[Swansea Hackspace] REPRAP question - Yellow Fuses on RAMPS board overheating

[Peter Tangney]

Hi Richard,

I had the same problem with the large yellow polyfuse on my RAMPS board, so
I ended up removing it and replacing it with a bit of wire, which is a
pretty terrible idea, but it hasn't caught on fire yet. IIRC, the bed fuse
is rated at 12A, which should be plenty for your bed - what kind of heater
are you using?

In any case, to get the fan to come on before the bed heats, make sure you
add your M106 line before the line that says M190 S[temperature], which is
the G-code for 'wait for bed to reach target temperature'.

Peter

On 14 September 2014 08:34, Richard Morgan <richard.morgan at avocation.co.uk>
wrote:

> Hi All,
> I have a problem with my 3D printer and I hope you can help.
>
> *Blowing on the Bed*
> When I start a print the bed begins heating and gets as far as about 50
> degrees the stops and cools down again!
>
> Speaking with Ceri, he suggested it might be the big yellow fuses on the
> RAMPS board tripping out. I tested this by 'blowing' on the fuses while
> it's heating up and 'bingo' Ceri was right.
>
> *Fitted a Fan*
> So, I fitted a 40mm fan (wired to the D9 point) over the RAMPS board to
> cool it down (as it doesn't look that cool to be blowing on your board when
> people see you printing!). I added the "M106 S255 ; Turn on RAMPS Board
> cooling fan" code in the 'start G-code' section of Slic3r to start the fan
> when it goes to print.
>
> *Remaining Problem*
> Problem still is that the fan itself doesn't actually start (i.e. this
> command doesn't execute) until the bed has heated to target temp first -
> which is where it trips out the fuse. This means that I STILL need to
> 'blow' on the board until the bed has reached target temp and then the fan
> kicks in and cools the board itself fine!
>
> So short of wiring the fan to the yellow and black power on the board
> (rather than to D9) so that it's always on - is there another way to fix
> this problem please?
>
> All help very gratefully received :-)
>
> --
> Kind regards,
>
> Richard
>
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> Hackspace at swansea.hackspace.org.uk
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>
>


-- 
Peter Tangney
peter at peterland.net.nz
http://www.peterland.net.nz
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