4.1.2.4.1 Replacing the Control Board in 1+1 Protection Mode................................................................................ 524
4.1.2.4.2 Replacing the Control Board without 1+1 Protection Mode.....................................................................527
4.1.2.5 Replacing the PIC Board............................................................................................................................................ 529
4.1.2.6 Replacing the PIU Board........................................................................................................................................... 532
4.1.2.7 Replacing the FAN Board.......................................................................................................................................... 533
4.1.2.8 Replacing the Optical Module................................................................................................................................ 534