After using my Mosaic 1 printer for about 6 months, my filament drive wore out. This was caused by my PTFE filament guide not being aligned perpendicular to the filament drive. Long printing sessions wore a groove into the filament drive and eventually the filament was forced to the side of the drive gear. The symptom of this problem was a slow degradation of grip on the filament resulting in inconsistent printing.I tried adding a frame mounted filament guide (http://www.thingiverse.com/thing:23748), but this was not sufficient to keep the PTFE guide tube straight over the filament drive. This part has solved my problem.Print the guide. Remove the filament drive tensioning bold. Insert the guide and re-apply the bold. Thread the PTFE guide tube through the guide.