1 Topic by docterhow

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Topic: Strange Temp fluctuations (E3D V6)

I installed my E3D and had a bad thermistor,replaced it and got the thing working, with table 5 in repetier. I got fairly accurate ambient temps of 20° C. I then went on vacation over spring break and now that I am back, the thermistor is reading fluctuates between -3° to -4°, while the bed temp is about 20° C. I verified that the thermistor isn't broken and that nothing has been changed firmware wise or anything. I also flashed repetier .92 again making sure all the settings are right to it and still get the incorrect readings. Any ideas on what to try or do?

2 Reply by qtoppa

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Re: Strange Temp fluctuations (E3D V6)

Check the area that you crimped/soldered it.  Any changes in resistance will make it fluctuate.

3 Reply by docterhow

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Re: Strange Temp fluctuations (E3D V6)

I did have one of the crimps loose, and fixed it. However, had the error still. I then unplugged the thermistor from the break out board and the lcd still read the -3 to -4 temp. I'm surprised it didn't say the "def" error, as nothing was plugged into the thermistor plug. Now I am puzzled, what could it be?

4 Reply by jagowilson

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Re: Strange Temp fluctuations (E3D V6)

Sounds like it's still not making connection at the molex plug. If you have a multimeter see if you can't get your probes into the molex and read resistance. I'm willing to bet it shows an open circuit.

5 Reply by docterhow (edited by docterhow 2015-03-29 17:55:48)

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Re: Strange Temp fluctuations (E3D V6)

What should the molex connector read on the multimeter?

EDIT: From red to black wires it reads 98 Ω. Is that what it should be?

6 Reply by jagowilson (edited by jagowilson 2015-03-29 18:37:39)

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Re: Strange Temp fluctuations (E3D V6)

No that is far too low. It should be reading in the kilaohm range. I think you've got a broken connection somewhere in the chain. Check it at the thermistor's legs, if they are still accessible.

Thermistors are fragile and I've broken some myself so don't feel bad if you broke it somehow. They're cheap and you should definitely pick up some spares.

7 Reply by qtoppa

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Re: Strange Temp fluctuations (E3D V6)

I couldn't get accurate readings with it plugged into the board so I skipped it.  Get much better readings now.

8 Reply by docterhow (edited by docterhow 2015-03-29 19:47:44)

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Re: Strange Temp fluctuations (E3D V6)

Looks like I found the culprit. The white connector of the thermistor to breakout board broke.
http://soliforum.com/i/?9L95bom.jpg
Anyone know where to get some of these connectors? Preferable already assembled.

9 Reply by kev0175

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Re: Strange Temp fluctuations (E3D V6)

It is a JST connector.  You can find them on eBay or Amazon

Da Vinci  AiO with firmware 1.1.1 using xyzscan 1.1.18
E3Dv6 hotend with custom carriage with Borosilicate glass bed
123D Design and Simplify3D, Replaced PS with a Solidgear Flex320
Zerokart resetter,  Installed a Extruder Controller for higher temps