Hi all,

I just got my printer flashed to Repetier Host as of yesterday! I got of a couple prints, but have run into some problems. At some point towards the beginning of every print I attempt, Repetier Host and the LCD screen on the printer show that the temp of the extruder is jumping around. It jumps from 210 to 345, to 119 to 197, etc., etc. Then the extruder will just cool off and stop extruding. Repetier says that the “…extruder temperature sensor failed.”. Is there any way I can fix this? I have absolutely no idea why the hotend just stopped keeping a consistent temperature, or why, if it is just a sensor, the hotend stopped extruding. I did notice that on Repetier it said that the printer had gone into dry mode or something like that, and also that it shut of the extruder once. Any help is appreciated.

-Noah

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Did you use the stock repetier firmware for davinci? If you pick the wrong thermistor it could definitely be off. Otherwise replacement is easy. I’d recommend buying a replacement now and swap it in (just unplug on the extruder and plug it in, no disassembly) because jumping around is usually a thermistor failure. Does it change when you move the wire?

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Hey Nicksears,

As far as I’m concerned, I used the right firmware. When I turn the printer on it says “DaVinci 1.0 Repetier Host XYZ Printing”. I made sure it was set up for my printer (with the arduino software), but flashed it in a bit of a different way than anything else i’d seen. I used CMD and used the “bossac” command to flash the firmware. It seemed to work. I did read about the temp jumping around being the thermistor. It does not change when I move the wires, although when the hotend isn’t heating, if I mess with the wires it will usually heat (this is something I’ve been doing for a while now, even before flashing. Could you give me a link to a good source for the thermistor? Thanks!

-Noah

https://www.amazon.com/gp/aw/d/B010MZ8TCS

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Thanks, will check into it.

The thermistor just came in the mail today. Could you give me a link to a good tutorial on how to go about replacing it? Are any other things needed to replace it, such as glue or solder? Thanks.

Its already mostly assembled if you got the one in the link. All you need to do now is add the connector (sorry i thought the link I sent already had that). I have a tool for this, but you will probably want to just salvage one from something else like this (http://image.dhgate.com/albu\_379583508\_00/1.0x0.jpg) You just want to unplug the old one, plug this in, and see if the temp is still going crazy. Either way pid timing won’t help unless you’ve already done it and messed up the stock constants (or if you’ve changed some other hardware).

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