1 Topic by pascal

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Topic: Bed will not heat

I am having the strangest problem...after successfully printing something yesterday, I turned off the heat to both the nozzle and the bed for awhile, then turned the heat to the bed back on in order to print something else out. And the bed would not heat *at all.* It just fluctuates between 16.0 and 17.0 degrees. The nozzle still heats up no problem, but the bed--not at all. I'm pretty sure it's a hardware issue, and not a software issue, because the bed refuses to heat up in either RepetierHost or Pronterface. Does anyone have any advice? A quick google search did not bring up anything helpful. Thanks.

2 Reply by jagowilson (edited by jagowilson 2014-10-19 23:47:50)

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Re: Bed will not heat

Make sure it is connected to the motherboard. Its connector is the red wire on the left side of the board toward the back of the case. It is only 2 pins. Failing that, I'm not sure. If the board failed there, it would likely be always heating, as opposed to not at all.

If it is connected to the board, and you're certain it is tight, use a multimeter to check the resistance of the heating coil. I don't know what it should be, but you want to make sure it is not an open or short circuit.

3 Reply by pirvan (edited by pirvan 2014-10-20 16:07:01)

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Re: Bed will not heat

There are 2 possibilities:

The power MOSFET is burnt, or the bed heater is. 

You can do a simple test to see if the bed heater is still functional.  Simply unplug the bed wire connector from its current location, and plug it into the pin connector for the hot end.  Then in Repetier (or PronterFace) turn on the hot end.

If the bed heats up (you should see the temps go up and feel the the surface), then the problem is the MOSFET.  You can replace it with an equivalent or an upgraded version (some soldering required).

If the bed still doesn't heat up, then the heater is toast and you need to replace it.  There are many option, so do some searches to find a suitable replacement.  I for one use an MK-2A PCB heater.  It works quite well, but you'll need to upgrade the PSU to make it work efficiently.

To print or, 3D print, that is the question...
SD3 printer w/too many mods,  Printrbot Simple Maker Ed.,  FormLabs Form 1+
AnyCubic Photon, Shining 3D EinScan-S & Atlas 3D scanners...
...and too much time on my hands.

4 Reply by pascal (edited by pascal 2014-10-21 00:34:54)

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Re: Bed will not heat

Thanks for the helpful replies, jagowilson and pirvan. I checked the connector, as you both suggested, and there does appear to be a problem. If you look at the attached photo (or, if attachment isn't working, go to https://dl.dropboxusercontent.com/u/278 … t_heat.jpg ), you see a significant brown color in the pin connector--I'm guessing that means something burned out? Furthermore, when I try to disconnect the wire from the two pins, I can't seem to get it to come off. Is there some trick to getting it off? (The one next to it simply slides off when I pull down on it.) This may be further evidence that something burned out.  Is this possibly the MOSFET you mentioned, pirvan?

5 Reply by jagowilson (edited by jagowilson 2014-10-21 00:34:47)

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Re: Bed will not heat

Geez, how old is your printer? If this is a new printer Solidoodle should send you a new mobo--there's no reason you should have to solder. Is this an SD4? What is the. deal. with the mobos.

Anyway, sounds like MOSFET, but there's no attached photo. What's strange to me, though, is that usually when MOSFETs die, they  stay ON, not off. Fix the attached picture, it will help in assessing the scenario.

6 Reply by pascal

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Re: Bed will not heat

I tried attaching the photo, but for some reason it doesn't show up. I posted a Dropbox link instead. Unfortunately my printer is an SD3 that's over a year old--definitely not under warranty. And what is a mobo? I take it this is a common problem?

7 Reply by jagowilson (edited by jagowilson 2014-10-21 00:46:03)

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Re: Bed will not heat

pascal wrote:

I tried attaching the photo, but for some reason it doesn't show up. I posted a Dropbox link instead. Unfortunately my printer is an SD3 that's over a year old--definitely not under warranty. And what is a mobo? I take it this is a common problem?

Oh okay. Nevermind. Mobo = motherboard, where everything is attached.

Well, you either have the option of soldering or upgrading your board, if the mosfet is in fact what's wrong. Someone else may have more insight than me. No, this is not a common problem, I'm just having troubles of my own with my SD4, but its clearly unrelated smile

Really burned out though, damn! Some nice brown marks... lol. If you manage to get it off, you could check those pins with a multimeter, but be very very careful- they are extremely close together. I'm reluctant to recommend this though. Wait for the advice of someone else.

8 Reply by pascal

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Re: Bed will not heat

I'm a relative newb with both 3D printing and electronics, so I'm confused by your referencing "the" MOSFET. Aren't MOSFET's simply components used to construct transistors, so that there would be gazillions of them within the motherboard? Dumb question, no doubt, but I'm trying to understand everything I can.

Sorry to hear that my problem doesn't help you out with yours--good luck all the same, and thanks for the help!

9 Reply by jagowilson (edited by jagowilson 2014-10-21 01:18:00)

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Re: Bed will not heat

See the things sticking up right next to the extruder heater and bed heater pins? Those are the MOSFETs. They come in all kinds of sizes and are used for a variety of purposes. The ones on the board are big, you'll notice they carry a lot of power because they have little heatsinks on the top. Wikipedia for more information if you're interested.

10 Reply by MacGuyver20

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Re: Bed will not heat

So I had the same problem where the bed would not heat up.  After a lot of forums and information and tinkering I found out the original heat beds were not designed to go above 80 C.  I burnt mine up.  But I replaced it with a MK2a bed.  I also had to replace the Power supply 360w 30A.  The final product is so worth it.  I have not had a single warping issue and or bad print due to sticking since. The price for the bed and powersupply $40. 
I also use a glass bed on top, with ABS glue (Acetone with ABS mixed in)

I also added an enclosure and replaced the standard sliders with a more rigid ball bearing setup.

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11 Reply by jagowilson (edited by jagowilson 2014-10-21 21:41:49)

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Re: Bed will not heat

Nice work! By sliders do you mean the Y rod in the back? I kinda wanna replace the bushings in mine with ball bearings. How did you do it? I'm not sure how to remove the existing bushings or how to correctly fit the bearings in the holes on the side. Considering doing the other bearing mod, but I'd feel so much more pro replacing the bushings.

12 Reply by pascal

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Re: Bed will not heat

Thanks for the advice, MacGuyver20. Anyone have any recommendations for how to get the pin connector off the motherboard? I'm afraid I just rip it off I'll do some damage...

13 Reply by jagowilson (edited by jagowilson 2014-10-24 04:44:06)

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Re: Bed will not heat

You will probably have to desolder the header from the motherboard, unfortunately. When I blew my MOSFETs from shorting my old board, the bed heater header pins fused with the contacts in the molex on the end of the cable. If this is what happened in your case then there's no way around it, you'll likely be cutting wires, crimping a new molex on and soldering a new header.  Sucks. Any other option really isn't safe unless you want to take this time to do a motherboard upgrade. The heaters carry a lot of power, which is why they are the thickest wires in the printer. Salvaging the current board will require soldering no matter what avenue you take, because at the very least you have to replace the MOSFETs.

14 Reply by pascal

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Re: Bed will not heat

Got it. Thanks, jagowilson, I really appreciate all the help!

15 Reply by pascal

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Re: Bed will not heat

Update: I was actually able to pry the connector off of the motherboard with a pair of pliers, and--miraculously--it appears that the mother board is not damaged. I just need to replace the connector from the heat bed to the motherboard, which Solidoodle's support is offering to do. I'll post back with how this ultimately works out...

16 Reply by n2ri (edited by n2ri 2014-11-04 02:55:49)

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Re: Bed will not heat

did you check wires hanging from board to heater under bed? likely when print ended and bed lowered for removal a wire connection failed is all. those wires wont flex forever without cracking either at an end or inside insulation at a bend like mini chrismas lights do after a few uses and being re-wrapped for storage.

Solidoodle 2 with Deluxe kit cover & glass bed with heater. and 2nd board SD2 used not 3rd and alum platform not installed yet still wood. also need cooling fan installed to board. use Repetier Host couple vers. Slic3r also have all free ware STL programs

17 Reply by pascal

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Re: Bed will not heat

Thanks for the advice, n2ri, but I'm quite certain the problem is a burned-out connector to the motherboard. Check out the photo in the dropbox link earlier in the thread to see the evidence :-)

18 Reply by pascal

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Re: Bed will not heat

Hey MacGuyver20, would you mind sharing where you purchased your MK2a bed and power supply? I'm seriously considering using this as an opportunity to upgrade my bed as you suggested. Thanks.

19 Reply by n2ri

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Re: Bed will not heat

pascal wrote:

Thanks for the advice, n2ri, but I'm quite certain the problem is a burned-out connector to the motherboard. Check out the photo in the dropbox link earlier in the thread to see the evidence :-)

yeah saw that after posting but figured it may help others trouble shoot as it is another possibility of failure.

Solidoodle 2 with Deluxe kit cover & glass bed with heater. and 2nd board SD2 used not 3rd and alum platform not installed yet still wood. also need cooling fan installed to board. use Repetier Host couple vers. Slic3r also have all free ware STL programs

20 Reply by blarz

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Re: Bed will not heat

How is your board holding up with the new mk2a heatbed? I have already updated my power supply as the original died a month after receiving the sd3. So that part of the equation is covered. I'm just wondering how your board is holding up, also did you have to place a thermistor under the board to register temps? I have an mk2a board here, for another project, currently collecting dust and I'm afraid of burning out my board with connecting it directly. My sd3 is using the sanguino board. Any help would be greatly appreciated.

SD3/SD4 Mods completed: glass bed, changed zrod to 5mm, slop nut, aluminum arm-originally wood, plexi-glass case, Z Wobble Preventer,  Lawsy Carriages, X\Y motor fans, control board fans, extruder cartridge heater, MK5, Esd Lite
Mods working on:Direct Y Drive
Remember.......All you touch and all you see is all your life will ever be....Pink Floyd...Dark Side of the Moon.