Step1: Disassembly the printer to the package status when it comes.
Step2：Take out the Z axis head printable cover by twisting off the 2 screws on the top of the linear rail.
Step 3,Take out the limit switch by pulling it up after twisting off the 2 screws fixed the switch.
Step 4. Take out the circuit board on the back of z axis and unplug the limit switch cable .
Step5. Then the limit switch was taken out fully.then replace the new limit swtich according to the reversed process to finish the replacing.