wherein {TAIL ~ said step} of installing said circuit board includes a step of mounting {HEAD ~ said circuit board} on said rear tray 
wherein { TAIL ~ said step } of installing said circuit board includes a step of mounting { HEAD ~ said circuit board } on said rear tray
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH