Bypassing a fried D9 MOSFET with RRD Fan Extender for PWM autocooling?

Hi all,

I had a minor incident with my printer which shorted the d9 MOSFET (and therefore I assume it's fried) on my RAMPS 1.4 plus. Since then I have been unable to control the speed of my layer fan. Neither repetier settings nor direct control through the printer change anything, so I'm left with an always-on layer fan running at 100%. Although usable, it's not ideal.

My options I see at this point, after doing some research, are:

A. Replace the irlr3103 MOSFET for the d9 on my board (which involves more detailed soldering than I've ever done and risks ruining my whole board)
B. Replace the entire RAMPS 1.4 plus board (which I'd like to avoid doing if I can simply replace a 10c piece)
C. Bypass the fried d9 pin entirely by purchasing an RRD fan extender.

Fan extender module link

Option C is what I'd like to do but I'm unclear as to whether fan speed can be software controlled through an extender module. I don't want to purchase a fan extender just to find I can't control the fan speed.

TLDR: Can layer fan speed be software controlled via an RRD fan extender module or not?

Besides an answer to that question I'd appreciate any input anyone has regarding the safety and feasibility of options A and C.

I already consider my heated bed mosfet as my backup. Since I dont use a heated bed, at least not yet, if anything happens to one of my mosfets I will definitely swap them in a heartbeat. Maybe I am a little more comfortable with it since I do a lot of soldering anyway but it should be very simple. I have already removed both fuses and a diode. I am much more protective of my Mega since I know fixing that if need be will be much more difficult or impossible. The Ramp is really just an adapter with a bunch of easily replaceable parts on it. I would just go ahead and do it, especially if you are considering replacing it anyway. As long as your reasonably careful your not going to fry your board, just disconnect it obviously, take out all you drivers to be safe, and there really are not any delicate electronics left to fry. As long as you have some extra drivers and 100uf caps laying around you should be able to keep that board going as long as you need it. Good Luck!

Sorry I don't know much about the fan extender.

Edited 1 time(s). Last edit at 01/13/2017 09:34PM by Draytology.