Wanhao i3 / Monoprice Select Essential Modifications

The Monoprice Maker Select V2 is a rather decent $329 USD printer out of the box. Most of the initial complaints such as the wingnuts on the bed being difficult to adjust, the control board heated bed connector melting and smoking has also been resolved in units now shipping from Amazon.

Most of the community from my experience still recommends adding an external heated bed MOSFET as they don’t trust the melzi board to handle the current pulled by the bed. Personally I feel as if the upgraded board with the new connectors can handle the stock bed current just fine with the stock setup, but I still upgraded to the beefier XT60 connectors anyway as I ordered them.

EDIT, apparently the upgraded factory connectors still melt. It may be best to grab an external MOSFET to be safe. Thanks Darron of the i3 FB Group.

To fix reported temperature fluctuations of the hotend, solder a wire from the negative MOSFET terminal of the hotend to ground.

Not bad for some of my first soldering work, eh? The next modification was to rotate the extruder stepper motor so the wiring harness doesn’t hit the top frame to get the full 180mm of Z axis travel. I extended the wiring harness.

You may be able to get away with rotating the stepper motor to the rear without extending the harness, but sadly I didn’t test that mounting orientation before performing the modification.

Here’s a Z axis extension mod, which should help without having to do any soldering on Thingiverse. Thank you Uwe from the Wanhao i3 group!

Image credit AzzA

The next mod you’ll want to do is to print off these Z axis braces, order some threaded rod (cut to size) and nuts, including nylon nuts. This is one of the more important mods you can make, as the factory weak Z axis can cause Z axis wobble and inconsistencies in your prints.

Image thanks to Mark West AKA wakeryder http://www.thingiverse.com/wakeryder/about

By this point, you’ll have a rather solid 3D Printer at low cost and relatively low time investment. There are however two more modifications I can recommend for the 3D Printing novice or anyone looking to easily further print quality, choice of materials and ease of use from this point. The first one would be the MicroSwiss All Metal Hotend.

An all metal hotend will allow you to print with higher temperature materials, provides a more consistent melt chamber control and helps prevent stringy prints. The quality of this part is outstanding in my opinion. Here’s the installation brought to you by Joel, the 3D Printing Nerd.

The next modification replaced the factory flimsy bed carrier plate. I noticed that between prints that I’d have to level the bed again (especially if I applied any force to the bed to remove a print). I ordered this full alloy build plate kit with an upgraded heater. The bed carrier plate is as thick as the factory build plate itself, greatly stiffening up the carrier plate which leads to the bed staying level between prints.

Note that if you use the included bed heater, you will want to install the external heated bed MOSFET as the heater pulls more current and the stock board may not be able to handle the amperage safely, or at the least will decrease the lifespan of your melzi board.

I also replaced the bed springs with stiffer ones to provide a more secure bed adjustment range without the adjustment wheels turning while printing and to further stiffen the build surface. As metal flexes when heated, a glass plate will stay level while printing. This is the best glass bed holder part I’ve found so far on Thingiverse.

Image thanks to surewhynot http://www.thingiverse.com/surewhynot/about

Stay tuned for my next post where I upgrade to a E3D Titan Extruder with E3D V6 hotend, add a BLTouch for auto bed leveling, redo the factory wiring, swap the PSU for a Meanwell 350W unit, install a Smoothieboard and much more!


    1. Thank you! I’m going through the final config changes and testing now. I’ll also need to make sure I have plenty of awesome images for the next post.


  1. I’ll be doing the E3D and Titan as soon as my parts get here. I’ll be interested in seeing how you do the install.


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