User's Manual Part 2

High and Medium Stability Oscillator Module – continued
9-8 1X SC480 BTS Hardware Installation, Optimization/ATP, and FRU MAY 2004
PRELIMINARY
Replacement Procedure
This procedure requires working around circuitry that is
extremely sensitive to Electrostatic Discharge (ESD). Wear
a conductive, high impedance wrist strap during the
procedure.
Use appropriate safety measures.
CAUTION
If desired, record the BTS and HSO/MSO serial number of the failed
unit in Table 9-54 at the end of this chapter.
Remove HSO or MSO Module
Follow the procedure in Table 9-3 to remove the HSO or MSO module.
See Figure 9-4.
Table 9-3: Procedure to Remove HSO or MSO Module
Step Action
1 Notify operator that the HSO or MSO replacement procedure is starting and that alarms can be
expected.
2 Put on an ESD wrist strap or other approved grounding device.
3 If not already done, remove BTS front panel cover by grasping finger grooves at the top and bottom
and pulling simultaneously.
4 If not already done, remove HSO Module cover panel by turning latch, gently pulling it open, and
sliding it out towards the right. The panel has a flange that fits into a slot in the frame.
5 Use a T20 star bit to remove two M4 screws securing HSO or MSO to frame.
6 Pull on handle to gently slide HSO or MSO out and disconnect cable from side. See Figure 9-5.
Install HSO or MSO
Follow the procedure in Table 9-4 to install the HSO or MSO module.
Table 9-4: Procedure to Install HSO or MSO Module
Step Action
1 Put on an ESD wrist strap or other approved grounding device.
* IMPORTANT
The HSO and MSO will only fit into the top slot. DO NOT force it into the lower slot.
2 Connect cable to side of HSO or MSO and slide into top slot.
3 Secure HSO or MSO to frame using two M4 screws. Torque screws to 2.3 N–M (20 in–lbs).
table continued on next page
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