What is this error?

Hello, I have try my first 3D print yesterday for cheking if it could be done, I have stopped it because the x-end motor support was broken. So I have repaired it and now, I have a communication problem, I can connect but can not do anything, there is the print screen in the jpeg.



Edited 1 time(s). Last edit at 11/01/2013 06:11AM by emmett_Brown.

Tried different baud rates? Probably it has to be 250000. (the COM has to be right too)

Your hot end is trying to set it's self on fire. It's trucking along at ~ 350C. The firmware has detected that (maxtemp) and shut it's self down.

Either:

1) Your hot end is mighty warm
2) Your hot end thermistor is wired wrong / shorted
3) Your hot end thermistor is broke

Of the three, a shorted thermistor is by far the most likely case.

Yes, effecctively, there is a short circuit at the heater; what does it mean?
Is the heater dead? How to repair it, I have to dissassemble the extruder?

Two possibilities:

1) The temperature sensor (the thermistor) is shorted and the hot end is not hot at all.
2) The heater is shorted and the hot end really is that hot.

If it's the thermistor, it's either in the wires up to the hot end, or the wires are touching the body of the hot end. If it's a touch then yes you need to tear things down. The wires out of the glass bead often get pretty close to the metal in some of these designs.

If it's really that hot, the issue is more likely at the Ramps (or what ever) control end of things. Either the heater is always on, or its mis-wired, or your driver MOSFET is shorted / blown. Best guess would be the hot end wired across the power supply terminals.

I have dissassembled the extruder and I can see the ceramic covering the heater, wich one with the greens wires which is short-circuited again. The thermistance is about 100 kohms, ok.
What does it mean?

I would insulate the thermistor wires with kapton tape and make sure they are isolated as well.

I have tried to repair as I can, I have got no more ceramic, can I just monted it as shown below?



Is it good?

Edited 1 time(s). Last edit at 11/03/2013 06:39AM by emmett_Brown.

Wrap each of the thermistor leads in kapton tape. Then tape the pair of them to the body of the hot end. I believe that's where the issue is. In your picture they are the two bare wires that lead into the black shrink tube. It's amazingly easy for them to shift around as your carriage moves back and forth. When they touch you get a maxtemp error right away and the printer completely locks up. Making sure they don't short out can eliminate a lot of "died 15 hours into a 15 1/2 hour print" sort of issues.

I have isolated the thermistance wires with Klapton and hot head too, as on the picture:





Can I reassembled all the extruder now? How many is the hot thermistance, I have about 5 ohms, is it normal?
Thanks for help.

The resistor that heats the hot end typically has a resistance of 5 ohms. That's what you should measure on the heater leads. There should be an open circuit between the heater leads and the metal tip of the hot end.

The thermistor that senses the temperature should read 100K for a normal thermistor. It also should read open circuit to the metal tip of the hot end.

If all that checks out, put it back together and mount in on the printer. Once it's mounted, re-check the resistance readings.

Extruder stwiched off due to MINTEMP trigerred now!
Once all mounted, ~100k on thermistance and ~2 ohms on the hotend. Open circuit between thermistace wires and the metal hotend but I've got a short circuit between the metal hotend and the heater because there is no more white isolant material on it, is the reason why?

The only file it has been changed by a man last week in a FabLab and the print ran after is the "configuration.h".

If you unplug the thermistor from the Ramps, do you still get a maxtemp error? If you do, there is a problem with your ramps board. Possible issues to trigger maxtemp:

1) 4.7K pull up missing or cracked
2) capacitor missing or shorted
3) Short between the pins on the bottom of the board
4) Blown Mega board
5) No +5 on the mega board (should create *lots* of issues*)

That all is assuming that the maxtemp tirggers quickly and without any heat turned on. There are a couple of other things that could be happening if it only triggers after heat has been on.

The short between the heater and the hot end is not a good thing. It's probably not your issue right now. It means the resistor insulation is gone. Once the hot end starts shorting out windings on the resistor you could get a melt down of your wiring / power supply / Ramps board. If it was my hot end, I'd replace at least the resistor if not the whole hot end.

Effectively again; I have a well 4.7 kohms pull-up for the thermistance when I plug off the RAMPS V1.4 from the Arduino board and when I plug in back the two boards, I have 90 ohms pull-up (from Vcc (5V) to THERM0 pins).
Does my Atmega Arduino crashed (Mega 2560)?

p.s: I have noticed too that my THERM1 pull-up for the heating Bed is ok and the THERM2 pull-up is ok too wherease it is not used:
How can change the "configuration.h" file in order to put the 100 kohms thermistance on THERM2 instead of THERM0 with the lines #define TEMP_SENSOR_X ==> but if done, will it really solve the true problem?

Edited 3 time(s). Last edit at 11/04/2013 12:18PM by emmett_Brown.

With a 90 ohm pull up on thermistor input zero, you will never ever trigger a maxtemp condition. You probably would trigger a mintemp error if that's enabled in your .h file.

If your input reads 90 ohms only with the Mega plugged in, then either your Mega is blown or your firmware is configured to use the thermistor zero input as a digital output. If it reads 90 ohms to ground (= it is a pull down), then it will always trigger a maxtemp condition. If it reads 90 ohms to +5V (= it is a pull up) then you will never trigger a maxtemp. If your board is blown, it should be replaced. They are cheap enough on eBay that it's not a costly decision to make.

Made it, hope it will solve my problems...

the new Arduino: [cgi.ebay.fr]

and the new hot end, 0.5 mm nozzle instead of 0.35 mm: [cgi.ebay.fr]

Fortunately EURO is higher than US Dollar...

To be continued... (once delivering)

All this and I get to practice reading French -- seems like I still can, imagine that....(yes part of the pages are in English so it's not *that* good a test).

The Arduino should be fine. They are a pretty generic device. No idea about the J-Head, there is a lot of variation between vendors. I have not bought hot ends from the one you shopped with.

I'll be back!

I have received my new (Arduino) wich calls "Funduino" and which is not Italian but Chinese, that's why it was cheaper.
But, it even runs good and I can now move the printer in any directions but my hotend is really dead because it does not want to warm (~1 Mohms), I have not received yet my new hotend because it comes too from China.
Will give news later when all will be right, and thanks having focalised me on the 4.7 kohms pull-up error I had for the thermistance.
See you later.

Edited 1 time(s). Last edit at 11/12/2013 01:29PM by emmett_Brown.

I have used a number of the clone versions of the Arduino. So far they have all worked as well as the original. They seem to re-name them to get around any legal issues with the name "Arduino".

Great, my new hotend runs good even if it is a 0.5 mm nozzle instead of 0.35 mm previous...
Another and last question to close this topic because it is not really the same "problem": which file in Marlin contains the value of the beta of the thermistance, mine has changed, where can I change it?

The thermistor beta goes into a Python program that may or may not be part of your download. It generates a text file that you can cut and paste into thermistortables.h. You can also do the same thing in a spread sheet program. I've attached a (possibly incorrect) version of the Python program.

Ok, thank you very much, I will try tomorrow, topic solved.