Extruder 1 Heats Slowly - Dual Extruder


I recently installed a dual extruder onto my Taz 5 and I installed the required firmware as instructed.

Extruder 1 is having a very difficult time heating. In the last 1.5 hours it has heated to only 39 degrees.
Extruder 2 heated to 240 within just a couple minutes.

I confirmed the cables are all plugged in correctly and even attempted to re-flash the dual firmware a couple times, however I’m not having any luck.

I searched the forums but haven’t found anything similar to this issue, so I’m hoping some of you may have some ideas.

That’s only 102f. I’m guessing you have the second thermistor sensor wired correctly but the other hotend heater cartridge is not correct or is not enabled in the firmware. The heat increase your are seeing is probably residual heat from the bed and the other hotend. You will want to check the heater cartridge and make sure it is intact, check the firmware you uploaded is the dual extrude version and check that your heater cartridge is going to the correct board header.

Thanks for the quick reply.

I did some more troubleshooting and I’m a bit concerned one of the extruders may be bad.

First Setup:
Extruder 1: Back (black sleeve connectors)
Extruder 2: Front (blue sleeve connectors)

I powered down the luzbot and switched the connectors around. Upon powering up I found the extruders changed as expected.

Second Setup

Extruder 2: Back (blue sleeve connectors)
Extruder 1: Front (blacks leeve connectors)

The back extruder still would not heat up while the front one did just fine. This leads me to believe it wasn’t really an issue with the connectors on either sleeve without ruling out the possibility the back extruder or its connectors are bad.

I’m currently waiting for it to cool down to I may dismount it and give it a closer inspection.

The firmware I used is titled Marling_dual_extruder_TAZ4 as I could not find any specific to TAZ 5. I downloaded it from the instructions located at https://ohai-kit.alephobjects.com/project/taz4_dual_extruder/

OK, first off, what extruders are you using with this? The Taz5 shipped with the Hexagon hotend. The Taz 4 dual extruder firmware is designed for two Buddaschnozzle hotends, which use a different type of heater core and possibly a different thermistor.

The configuration.h file has several differences between the 4 and the 5 firmware. For example:


#define TEMP_SENSOR_0 7
#define TEMP_SENSOR_1 7
#define TEMP_SENSOR_2 0


#define TEMP_SENSOR_0 5
#define TEMP_SENSOR_1 5
#define TEMP_SENSOR_2 0

// 5 is 100K thermistor - ATC Semitec 104GT-2 (Used in ParCan & J-Head) (4.7k pullup)
// 7 is 100k Honeywell thermistor 135-104LAG-J01 (4.7k pullup)

// If you are using a preconfigured hotend then you can use one of the value sets by uncommenting it
// Buda 2.0 on 24V
#define DEFAULT_Kp 6
#define DEFAULT_Ki .3
#define DEFAULT_Kd 125

// AO-Hexagon (24V)
#define DEFAULT_Kp 28.79
#define DEFAULT_Ki 1.91
#define DEFAULT_Kd 108.51

I haven’t looked at the firmware enough to even tell if you can specify two different types of hotend inside firmware.

Either way, it may quite vary well be in the firmware itself if you are trying to mix hotends, or you may have damaged the heater core itself during installation, which can happen. Or its plugged in wrong.

Thanks again for the reply.

Looking through the parts, I can confirm the dual extruder is using the Buda 2.0 nozzles. They look exactly like the following, significantly different from the single extruder which came with the TAZ 5.


The dual extruder I purchased is for TAZ 4-5 models.


For the sake of it, I tried making the changes to the Configuration.h as you provided. Unsurprisingly, being its the Buda 2.0, the results did not change. The back extruder still would not heat up.

I did examine the dual extruder as best I could with my inexperienced eyes. I saw no apparent physical damage to the unit or wires, and the connectors appear to be in excellent condition as well.

Not sure how I could have damaged it during installation, but I suppose it may be possible. I assume the unit was tested before being shipped as both extruders already had white filament in them.

I went ahead and reinstalled the single extruder and firmware. It’s heating up just fine. The issues is definitely with that back extruder, hardware or firmware I’m uncertain.

Well if you swapped cables between the extruders and it did not change which extruder did not heat up then the back extruder has an issue.