1 Topic by iacopo

  • iacopo
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Topic: extruder thermocouple reading seems off

First of all I wanna thank you all guys!
I did my first print yesterday and thanks to the manual bed leveling tutorial here I got the print to stick perfectly without using any glue.

When my da vinci starts warming, the temperature readings from the heated bed and extruder thermocouple are totally different.
The heated bad reading is just fine, it says 23° which is my room temperature, while the extruder temp reads 10°, which is way off.

Is this a common issue?

Since I'm using Simplify3D to print, I can manually change the temperatures, so I'm wondering if I should set a temperature knowing the thermocouple reads 13 degrees below the real temperature.

2 Reply by owenransen

  • owenransen
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Re: extruder thermocouple reading seems off

iacopo wrote:

First of all I wanna thank you all guys!
while the extruder temp reads 10°

See my post earlier today about issue 0011  (for the extruder anyway)

Author of  PhotoToMesh, for making bas-reliefs and
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3 Reply by iacopo

  • iacopo
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Re: extruder thermocouple reading seems off

I don't think our issues are related.
My da vinci reads the extruder temperature, I simply suspect it reads a wrong value, which is lower than reality

4 Reply by carl_m1968

  • carl_m1968
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Re: extruder thermocouple reading seems off

You could compensate, but that is just a bandaid and thermistors do not work in a linear fashion. That is why there thermistor tables in the firmware. At certain ranges the difference will change. So the correct fix would be to first get e new thermistor. It is just a common 100K thermistor that you can find all over ebay.

If you have a digital multimeter you can measure the resistance across the thermistor as well. it should be near 100K ohm at room temp. If your are getting 10 degrees at room temp then I would think you will get a much different resistance if the it is the source. Otherwise it could be your main board or the interface board on the head.

Printing since 2009 and still love it!
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5 Reply by iacopo

  • iacopo
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Re: extruder thermocouple reading seems off

carl_m1968 wrote:

You could compensate, but that is just a bandaid and thermistors do not work in a linear fashion. That is why there thermistor tables in the firmware. At certain ranges the difference will change. So the correct fix would be to first get e new thermistor. It is just a common 100K thermistor that you can find all over ebay.

If you have a digital multimeter you can measure the resistance across the thermistor as well. it should be near 100K ohm at room temp. If your are getting 10 degrees at room temp then I would think you will get a much different resistance if the it is the source. Otherwise it could be your main board or the interface board on the head.

Thanks! Will try!

6 Reply by owenransen

  • owenransen
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Re: extruder thermocouple reading seems off

iacopo wrote:

I don't think our issues are related.
My da vinci reads the extruder temperature, I simply suspect it reads a wrong value, which is lower than reality

What made me reply was that my extruder temp was stuck at exactly 10° (like yours) for about 10 minutes then I got the 0011 error. In my case it's probably the rubbish connector as shown (and fixed) here:

http://www.youtube.com/watch?v=xyn6TOsemqI

Author of  PhotoToMesh, for making bas-reliefs and
lithophanes from your photos and images
http://www.ransen.com/PhotoToMesh

owenransen's Website

7 Reply by Jacek (edited by Jacek 2015-02-12 15:23:59)

  • Jacek
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Re: extruder thermocouple reading seems off

Hi, did you solve the problem?
If not I might have suggestion because I'm already solving this problem as well. My printer also claims that temperature of the nozzle is 10C no matter what the real temperature is. The same result is if the termistor is completely plugged off...
It means that it is termistor broken or it is somewhere disconnected. First check plugs in printers head, they are crappy and easily covers with rust and stops to conduct... If plugs are ok, it is probably thermistor...
In my case one of the wires broke just near the thermistor's glass head so it naturally stopped working. Why did it happened?
I guess the reason is fact that it is placed not deep enough inside the nozzle so the bulb and wires sticking out are just at the nozzle's edge.. When the printer was new it was protected with some silicone sealant but after 500h of print and cleaning nozzle with brush the silicone was mostly gone, so every time the nozzle was cleaned the wires were free and bent many times.. finally broke. You might not see this before disassembling the nozzle, because silicon was applied also inside the hole, so the wires are probably still locked in it even if they are broken... Once I removed my termistor I realized that there was no conduction at all...
I've already orderer few of them (they are cheap app. 1-1,5€ on ebay), so now I'm waiting for them to be shipped, so I can hopefully fix my printer...