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