I have been having extrusion problems ever since I upgraded my stock mk10 extruder gear to the mk9 gear used in the Duplicator 4 as is suggested to combat filament slippage/grinding.The results were mixed. No longer was I experiencing slippage of filament, but I could also no longer extrude as quickly as I once was. For example, using Repetier Host Server I would extrude 100mm of filament after a filament change to clear the old filament from the extruder. Whereas the default speed is 2 mm/s I could never extrude that quickly with the mk9 gear. I would have to slow it down to the lowest speed of 1mm/s.During prints that used rafts I would often get a “thunk thunk thunk” indicating that the stepper was not able to extrude the needed volume.And I would experience random layers that exhibited under-extrusion.Generally I just needed to slow everything down to make sure as much as I could that I would not under-extrude. I finally got tired of it and did some research on the issue.Apparently the Di3 V2 steppers are different from the V1 and using lower voltages, but Wanhao factory didn’t adjust for the lower voltages. After figuring out what I needed to do I took apart my control box, unplugged the Melzi board and got to work testing the voltages. Sure enough the voltages were set too high: X 0.720, Y 0.697, Z 0.738, Ext 0.718. What they should be is X & Y 0.45, Z 0.6, Ext between 0.45 & 0.54.I adjusted the pots and put everything back together. I loaded in some filament and extruded at 2mm/s on Repetier Host Server with no thunking. Right now I’m printing my first print and I can already tell with the first layer that it is extruding more consistently.So, Di3 brothers, check your voltages. I’ve no idea if this affect successor versions of the Di3 v2.Here are the resources I used:http://ift.tt/1tyLHpJ it may make sense to go by my voltages, please, please, please verify. I neither claim to be knowledgeable of this stuff nor claim an IQ above 100.BTW, the printer is quieter as well. http://ift.tt/1XspjKe