Those of you with Creality 3D printers have probably experienced the problem of the controller board getting power through a USB connection when the printer is turned off. The display remains on and a high pitched whine can sometimes been heard. It turns out a small piece of tape carefully applied to the USB connector can solve the problem. The image in the following link shows Kapton tape, but I was able to use Scotch tape.
This is a good update for the Ender 3 also. better tube(Capricorn) for less wiggle room for the filament in the bowden and higher temp. Kit has good fittings on each end and you do the hotend fix by 3d print the little spacer and cutting guide so that hotend back pressure doesn’t push back on the bowden line/connector. After the upgrades my retraction setting went from 6.5mm to 3.5mm.
video and links on how/why to do the hotend fix. Simple HOTEND FIX for Creality Ender 3, CR-10 - YouTube
I used this Thing for the cutter and the spacer - Original Hot End Fix Creality , Tevo Tornado, Tronxy, JG Aurora, Eryone ThInker by L3D_Help_Guide - Thingiverse