Berd Air and Einsy-Rambo (Prusa MK3)

[jakevsnake]

So I got my Berd Air setup and the e-switch kit installed tonight and took it for a test run.  I followed the PDF for the Berd Air and Duet as it seemed to be the way to go for my setup.  I put the diode between the terminals on my pump reversed biased as instructed and had 24V going to the positive terminal on the pump.  I then hook the output 'O' from the e-switch cb to the ground on the pump.  I fed a common ground into the cb and then tapped the negative from the fan header into the 'L' (LOW) on the cb.  When I went to turn on the "fan" nothing happened.   I took some readings with my meter at the pump and got no voltage..  long story short, I then bypassed the circuit board entirely and tapped the negative fan header straight to the negative on the pump.  Bingo, it worked... i could control the fan speed the same as I could the stock cooling fan..

The only way I could get it to work using the e-switch was to plug the negative of the pump into the 'L' at the top of the cb.  What is this e-switch supposed to do exactly? 

[jakevsnake]

Ok, so one thing I missed was connecting 5VDC to the circuit board. That explains why my motor would not come on at all, but it does not vary the speed. From what I have figured out, this is not a PWM fan header. When I connect the motor to 24v and then connect the negative to the negative on the fan header, it varies the voltage based on my inputs on my LCD. So, it appears this e-switch was unnecessary for my application. My B.E.E knowledge is a bit rusty as I have not had any use for my schooling over the past 24yrs 20yrs as an avionics technician in the Navy was spent working on aircraft, not troubleshooting things down to a component level. I was relying on info I was given that this was a PWM application.. live and learn

[BeeAmaker]

If you want to connect the pump directly to the Fan output, Check with your board manufacture that the fan output can handle over 1 amp. The pump, over time, could cause the MOSFET on you board to over heat. This is the purpose of the eSwitch. It allows you to connect a heavier load to the fan out. If your eSwitch wasn't passing the PWM through, then it's possible the MOSFET on the eSwitch is damaged (they are static sensitive) or there is a bad solder joint. Usually the MOSFET will damage in the full on position.