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220 V AC P ower Supply Module (PSM) Shelf Chapter 10: PSM Shelf R eplacement Procedures
Before you begin
Before you begin, record the pertinent information in T able 10 -4 .
Table 10 -4 Item number replacement list
Item
Number
BTS number
F ailed 220 V AC PSM shelf
number
220 V AC PSM shelf replacement procedure
This procedure requires working on or around circuitry which is extremely sensitiv e
to ESD . W ear a conductiv e, high impedance wrist str ap during the procedure. Use
appropriate safet y measures.
T o replace the 220 V AC PSM shelf perform Procedure 10 -3 and then Procedure 10 -4 .
Procedure 10 -3 R emo ving the failed 220 V AC PSM shelf
A T THE OMCR
1
Shut down site signaling functions according to Procedure 3-2 Shutdown site signaling
functions procedure for a packet BTS on page 3- 5 .
A T THE BTS SITE
2
P ower down the 220 V AC UBS Macro BTS frame according to the section: P owering Down
the Frame on page 2- 3 .
Mak e sure the facilit y circuit break er controlling external 220 V AC power to the
220 V AC PSM shelf is set to the OFF position.
3
Using a T25 TORX bit and driver , loosen the captive retaining thumbscrews on all of the PSM
modules until the thumbscrews are disengaged from the shelf .
Continued
10 -12 68P09283A64 -3
FOA SEP 2007