1 Topic by devernham

  • devernham
  • Newbie
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  • From: Lompoc, Ca.
  • Registered: 2014-05-06
  • Posts: 5

Topic: Hot End testing.

I checked the resistance on the to plugs. The one with the green wires, is 7.1Ohms, There is nothing on the clear wires. The heat has been coming up to temp then dropping. Thinking of buying the whole front of the extruder, since I bought my machine used and the acrylic part is broken to. The tutorial says the green wires are supposed to be 5.4. is 7 bad? Why would the other wires return nothing?

2 Reply by grob

  • grob
  • grob
  • Member
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  • From: Sydney, Australia
  • Registered: 2014-01-02
  • Posts: 900

Re: Hot End testing.

Green (heater) being a bit high is ok, it will still heat, just slower! The heater resistors can drift like this with age/use.
I'm not sure what you mean by 'nothing' on the transparent (thermistor) wires. 0 ohm (short circuit) or open circuit?

Heat rising then dropping is usually an intermittent thermistor problem, if it's properly broken it usually doesn't heat at all. I think you may be lucky and can fix the thermistor just by recrimping the connections. Look this up on the forums, it's a common problem and covered pretty well.

Is the acrylic properly broken, or just cracked (and still functional)? This is also pretty normal either way. Consider replacing the acrylic part with the printed "lawsy mk5" extruder, this is easier to use and not susceptible to cracking in the same way. Again, a common modification, plenty of help here on the forums.

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi