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Need help troubleshooting your BoXZY 3D Print Head? You're in the right place!

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3D print head undetected on print initialization

Weird issue: 3D print head installed, and been working all morning. Now every time I start to print the "CNC Head Detected" message appears...

Sometimes it seems to coincide with the z-axis limit switch - when it does it's home manoeuvre prior to heating the extruder. And sometimes it coincides with the extuder heating up (maybe around the 160 degree mark).

Tested the quick change head cable with a multimeter and it checks out OK. I even swapped it for the limit switch cable and still didn't solve it.

Plugging in the Laser makes no difference, still says "CNC Head Detected". Laser was used yesterday without any issues.

I've left it a while and the 3D print head gets detected again, but not the laser... And no sooner as I try 3D printing again I'm back to the CNC head detected!?!?...

What is happening? Any troubleshooting tips?

Update (02/21/2017)

OK, so the quick-change heads need to be in the holder to be detected correctly. They are grounded to the gantry, which explains why I wasn't seeing the laser detected (I was holding it).


It does seem to be a temperature related issue... The extruder hits 155 degrees, then "CNC Head detected" appears.

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Update (02/21/2017)

Looks like the thermistor is foobared. Replacement reads around 117 kilohms. Going to swap the units over...

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Yep, dodgy thermistor. Problem solved by replacing it...

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Nearly 2 years later, the same thing happened today.

Replaced, and now back up and running again :)

Not sure what the lifespan of a thermistor should be, but it's printed A LOT of 3d parts in the time since that last failure!


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Matt will be eternally grateful.
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