User Manual

ADCP-75-158 • Preliminary Issue A • June 2003 • Section 5: Maintenance
Page 5-19
© 2003, ADC Telecommunications, Inc.
11. Use the rivets removed in step 9 to secure the replacement fan to the mounting plate and
grill. Orient the fan so the wiring harness is on the top and the arrow on the fan points
away from the enclosure. Make certain the rubber grommets are left in place on the
mounting plate.
12. Connect the wiring harness connector to the circuit board connector.
13. Secure the fan/grill assembly to the back of the housing (see Figure 5-5) using the four
pan-head screws removed in step 6. Do not overtighten the screws. The screw threads can
be easily stripped if too much torque is used to tighten the screws.
14. Re-install the STM in the outdoor cabinet or indoor mounting shelf and then re-connect all
cables in the reverse order in which they were disconnected (see Figure 5-4).
15. Place the STM On/Off switch in the ON position (press I).
16. Verify that the fan runs properly following power-up.
17. Notify the NOC or alarm monitoring system operator that the system is going back online.
5.5 Linear Power Amplifier Fan Replacement Procedure
The LPA is equipped with a front-mounted cooling fan. The fan draws cool air into the LPA
housing. Replacement of the fan requires that the STM be turned off for a short period of time
and that the LPA be removed from the outdoor cabinet or indoor mounting shelf. Use the
following procedure to remove and replace the LPA cooling fan.
1. Before working on the LPA or handling a fan, slip on an Electro-Static Discharge (ESD)
wrist strap and connect the ground wire to an earth ground source. Wear the ESD wrist
strap while completing each section of the fan installation procedure.
2. Notify the NOC or alarm monitoring system operator that the system is going offline.
3. Place the STM On/Off switch in the OFF position (press O).
4. Loosen the captive screws that secure the LPA to the RU outdoor cabinet or indoor
mounting shelf and carefully withdraw the LPA from its mounting slot.
5. Remove the four Phillips-head screws that secure the fan/front panel assembly to the front
of the LPA housing as shown in Figure 5-7. Save screws for reuse.
6. Carefully withdraw the fan/front panel assembly from the LPA housing until the wiring
harness is exposed and the connector is accessible.
7. Carefully unplug the fan wiring harness connector from the LPA wiring harness connector.
8. Remove the screws, split-washers, and nuts that secure the fan and grill to the LPA front
panel as shown in Figure 5-8.
9. Separate the fan and grill from the front panel.
Warning: Electronic components can be damaged by static electrical discharge. To prevent
ESD damage, always wear an ESD wrist strap when working on the HU, STM, or LPA and
when handling electronic components.