I bought the Monoprice Select Mini 3D printer and promptly noticed a crack in the filament feed tray. I could have returned it, but I noticed a design flaw in the original. All of the spring pressure was focused on a single hole. This new design uses surrounding fasteners for extra support. I searched, but couldn't find a design for this part anywhere online. Hope it helps someone else out.
I got some feedback that the spring holder on the original was too low. I raised the spring holder by 1.5 mm for better alignment. I haven't printed it yet, but it is the v4 file if you'd like to give it a try.
Monoprice Select Mini 3D Printer
Resolution isn't that important for a functional part, but print at 100% infill for added strength. This is the 4th iteration of the design and should work straight from the printer.