1.5 Hold the bottom case and push back (to input lines direction).
Fig.4
1.6 You will see the two metal cases. There is one screw on the PCB. Loosen it, then the whole metal case
can be taken out. There are two wires still connected with the upper case. Leaves them there.
Fig. 5
1.7 The metal case is illustrated as follows:
Fig. 6
2