 40 // Seconds
#define THERMAL_PROTECTION_HYSTERESIS 4 // Degrees Celsius
From your error log, I guess that your printer has the second line as 30 seconds. It would be technically safe to increase this time to up to 120 seconds, but I strongly suggest not to go over 60 seconds.
1 - I had switched the whole hotend on my TronXY X1 for an e3D light6, and it only needed a PID tune, but in theory I should have also swapped the Firmware to reflect that - but, as said, luckily many Chinese printers use the table 5 even if they are not using the sensor. Table 5 was made for the thermosensors used by e3D.
