Extruder Won't Heat At All

I just received my printer today and have spent the last 5 hours setting it up. After reading through the forums and watching videos I have yet to see anyone else with this same issue.

The extruder will not heat at all. I was able to recreate this issue in both Repetier and MatterControl. The heat bed heats up just fine, and quickly at that. I removed the cover from the top of the machine to check the wiring to the extruder in detail and I cannot find any discernible issue. All wires seem undamaged and all connections all the way to the chip set are secure. The temperature of the extruder is able to be accurately read as it reacts to fluctuations in the ambient room temperature.

Any help would be greatly appreciated.

 

I have power. The fuses on the RAMPS are cold. The bed moves and heats properly. Also, possibly unrelated, there is a sound when the machine is turned on like vibrator that eventually gets so loud it's like I'm trying to land a small plane and only gets quieter if I re-position the bed.

Also, the LED on the bottom of the machine is red.

 

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I had to turn the printer off, unplug it, then unplug the connectors from the hot end. Plug it back in, turn it on, connect the printer to repetier, then reconnect the connectors and that caused it to work. AWESOME!

 

NO I DIDN'T!!! DAMN!

It just happened again, but at least I know the heating element works so it would seem there's a short somewhere

 

My extruder didn't heat up when it was homed at first - I found it was due to the cables being too tight underneath. If you look at the RAMPS board there's a pair of grey wires and red wires that were in the wire wraps to keep them out of the way. I took them out of the wraps so they're loose and found that got them to work.

For your vibration sound, my fan mount on the RAMPS board had dislodged during shipping and that caused a similar-sounding problem to what you're describing. Make sure it's clipped properly to the RAMPS board and the extra noise might go away for you too. If you still get it, I wonder if it's the power supply, in which case a replacement is probably best.

 

Thank you for your input. I Tried it but it didn't work, so I wrapped them back up.

Yes, the sound was the fan, but I still cannot get the extruder to heat up. I requested a replacement unit but I'm not sure if that's possible.

<rant>
I'm just really disheartened because I believe for the cost of these units they should arrive in good working order and not require all this fuss to set up. I'm a technical person. I work in the industry and attend CES every year, but to spend 3 days banging my head against the wall because my new $700 printer will do everything except print, is ridiculous.
</rant>

Here's a pic of my board in case anyone is interested:

 

Darrell,
I agree totally, this should not be happening, especially on the later delivery printers. Did you email Jerry at robo customer service?

My printer is a November delivery printer with no connector at the hot end so I don't know exactly what your's looks like. Can you probe at the hot end heater connector without disconnecting it? You need the thermistor intact or it will throw an error and stop heating. With a voltmeter you should see close to 12V, with a scope you should see a PWM 12V signal.

Did you double check the hot end thermistor connection at the RAMPS board?

Schematics and connector layout here:
http://reprap.org/mediawiki/images/f/f6/RAMPS1.4schematic.png
http://reprap.org/mediawiki/images/c/ca/Arduinomega1-4connectors.png
The whole this is really pretty simple.

 

I've quadruple checked.

And I've been in contact with Braydon

 

OK Darrell, please let us know if and how the problem is resolved.

 

No word from anyone yet, but I contacted technical support for good measure

 

I received a response from the great Barnacules via facebook giving me his take on the situation:

"Sounds like you either have a defective thermister on the print head or a defective arduino board where the relay isn't working properly. I would post your problem to the robo3dprinter.com forum since a lot of people on there are active and may be able to help you. I never liked the print head that came with the robo and that is why I went with a E3D and cemented a new thermaister and probe on to it."

 

The thermistor is probably fine if it is tracking room temp. Since it worked once intermittently I still would suspect an open somewhere in the heater wiring. It would be odd for the hotend MOSFET driver to not work, work then not work. Could be a bad header connection from the Arduino Mega to the MOSFET. Save a screenshot of Barnacules reply, that's pretty funny! What a man cave he has.

 

I tested both ends of the heater wiring with a multimeter and got positive tone for a closed wire circuit

 

Thanks Jerry this is really helpful to hear. BTW how many ohms do you expect across the heater cartridge or resistor? (with good crimps )

 

For those of you following this; Jerry has been awesome to work with and has sent me a new hotend. The suspense waiting for it is killing me

 

I am having the same problem where I think there is a lose connection but I just can't seem to find it.

 

Jerry had to send me a new one. It's working now.