Ramps 1.4 Mosfet Overheating "magic smoke"

[Joseph]

Ah i just received the firmware from Wang and upload it to the ramps 1.4 .

The printer work just normally, until in smell of burning plastic. THE MOFSET WAS SMOKING!! ( turn the power supply off ASAP) One of the port melted a little, however each time i turn the power supply the mofset start Overheating and a wierd white smoke comes out of the mofset, read online people call it "magic smoke".

I want to know what the course of action; will you replace the ramps 1.4?

It has been one month and half sence i received the kit and still cannot print anything.
considering this the third issue i get with the kit.

[zhangxueyou]

How do you mount the mainboard on acrylic board? Please take a picture.

[Joseph]

Like i mention 3 issue. mi first thread the leg where the instruction it was missing a set of holes. Solve, changing the arrangement of the holes. The only way it could be possible with the USB port facing direction. Notes the fan was not facing like the one on the instruction. I called in a favor and printed this part.

(the model is a fan mount top to the board)

However, suddenly when i start the printer on the power supply the Q3 started to smoke and the led turned on red (2 comopenent next to Q3)

So now i got his:

[Joseph]

I forgot one part in the intrcution doesn't rely explain by detail how to main it so i posted this week ago:

http://www.geeetech.com/forum/viewtopic ... 22&t=16138

So that how is monted.

[zhangxueyou]

As I say in the email, cooling the MOSFET is very important. If you mount the mainboard in other directions, the cooling fan will be vain. As you heat up the hot bed, the temperature of MOSFET will raise quickly, it need to be cooled down, or it will be burnt out like yours. You have to replace a new MOSFET now.

[mediaklan]

Sorry to bump into this thread, I have not yet totally completed the building of my i3 pro B, but I'm concerned about this problem as well. I'm using iduino mega R3+ramps1.4 and there are only two directions I can put the board. Either I put the board USB port facing the fan, which is impossible without removing the fan (and leaves very little place to actually connect anything in there), either I put the board USB port in the opposite direction, in which scenario the LCD/SD connectors will totally mess with the fan airflow (see picture below). Since I'm gonna used the USB port, I'm choosing this last solution, and I have planned to use a 92mm fan connected to a computer to cool the board (until I can print something like a board case to handle a cooling fan on top).

If one of you have a better idea, I'm listening !

[zhangxueyou]

This is how I mount the mainboard, use a screw and power cable to firm it.

QQ截图20150420142356.png (667.06 KiB) Viewed 22085 times

QQ截图20150416160855.png (487.88 KiB) Viewed 22085 times

[mediaklan]

Well done, at least your board fan do not seems as useless as mine
Are you able to fit your USB cable in there ? Mine can't fit if i put the board the same way you're showing here.

[zhangxueyou]

I always use SD card to print the model. Save the stl file as g-code file after slicer. Using a computer to print is electricity-wasting.

[Joseph]

see I'm not the only one with the problem ! The leg has problems with hole arrangement. If you saw the model mi friend printer it's a mount to put the fan over the ramps1.4. Like this