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3D Printer / CNC discussion thread

sswilson

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I don't need it, but saw this on thingiverse and thought it looked pretty cool....

 

danmitch1

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Dec 15, 2007
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Hey guys, my heated bed and hotend mosfets died on my skr mini. Second board to have dead mosfets from btt, but this time its off warranty. Im gonna just go the external mosfet route. Do you need to change anything to the firmware when using external mosfets?
 

lowfat

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Hey guys, my heated bed and hotend mosfets died on my skr mini. Second board to have dead mosfets from btt, but this time its off warranty. Im gonna just go the external mosfet route. Do you need to change anything to the firmware when using external mosfets?
BTT has some real QC issues it seems. If you want to use external mosfets on that board you will need to solder wires to the existing outputs on the board. I don't believe the Mini has any open PWM pins you could use otherwise.
 

danmitch1

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BTT has some real QC issues it seems. If you want to use external mosfets on that board you will need to solder wires to the existing outputs on the board. I don't believe the Mini has any open PWM pins you could use otherwise.
Damn, I was afraid of that.. I have VERY little experience with soldering.

Can you tell by looking at this?
skr_mini_e3_v1.2_FS_drawing.jpg
 

danmitch1

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PC7 on the Neopixel connector will work for one. I use it for my hotend fan. Maybe PC6 on UART for the other.
And then, I would have to change the PIN in the firmware I guess ?

Edit : ( I suppose silence means yes or google it ! : P )
 
Last edited:

danmitch1

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Hmm, so i have an external mosfet hooked to the neopixel pins on my board (ground and signal). I have changed the fan pin to PC7 in marlin. When I set the fan to 100% I see the signal led on the external mosfet light up which to me says that I have it set up right in marlin but, the fan doesnt spin and rightfully so as I only see 1volt coming from the power out on the external mosfet. any ideas?

should I be focusing here?

/=============================== Extra Features ==============================
//=============================================================================
// @section extras
// Set number of user-controlled fans. Disable to use all board-defined fans.
// :[1,2,3,4,5,6,7,8]
//#define NUM_M106_FANS 1
// Increase the FAN PWM frequency. Removes the PWM noise but increases heating in the FET/Arduino
//#define FAST_PWM_FAN
// Use software PWM to drive the fan, as for the heaters. This uses a very low frequency
// which is not as annoying as with the hardware PWM. On the other hand, if this frequency
// is too low, you should also increment SOFT_PWM_SCALE.
//#define FAN_SOFT_PWM
// Incrementing this by 1 will double the software PWM frequency,
// affecting heaters, and the fan if FAN_SOFT_PWM is enabled.
// However, control resolution will be halved for each increment;
// at zero value, there are 128 effective control positions.
// :[0,1,2,3,4,5,6,7]
#define SOFT_PWM_SCALE 0
// If SOFT_PWM_SCALE is set to a value higher than 0, dithering can
// be used to mitigate the associated resolution loss. If enabled,
// some of the PWM cycles are stretched so on average the desired
// duty cycle is attained.
//#define SOFT_PWM_DITHER
 
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danmitch1

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Get it working? You sure you getting 24v to the mosfet?
Nah, I gave up on it. I tested the dc in and saw 24v on the mosfet. At least on this board, the bed and hotend mosfet work. As a temporary solution, I hard wired the part fan directly to the psu with a dishwasher power switch inbetween lol...

I contacted BTT support about the newer board with the bad bed and hotend mosfet, sent a video of me testing everything and they said it was indeed a mosfet issue. They then asked for my shipping info that they would forward over to sales but I havent heard since.. I guess I may see a new board in my mail box suddenly or sales noticed that this is a RMA unit that is passed the original units warranty.

Worse comes to worse, I bought a cheap soldering kit and will attempt to tap into the signal from the bad mosfets and see if that will work with my external mosfets.

Any tips on what I tap into? drain gate source? No clue what im doing lol...
 

Bartacus

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Nov 22, 2014
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Well I recently decided to change jobs. Which lead to a lot of depressing and unhappy thoughts. Thankfully I'm lucky enough to be in a position to move around, lots of people aren't that lucky. But still, leaving a near 20 year career in Canadian gubmint, just because Shared Services Canada is an absolute cluster-!@#$, I decided to cheer myself up by buying a new hot end, a Dragon high flow, special "Voron red edition", LOL!

38y6fmml.jpg


It's adorable:
aDaZu62l.jpg


This will go on my Ender 5 Plus, once I do the linear rail conversion. Up to this point, I have the parts for the conversion, but I still have some Z-axis issues. So I was on the fence about it, what to do. Why convert an E5+ to linear rails if the Z is still problematic? But then as luck would have it, I found this, and now my plans might change:


This guy designed a linear rail Z mod for the E5+, and I *really* *really* want to do this. It's probably way above my comfort zone in terms of modding, but this could potentially solve my Z issues for good, and will only cost me two more 450mm MGN12 rails and some 2020 extrusion, that I can source locally. Think it's time to up my printer modding game and get serious!
 

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