AT&T MERLIN LEGEND Communications System Release 2.0 Maintenance And Troubleshooting Manual page 95

Control Unit Problems
Replacing the Ring Generator
WARNING:
Hazardous electrical voltages may be present if the following steps
are not performed correctly.
Follow these steps to replace a ring generator (see Figure 4-2 throughout this
procedure):
1. Make sure each power supply is turned off, including the module in the
control unit and any auxiliary power units.
2. Unplug the power supply cord from the AC outlet (or from the auxiliary
power unit) and then from the power supply.
NOTE:
At this point, all cords should be removed from the power supply.
Remove the power supply from the carrier.
3.
4. Place the power supply on its left side and remove the five screws.
Carefully turn the module over on its right side and then remove the top
5.
of the power supply housing.
6. Detach the cables from the inside edge of the plastic housing by
removing them from the clips.
7. Disconnect the 4-pin cable from the header labeled P202 on the left
side of the power supply circuit board.
N O T E :
As shown in Figure 4-2, you may need to pry back the clip to free
the cable.
Power Supply Problems 4-5