<p>I am not sure what the hardware config is for the <strong>Tevo Tarantula</strong></p>

<p>Make sure your <code>configuration.h</code> file is setup for your hardware.
The extruder defines are describe in <a href="https://github.com/JimBrown/MarlinTarantula/blob/bugfix-1.1.x/Marlin/Conditionals_LCD.h" rel="nofollow noreferrer">Conditional_LCD.h</a></p>

<p>It looks like the <a href="https://github.com/JimBrown/MarlinTarantula/blob/bugfix-1.1.x/Marlin/Configuration.h" rel="nofollow noreferrer">configuration.h file</a> on GitHub is configured for a single extruder.</p>

<p>For example, if you have 2 hotends; but, "HOTENDS=2" is not set then the I/O will not be configured for the 2nd hotend.  I just looked at the code and if <code>HOTENDS == 1</code> then the <code>MOSFET_D_PIN</code> will be used to control FAN1 (which sounds very similar to what you are describing that you are seeing).</p>

<pre><code>  #if HOTENDS == 1
    #define FAN1_PIN     MOSFET_D_PIN
  #else
    #define HEATER_1_PIN MOSFET_D_PIN
  #endif
</code></pre>

CC BY-SA 3.0
2017-06-03T02:48:05.310Z
If the tarantula uses a single hotend, don't define SINGLENOZZLE but define SWITCHING_EXTRUDER and (i think) EXTRUDERS=2.  Then the code will expect the single hotend to be connected to D10.
markshancock
CC BY-SA 3.0
2017-06-03T13:21:47.277Z
Thank you for the direction to go. The setup is dual and I "thought" I had checked that.
Evan Weber
CC BY-SA 3.0
2017-06-03T22:14:58.770Z
"Dual" can mean several things.  Do you have two separate extruders (hotends), a (single) mixing extruder, or a (single) standard extruder with a dual filament feeder?  Marlin has to be configured for the specific type.
markshancock
CC BY-SA 3.0
2017-06-02T20:01:55.997Z
2017-06-06T03:12:49.277Z
2017-06-06T03:12:49.277Z
markshancock
<p>So, following on from <a href="https://3dprinting.stackexchange.com/questions/4177/dual-extruder-setup-in-marlin/4179#4179">Mark's answer</a>, in <a href="https://github.com/JimBrown/MarlinTarantula/blob/bugfix-1.1.x/Marlin/Conditionals_LCD.h#L298" rel="nofollow noreferrer">line 298</a> of <a href="https://github.com/JimBrown/MarlinTarantula/blob/bugfix-1.1.x/Marlin/Conditionals_LCD.h" rel="nofollow noreferrer">Conditional_LCD.h</a>, you would need to change:</p>

<pre><code>#define HOTENDS       1
</code></pre>

<p>to</p>

<pre><code>#define HOTENDS       2
</code></pre>

CC BY-SA 3.0
2017-06-06T03:09:09.517Z
2017-06-06T03:09:09.517Z
Greenonline
<p>I had a similar problem, my documentation was wrong and the heater &amp; thermistor were wired in backwards. Maybe recheck your wiring and even try reversing the temp sensor on your board.</p>

CC BY-SA 3.0
2017-07-21T03:36:44.007Z
Do you mean that you swapped the heater and thermistor connections, or do you mean that the thermistor was connected to the right therminals - but backwards? Thermistors and heaters are generally not polarized, and can be connected either way around. They're just simple resistors.
Tom van der Zanden
CC BY-SA 3.0
2017-07-20T16:51:34.363Z
2017-07-20T16:51:34.363Z
Jason
<p>I have a Tevo Tarantula with a MKS Base 1.5 board and dual extruders.  I am running Marlin RC8 Tevo Community build for the dual extruder, large bed and SN04 sensor.  </p>

<p>All temperature sensors work and give accurate reading but <code>E1</code> when activated runs at 100% until the overtemps kicks in and shuts down the system.  Like I said, it reads proper temperatures through the thermistor it just won’t stop at the set temperature.  I checked the MOSFET and there is no obvious scorching or bad solder joints on the MKS board.  This leads me to believe it is a mix-up in firmware but, being a bit of a newbie on this, I am still getting familiar with G-code and Marlin.</p>

<p>I have confirmed the correct board is being referenced in firmware from <code>boards.h</code> but looking at <code>configuration.h</code> I just get confused.  What I am thinking is somehow/somewhere <code>E1</code> might be referenced as a fan that is just off or on.  Anybody have ideas?</p>

CC BY-SA 3.0
2017-06-02T19:38:59.930Z
Is [this build](https://github.com/JimBrown/MarlinTarantula) what you are using?
markshancock
<dual-nozzle>
Dual extruder setup in Marlin
Evan Weber
# Dual extruder setup in Marlin

(Asked by: username_0 on 2017-06-01)

I have a Tevo Tarantula with a MKS Base 1.5 board and dual extruders. I am running Marlin RC8 Tevo Community build for the dual extruder, large bed and SN04 sensor.

All temperature sensors work and give accurate reading but `E1` when activated runs at 100% until the overtemps kicks in and shuts down the system. Like I said, it reads proper temperatures through the thermistor it just won’t stop at the set temperature. I checked the MOSFET and there is no obvious scorching or bad solder joints on the MKS board. This leads me to believe it is a mix-up in firmware but, being a bit of a newbie on this, I am still getting familiar with G-code and Marlin.

I have confirmed the correct board is being referenced in firmware from `boards.h` but looking at `configuration.h` I just get confused. What I am thinking is somehow/somewhere `E1` might be referenced as a fan that is just off or on. Anybody have ideas?

**Tags:** dual-nozzle
> **Comments:**
> **username_1**: Is [this build](https://github.com/JimBrown/MarlinTarantula) what you are using?  

---

## 3 answers

### Answer by username_1 on 2017-06-02. Score: 1

I am not sure what the hardware config is for the Tevo Tarantula
Make sure your configuration.h file is setup for your hardware.
The extruder defines are describe in Conditional_LCD.h
It looks like the configuration.h file on GitHub is configured for a single extruder.
For example, if you have 2 hotends; but, "HOTENDS=2" is not set then the I/O will not be configured for the 2nd hotend.  I just looked at the code and if HOTENDS == 1 then the MOSFET_D_PIN will be used to control FAN1 (which sounds very similar to what you are describing that you are seeing).
  #if HOTENDS == 1
    #define FAN1_PIN     MOSFET_D_PIN
  #else
    #define HEATER_1_PIN MOSFET_D_PIN
  #endif

> **Comments:**
> **username_1**: If the tarantula uses a single hotend, don't define SINGLENOZZLE but define SWITCHING_EXTRUDER and (i think) EXTRUDERS=2.  Then the code will expect the single hotend to be connected to D10.  
> **username_0**: Thank you for the direction to go. The setup is dual and I "thought" I had checked that.  
> **username_1**: "Dual" can mean several things.  Do you have two separate extruders (hotends), a (single) mixing extruder, or a (single) standard extruder with a dual filament feeder?  Marlin has to be configured for the specific type.  

---

### Answer by username_2 on 2017-06-06. Score: 0

So, following on from Mark's answer, in line 298 of Conditional_LCD.h, you would need to change:
#define HOTENDS       1

to
#define HOTENDS       2


---

### Answer by username_3 on 2017-07-20. Score: 0

I had a similar problem, my documentation was wrong and the heater & thermistor were wired in backwards. Maybe recheck your wiring and even try reversing the temp sensor on your board.

> **Comments:**
> **username_4**: Do you mean that you swapped the heater and thermistor connections, or do you mean that the thermistor was connected to the right therminals - but backwards? Thermistors and heaters are generally not polarized, and can be connected either way around. They're just simple resistors.  

---

