MaxTemp Triggered error

Hello,

Recently my stepper drivers failed, and after hours of searching for the failure, I've finally started putting back the printer together, (note that i Own two Ramps1.4 boards) And with either one of my Ramps board i get an MAXTEMP triggered, called kill() error.

Now I know exactly what this means, it means that the thermo resistor's resistance has dropped to a zero ( a short). I know hat because I've dealt with this problem for a very long time, and overcame it. Therefor I know exactly what to check: I checked is there a resistance between the thermistors pins (all good), the wires themselves (all good) and I know to check the T0 pins on that board itself. (I used to own a Ramps that had a short there which is why I had to deal with this problem in the first place). And strangely enough, there's no short in between the T0 pins.

and it the same with both Ramps. Has this ever happened to someone? Maybe there's an issue with the Arduino?

cvheck also for shorts between the thermistor and the heater cartridge and also to the heatblock itself.

See I cheched the thermistors leads while it was in the heat block and the ressistance was fine. the weird thing is that even when the thermistor is not plugged to the T0 pins on the Ramps I get "Max temp triggered", even though I should get the "Min Temp triggered". And im positive that there's no short in the ramps board itself, because i've checked like 5 times for that

Then there are only two possibilities

Your firmware is looking at the wrong pin (ie you have changed pins.h or set motherboard incorrectly)

Or the analog pin t0 is attached to is dead. New mega board required... (or you could try using t2, by editing the pin definitions and moving the cable)

Heey, How would i go about changing the pins? i've scroled through so many .h files and i've never seen Pin assignments

in Marlin...

file: pins_RAMPS.h

section:

Quote
from pins_RAMPS.h
#define TEMP_0_PIN 13 // Analog Input
#define TEMP_1_PIN 15 // Analog Input
#define TEMP_BED_PIN 14 // Analog Input

so:
t0 is pin 13
t1 is pin 14
t2 is pin 15

change pins_RAMPS.h to

#define TEMP_0_PIN 15 // Analog Input
#define TEMP_1_PIN 13 // Analog Input

and move your hot end thirmistor from t0 to t2

Edited 1 time(s). Last edit at 09/12/2017 06:35AM by Dust.

Thank You so much. I'll try it

So I've tried it. and it worked. so Thanks a lot for that. However another problem emerged;

none of the heaters are heating up. I turn on the printer, connect to PC and as I watch the temp on both heaters, It just stays the same. now Im used to the heatbed having a hard time warming ups and it takes a few times to do it, but the hot end usually heats up in 3 min., so I've checked the temperature curve, and I see the lines that represents the signal for heating elements, those look fine, but the temperature still does not work.

So Far I've checked:
- the PSU's both work ( i use a separate PSU for heatbed)
-there's no wire that's cut (includng, from PSu to Ramps, Ramps-relay, Ramps - hot end and PSU - heatbed)

Any Idea what could be wrong? Maybe I've missed sth?

Do the X,Y,Z steppers move?

If so we can eliminate the 5amp fuse.
This leaves dead IO pins or dead MOSFETs

You cant easily remap these as the MOSFETs are wired directly to the IO pin, you would have to start modifying the board... cutting tracks and wiring to new IO pins. Do able but is it worth it?

You can check if the IO pins are changing. I would remove the ramps, upload the blink sketch but set the LED pin to D8
Then with a multimeter, or a scope, or a led and resistor (but you have to get polarity correct with a LED) check that it is switching D8 from 5v to 0 and back again... Repeat with D9 and D10

Since you already know the mega is damaged, I would replace it. I suspect the other IO pins have died. including D8 and D10