Hardward error 0502 comes on when printer is turn

The problem is simple. The Shiny Silver bar that your Print Cartridges glide back and forth on is the PROBLEM!!! When the motor that moves the cartridges left and right HAVE TOO MUCH RESISTANCE, YOU GET THE HARDWARE ERROR: 502. How I fixed it is simple. Take some kleenex, and with power unplugged, clean the bar very well. Then Spray some WD-40 on a Kleenex, and lubricate the shaft!!