I am having a very strange issue with my Printrbot Simple Pro with heated

3D Printing
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1

I am having a very strange issue with my Printrbot Simple Pro with heated bed. When using t he cloud slicer, the heatbed is not an option. But as soon as I start printing, the heatbed is turning on and running at its maximum. @Brook_Drumm1 do you have any idea what the heck is going on? I got lucky and noticed it before a fire started the first time, but the bed was so hot that the PEI surface became unstuck and the glue liquified. Any help or ideas form any one would be greatly appreciated.

Thanks in advance.

2

I’d also report this to their official support channels before someone gets hurt.

3

Sounds like the FET that controls the heated bed has fried. I would not use the main board unless the bed is disconnected.

4

I was thinking it was related to a Mosfet. I have already disconnected the heated bed, I rarely use it on the Printrbot. I do have heated beds on my 3 Di3’s and 2 Tronxy X1’s so it is not a big deal.

5

We can replace the board. See if that’s the issue. Drop me a line.
Brook

6

Thanks Brook, I’ll send you an email.

7

Sounds like a failed FET to me. Board replacement should fix that.

8

Shouldn’t thermal runaway protection detect that?

9

I have never heard of this, btw. That’s why I want the board. The firmware monitors runaway and shuts it down of course

10

The MOSFET likely failed like mentioned above and shorted to + 12V, in other words it became a stuck on switch. Not possible to fix in software (think of it becoming like a piece of wire). That’s one reason why you never leave your 3D printer unattended (web search 3D printer on fire) and never ever go to bed while printing.

11

Failed MOSFETs have been reported for years, including on Printrboards (no more likely than any similar controller) on the unofficial http://printrbottalk.com. Pretty easy to replace a through hole version if you can solder. Printrboards have the extruder and bed MOSFETs close enough they can short together with rough handling, fixed by physically separating them (any parent if multiple kids knows this one)