Fix for creality ender 3 pro v1.5 lcd selecting random menus.
Recently my wife gifted me the Ender 3 pro v 1.5 with the 4.2.2 mainboard. after building the machine which was very easy and only took about 30 minutes as the majority of the parts were already assembled.
after printing a few upgrades the lcd started flipping back and forth between the different menu selections.
looking for a quick fix i ordered an emi filter from another website but they sent me the wrong part and i had to wait for the correct part. in the mean time i broke out the multimeter and started testing connections. when i started checking grounds from the ground on the power cord to the various parts of the machine i noticed an issue. there was no path to ground from any part on the machine except the mainboard and while examining the lcd i found there were copper circles around the screw holes in the circuit board. after looking at the standoffs on the back side of the mounting bracket i noticed the really nice job they did on the paint. unfortunately they failed to mask off the standoffs so the lcd was completely isolated from ground. after checking i found that the sepper motors and x and y axes were also isolated. to fix the issues i connected a 14 guage wire from the earth ground terminal on the power supply to one of the screws on the lcd mount. next i ifollowed the wire harness to each component and axis with a ground wire and tied them all into the now grounded base. i checked all components and axes for connectivity to ground then fired it up. while homing i noticed the screen was still flipping between menus but not as bad then i realized that i had forgotten the standoffs. i broke out the dremel with a stone and took the paint off of the tops of the standoffs .
once the lcd was put back on and connected the machine has been a juggernautrunning job after job without any issues.
so poor grounding is a definite issue but it is easily remedied with a little determination.
@blacksteinkopf i ran a wire from the earth ground terminal on the power supply to the bottom screw on the lcd mount to ground the bottom frame. then i ran wires from a screw on each axis and tied them all together with an added screw in the back left of the bottom frame. the bed is grounded by connecting the wire to the back left corner bed screw. the display is grounded through the standoffs which is directly connected to the bottom frame and earth ground. dont forget to sand or scrape the paint off of the standoffs under the lcd so they make contact with the copper circles around the screw holes. after that you should be up and running. all of the ground wires can be run through the wire loom on the wire harness for a cleaner setup. do not ground the controller board as it runs on dc power and already has a tie to ground through the negative power terminal. you could just run a wire to the outside housing of each stepper motor as they are directly connected to the axes. dont forget to run one for the hotend carriage as the rubber wheels isolate it from the x axis.
Dear Kitorkim, how are you?
My Ender 3 Pro has the same problem. Could you share your solution? I didn't quite understand how you made the GND connections. Have you connected the GND of the PSU, the Creality controller card and the LCD card to each other? Then, did you connect that GND to the printer housing (after removing the ink from the circuit board holders)?