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Pre–Power–up Tests
DC Power Pre-test (BTS Frame)
2
Step
1
Physically verify that all DC power sources supplying power to the frame are OFF or disabled.
2
On each frame:
Unseat all circuit boards (except CCD and CIO cards) in the C–CCP shelf and LPA shelves, but
S
leave them in their associated slots.
Set C–CCP shelf breakers to the OFF position by pulling out power distribution breakers (labeled
S
C–CCP 1, 2, 3) located on the power distribution panel.
Set LPA breakers to the OFF position by pulling out the LPA breakers (8 breakers, labeled 1A–1B
S
through 4C–4D) located on the power distribution panel.
Continue with Step 3 for –48 V or Step 4 for +27 V.
For –48 V configurations ONLY:
3
Verify the resistance on the –48 V bus:
– Remove the Power Supply Modules (PSMs).
– Verify that the resistance from the power (–) feed terminal with respect to the ground terminal on
the top of the frame measures > 500 Ω (see Figure 2-3).
Verify the resistance on the +27 V bus:
– Remove PSM#1 or the filler panel.
! CAUTION
Do not put probes inside Elcon connectors.
– Place the Digital Multimeter probes on the mounting screws on the Elcon connector (bottom two
Elcon connectors).
– If reading is < 500
breaker. Isolate the problem before proceeding. A reading > 3 M
missing) bleeder resistor (installed across the filter capacitors behind the breaker panel).
For +27 V configurations ONLY:
4
Verify that the resistance from the power (+ or –) feed terminals with respect to the ground terminal on
the top of the frame measures > 500 Ω (see Figure 2-3).
– If reading is < 500
breaker. Isolate the problem before proceeding. A reading > 3 M
missing) bleeder resistor (installed across the filter capacitors behind the breaker panel).
5
Set the C–CCP breakers to the ON position by pushing them IN one at a time. Repeat Step 3 (for
–48 V) or Step 4 (for +27 V) after turning on each breaker.
NOTE
If the multimeter stays at 0 Ω after inserting any board/module, a short probably exists in that
board/module. Replace the suspect board/module and repeat the test. If test still fails, isolate the
problem before proceeding.
2-6
Before applying any power to the BTS frame, follow the procedure in
Table 2-2 while referring to Figure 2-3 to verify there are no shorts in the
BTS frame DC distribution system.
Table 2-2: DC Power Pre–test (BTS Frame)
a short may exist somewhere in the DC distribution path supplied by the
Ω,
a short may exist somewhere in the DC distribution path supplied by the
Ω,
1X SC 4812T-MC Multicarrier BTS Optimization/ATP
Action
could indicate an open (or
Ω
could indicate an open (or
Ω
68P64115A21–B
. . . continued on next page
Sept 2003
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