ABS model, Bed not heating

Hi friends, im from Mexico, i recently unboxed my R1 Abs model.

my problem is very similar as our friend from Australia (beautiful country)
http://forums.robo3dprinter.com/index.php?threads/heated-bed-not-heating.868/#post-3776

i read all the post and have no luck.

firstly, im working on "matter control" that came with the printer, but it didn't works as well on my mac (OS MAVERICKS) so i installed parallels windows and try on it, the UI connection works perfectly, but the Bed temperature remains at 0ºC, i checked the two Wires plugged in the D8 port and it seems to be ok (red wire at the left and black on the right side).

When i turn on the bed, the Red light doesn't appear, but when i turn on the extruder the red light turn on as well.

Do i missing something or my printer is out of order? Please Help!!!!! (sorry for my bad english)

 

A reading of 0 means that the thermistor has an open circuit.

This might be as simple as your thermistor came unplugged form the ramps board. Follow the thermistor from T1 to the bed heater checking to see if there's any breaks. You can also measure the resistance across it as you're looking for around 100kohms of resistance at 25C.

 

Hi

Mike: thanks for the quick reply, i will try right now and look for any break, i will post the result as soon as i end the checking up.

 

Hi friends

I already checked up the thermisor cord from T1 to bed heater (i removed the black protection spiral thing) but i didnt find any break.

unfortunately i can measure the resistance right now (i dont have the machine to do it) i´ll try to get one tomorrow, meanwhile, is there another thing i can do to solve this non heating problem?

 

Nope, the issue is in the thermistor. Find the open circuit and you'll fix the problem.

 

Ok but, if the wire is not broken, i think that the thermisor is out of order, isnt it? im an 3d model artist so i dont know too much about conections and electronic boards, ¿do i have to replace the thermisor cord? where do i can buy it? which is the exact model or how can i ask for it in a shop?

i uploaded a photo that i take (the withe sheet is only for get better contrast in the photo) so there you can see that the wire looks well. does it matter the way i plug the thermisor? black cord at the left pin or viseversa?

in case i have to replace all the cord, do i have to unplug the wire from the bed? because it is sealed by a red previous melted plastic.

 

It could be a bad thermistor sure. I've broken 3-4 semitec thermistors already so it's not hard to do. You'll need to follow the cable all the way to the thermistor attached to the board and see if there's a loose connection.

If your thermistor is broken, you can use the technical support request on the robo3d main page to have them ship you a replacement.

Polarity doesn't matter when connecting the thermistor as long as it's on T1.

 

when we are talking about the "thermisor" then we are thalking about the Wire, right?

im comparing the extruder thermisor and the bed thermisor wire and i can see that the bed wires (black and red) at the end of the plug (if removing the black plastic thing to plug it) that the wire is shorter than in the extruder thermisor, could it be the problem? may be i can peel the cord.

that kind of semitec thermisors are easy to be found at shops or only robo3D could provide it? are there generic thermisors or it must be from especific brand?

 

The thermistor is the little "Glass bead" connecting the two wires together.

Its essentially a ceramic material that drops in resistance as temperature increases. Also referred to as a NTC (Negative temperature coefficient). This is why an open circuit (infinite resistance) is equal to 0C, and a closed circuit (No resistance) is the max temperature, or ~300C.

The thermistor is very common, Semitec 104gt-2, and run around $5 per. Team robo will ship you one for free under the warranty.

The length of the wire doesn't matter. All that matters is the thermistor is properly connected to both black and red wire.

 

jajajaja, so it means that i was looking in the wrong direction.

where does the thermistor is located? i cant see that kind of "Glass bead" in the path of the T1 wire

the problem must be located from T1 to the bed wire? or it could be in another wire that may be are unpluged?

once i know where the thermistor is, i´ll ckeck it and fix it.

Mike, thanks tnaks for the help.

Do i have to remove that red previous melted plastic located under the bed? does the thermistor is covered by this red thing? jajajaja sorry i dont know where the thermisor is, i´ll upload a photo to show you what i mean when i say "red previous melted plastic"

 

The melted plastic is actually high temperature silicone used to transfer heat more evenly to the thermistor as well as secure it in place. This is very similar to what they use and what many of us use: http://www.amazon.com/Permatex-81878-Maximum-Temperature-Silicone/dp/B0002UEOPA

This is where having a multimeter for measuring resistance will be helpful.

Looking at the picture nothing jumps out at me as being broken.

Looking at the schematic of the ramps 1.4 board we're using you can see that the heated build plate (HBP) has one thermistor line running from it to T0 on the ramps board.

This is the only thing that measures the bed temperature. You won't be able to heat the bed until you have a working thermistor.

On your thermistor like there are 4 failure points, 2 per line.

Ideally the failure point will be at one of the two solder points that connect the red or black cable to the white thermistor lead cables. If it's not one of those then the thermistor leg broke off from the glass bead. This is next to impossible to fix, so you'll need a replacement.

Don't go pulling things apart until you get a multimeter and measure the resistance across the thermistor. That will be the sure fire way to see if it's working.

 

Thanks Mike, i will get a Multimeter tomorrow, then i´ll be cheking the resistance across the thermistor and i´ll be posting you the results in order to know if i have to replace the thermistor or it was only a bad solder point.

thanks for the support and i hope you could help me tomorrow. nice day.

cheers.

 

When looking for a multimeter don't just buy the cheapest one. If you get one that measures continuity it usually has any other features you'll need. The continuity mode is labeled as a diode symbol with a signal symbol above it. The dial is set to continuity in the attached picture.



Sent from my XT1060 using Tapatalk

 

I'm running into the same sort of problem. I was doing a print with ABS and the bed temperature started to fluctuate, slowly getting cooler. I tried another print the next day and the bed would not heat at all. I checked the wire connections and they seem to be OK.
Any ideas?

Cheers,
John

 

Hi friends, and thanks for replying, i just solved the problem!!!!!

Mike and Solong was right, the termistor was "unpluged"

I had to disassemble the bed, i was about to remove the silicon when i realized that one of the cables was disconnected from the welding, then i remove a little part of the silicon in order to weld the cable to the termistor (just after make the proper test with the multimeter i got, numbers were very low, 1.5 more or less).

After the welding, i tested with the multimeter again and the numbers were about 9.8 (something like that, cant remember), then i assembled the bed to the printer, powered it up, and BUM!!! the temperature of the bed was detected

immediately by the software!!!!
So, Sarge5020, i recommend you to check very closely the welds, that was my problem, just a disconected wire.
Here you have an image that shows the unpluged weld.