Hot end and heat bed won't heat to full temperature on Rework I3

So close to getting my first printer going. I have a Rework I3 with Ramps 1.4, E3Dv6 hotend, and MK2B heatbed. In Pronterface I try to heat the hot end up and it won't go above 140C but when I check the hot end with an infrared thermometer it is only around 30C. The light on the Ramps stays on and solid red while heating. When I heat the bed I have similar issues, it won't get very hot and reports quite a bit different than when i take surface temp. The red LED on ramps and blue led on MK2B turn on and as it heats higher they both flicker. I checked the voltage on the bed when they are flickering and it is very sporadic between 8 and 12 volts. Any suggestions for my Marlin or other settings? I assume the pronterface is just reading what I uploaded from Marlin and is not changing settings on top of Marlin?

I have Marlin set for the following:

#define TEMP_SENSOR_0 5
#define TEMP_SENSOR_1 0
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 1

I think they are right. I tried the PID tuning and get a failure timeout error. Is there a way to ohm out the thermistors to determine I have correct wiring and no shorts? Is there any special settings I need to do in Pronterface? Why would the bed voltage fluctuate when heating?

My power supply is 12v 30A [www.amazon.com]
When the hotend is heating I checked the voltage at the blue terminals where the hotend wires go in and its getting 12.8v.

Is there anything that I should be checking in Pronterface or the Repetier that would screw something up?

Any other constant value you havent checked, your thermistor is it a 100k NTC?

I thought bed voltage was always 0 or 12 volts, considering they use PWM, shouldn't it be 0 or 12 output? 8V might due to the appeared voltage that your multimeter see.

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Originally Posted by richardphat

Any other constant value you havent checked, your thermistor is it a 100k NTC?

I thought bed voltage was always 0 or 12 volts, considering they use PWM, shouldn't it be 0 or 12 output? 8V might due to the appeared voltage that your multimeter see.

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I would like to check the thermistors but not sure how, I assume I would check resistance but what is the value I should get to know they are working? The hotend thermistor is the standard one from E3Dv6 and is a Semitec 100k I believe.

Not sure what bed voltage is supposed to be. What is PWM and how can i check it?

Pulse Wave Modulation;PWM, basically it's some sort of switch/relay that is much better at handling higher frequency. This switch close the loop allowing current to pass through your heat bed, if the temperature is reached or above, this switch opens the circuit and the current stop flowing.

If your model use mosfet (basically an electronic switch) instead of a mechanical relay, it would explain why your heat bed flickers with its LED.

By the way did you put that 4.7k ohm on your board? The whole idea of measuring the temperature with a thermistor is basically a voltage divider.

Quote:

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Originally Posted by richardphat

Pulse Wave Modulation;PWM, basically it's some sort of switch/relay that is much better at handling higher frequency. This switch close the loop allowing current to pass through your heat bed, if the temperature is reached or above, this switch opens the circuit and the current stop flowing.

If your model use mosfet (basically an electronic switch) instead of a mechanical relay, it would explain why your heat bed flickers with its LED.

By the way did you put that 4.7k ohm on your board? The whole idea of measuring the temperature with a thermistor is basically a voltage divider.

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Not sure about the 4.7k ohm. I purchased the Arduino Board and Ramps 1.4 as a completed set. Got it here: http://www.ebay.com/itm/151503265273...%3AMEBIDX%3AIT

I read a couple other things on internet about the 4.7k vs. a 10k (I think it was 10 or maybe 100). I wonder if Marlin thinks I have a different value?

That could be worth checking, changing the resistance will make an offset in your tepmerature.

Also, do you happen to have your printer in cold room?

Printer is in my garage and its 72+ F so i don't think thats the issue.

I got it to work! Main issue I believe was my hotend was flush against the heatsink and that wasn't allowing it to heat properly. I also had to run negative to pin 3 on my MK2B bed intead of just pin 2 (1 is positive).


Thanks for your help.