temperature don't rise to degrees set and drop to 0°

Hello, I'm from Argentina.
We are having some issues with our 3d printer prusa explorer.
When I start the program, after connecting the printer y set the temperature to 185° (Pla) to start making test of extrusion. The problem is, it never gets to 185°, at least reachs 160° but after that, the temperature drops to 0°, and then perhaps oscilates between 0° and 60°.
I try for hours checking if the temperature rise and let me extrude...but no..
I verify that the noozler is hot..and I can extrude by hand the pla..
I verify and it seems the wiring is ok.

If someone can help me I will appreciate.

Gastón

Maybe the connection of the thermistor become intermittend at 160°C. ( solder get´s soft ).
You should check the thermistor wires, if they are crimped to the sensor legs or just soldered...
-Olaf

How did you place the thermistor in your hotend? They have little naked pins, and if they are not properly insulated (with kapton, often), you can have a short circuit.

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Prusa i3 - e3d v5 - Gnu/Linux - Pronterface - Slic3r - Octoprint - Rpi - French

Someone have a picture or something where I can see where the thermistor is??
I have been testing printing before this error happens...
In one test when I put the extruder in the zero axis.. the z axis missed the sensor and keep going down and push the table...maybe there the thermistor went soft.. I don't remember after calibrate everithing I achieve print something or started this problem

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Prusa i3 - e3d v5 - Gnu/Linux - Pronterface - Slic3r - Octoprint - Rpi - French

I disarmed the hot end, and I found after taking off the tape, the wires absolutly burned,
I attach photos of what I found, the wires crack when i finish taking the tape off.

Someone have some advice and how I can fixed the thermistor?
I supposed that the wires broken were from the thermistor.

can I find the replacements in a electronic store?

Thank you

WOW, this hotend has seen some serious overtemperature!

You better look for a complete new heaterblock.
-Olaf

F****!!...
But can it be fixed?? just to make some test and print small stuff..

The thermistor is dead and the heater element is probably damaged, too. Maybe the heater is still working, but the glassfibre insulation is mostly burnt. Try to cut off the useless part and see if the rest is still usable.
Then disassemble the nozzle and the heater block from the PEEK part. See how it looks from inside, if it´s still useable.
-Olaf

the heater is still working becaus when I tested it was still hot.. the thermistor is a cheap part, but all the heather block is a little expensive..

Ok, to start with the thermistats are cheap, but the wires from the thermistat must slide through a very thin telfon tube (About an inch or so) and then connected to the wiring to the board. The teflon tube protects the wires from the heat. Aluminum block, therimistat and teflon tube will not be expensive at all.
[www.ebay.com.au]
[www.banggood.com]

And I bought 1M of .1mm diameter teflon tube from a local supplier for $1.30.

Heater Cartridge [www.banggood.com]

It wont cost a lot if thats what you have to replace, then just wrap it back up with teflon tape (again fairly cheap on Ebay.)

Or maybe you are just better of getting a complete head and wiring [www.banggood.com].

Generally dont be pressing the heater cartridge wires hard up against the heater block, unless you are going to wrap the cables in telfon tape for protection, and the teflon tube for the the thermostat wiring basically provide the same protection

Edited 2 time(s). Last edit at 07/08/2015 06:07AM by Chaser30.

thank you!
I 've been looking here in Argentina... I see the components are not expensive.
Now I have to make the list...and wait that the company buy it