Hot end wont heat up. Please help!

My friend gave me his Pusa Mendel Iteration 2, I'm running sprinter.
My electronics are RAMPS 1.4 with Arduino Mega 2560.
I have connected the printer to pronterface, (btw Im using a Mac Mini) I am calibrating everything to begin printing, everything moves and stops where it is supposed to but only the heat bed is heating up. I checked the 100K thermistor on the hot end and it works.
Funny thing, the temp reading for the hot end always reads 0, so I thoght the thermistor was shot, well to test it I plugged the hot end and thermistor into the heatbed ports and the hot end worked fine as well as the thermistor. The power does not come out of D10 to the hot end and the thermisor is not reading the current temp as 33 degrees. I just replaced the RAMPS and there is no change. Do you guys think it is the Arduino?
What should I do?
Thank you for your time I would really like to print something.

Best,
Lance-

Most likely that the arduino has a blown input, if you are getting 0 on the read. There was probably a short at some point during the initial build. Most firmware won't even let you turn on D10 without a valid temperature reading. 0 is not valid.

jcabrer Wrote:
-------------------------------------------------------
> Most likely that the arduino has a blown input, if
> you are getting 0 on the read. There was probably
> a short at some point during the initial build.
> Most firmware won't even let you turn on D10
> without a valid temperature reading. 0 is not
> valid.

Thanks for the response Jcabrer
It stopped working when my friend Robert had it, he thought the hot end just got clogged up after he had printed. It fried that input somehow after working fine for months.
I'll get a new Arduino and post back here with the results. At least I have 2X RAMPS now, I'll use it to build another printer
L-

maybe the firmware are you sure in your gonfigs you have enabled both thermistor?

do you have separate power supply setup for d9 / d10?

The bottom pair of connectors marked 5A power the stepper drivers and Extruder heater/fan (D9, D10).


also set board to use ramps version of board. ramps 1.4 exchanges a fan i/o for an extra extruder.

ramps wiki [reprap.org]

Okay, I got the new arduino and that solved the problem, something was fried. It is working great now
Thanks for all the input guys!

i have the same problem i am using sanguinololu 1.3a with ATMEGA 1248p. i am using the ready made Extruder

"http://www.ebay.com/itm/190827330027?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649"

i dont know the thermistor value. but when i connect the thermistor and check the temperature it gives 375*c. also i am not getting the hot end out put from the board please help.....

Sounds like your thermistor or the wiring to it is short circuiting

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Waitaki 3D Printer

Yeah the thermistor needs to be the correct value, as in the same value that is written in the firmware, in my case 100k thermistor which is defaul in the Sprinter firmware for the RAMPS 1.4