Upgrading a NopHead Mendel90 to an E3Dv6
I recently had the pleasure of visiting the TCT 3D printing show and meeting the E3D guys and their new hot end close up. I’d always fancied getting one and seeing it was enough to persuade me 
Wiring it up
One of the things you need to do when changing from a J Head to an all metal hot end is provide 12v to permanently run the hot end cooling fan. The NopHead Mendel 90 uses switched negative on the regular fan and heater, so one way is to take the positive feed from those and find a ground.
I took a look at the wiring methods people were using online and discovered many of them were using the ground from the temperature sensor. I checked this method out and found that due to the resistance of the ribbon cable, the ground was pulled up by as much as 30mV when the fan was running, which I calculated could cause an inaccuracy of up to 10 degrees C on the sensor. This didn’t sound good so instead I decided to run a separate ground using the unused pin in the D-plug (which was originally connected to the RPM wire on the print cooling fan).
A quick modification to the PCB and a new ribbon (to get the extra wire) meant that I now had a separate ground and a new hot end fan connector (which you can see in the photos). (As an alternative you could also use the right hand Z probe (P) pin which is included on the standard ribbon and left unconnected at the board end but I decided I wanted to keep that to add a Z probe at some point.)
Cooling the prints
The next problem I had was the original NopHead duct which cools the print by blowing air around the nozzle didn’t fit. The E3D was longer and wider than the J Head which meant a new duct had to be designed. So I knocked one up in 123D Design and printed it out in Bridge and mounted it to the carriage.
Firmware
Finally after changing the the E3D you have to do a few tweaks to the firmware. These are well documented on the E3D site so I won’t go into too much detail other than to say I took the opportunity to migrate to the current version of Marlin rather than using NopHeads version (which he keeps a few versions behind for stability reasons). This was a lot harder than expected but I got it sorted in the end and I now have a fully working E3D
Results
I have to say the J head supplied by @nop_head served me very well. The print quality was good and I never once had a jam which wasn’t easily fixed even when printing Laywoo-D3 (which was pushing my luck on a 0.4mm nozzle). However if you can afford it the E3D does take things a step further. The print quality is improved and the ability to change nozzle sizes really opens up your printer to a whole new world.
If anyone wants any further details on anything let me know below. I’ve kept it brief above so its palatable
