User's Manual Part 2

Initial Power Up continued
Apr 2001
2-7
SC4812ET BTS Optimization/ATP CDMA LMF
DRAFT
DC Power Pre-test (BTS Frame)
Before applying any power to the BTS cabinet, verify there are no shorts
in the RF or power DC distribution system (see Figure 2-5).
Table 2-6: DC Power Pretest (BTS Frame)
Step Action
1 Physically verify that all AC rectifiers supplying power to the RF cabinets are OFF or disabled (see
Figure 2-5). There should be no 27 Vdc on DC feed terminals.
2 On each RF cabinet:
Unseat all circuit boards/ modules in the distribution shelf, transceiver shelf, and Single Carrier
Linear Power Amplifier (SCLPA) shelves, but leave them in their associated slots.
Unseat all circuit boards (except CCD and CIO cards) in the CCCP shelf and LPA shelves, but
leave them in their associated slots.
Set CCCP shelf breakers to the OFF position by pulling out power distribution breakers (labeled
CCCP 1, 2, 3 located on the power distribution panel).
Set LPA breakers to the OFF position by pulling out power distribution breakers (8 breakers,
labeled 1A1B through 4C4D located on the power distribution panel).
3 Verify that the resistance from the power (+) feed terminals with respect to the ground terminal on the
cabinet measures >
500 (see Figure 2-5).
If reading is < 500 Ω, a short may exist somewhere in the DC distribution path supplied by the
breaker. Isolate the problem before proceeding. A reading > 3 M
could indicate an open (or
missing) bleeder resistor (installed across the filter capacitors behind the breaker panel).
4
Set the 400 Amp Main Breaker and the CCCP breakers (CCCP 1, 2, 3) to the ON position by
pushing them IN one at a time. Repeat step 3 after turning on each breaker.
* IMPORTANT
If, after inserting any board/module, the ohmmeter stays at 0 Ω, 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.
5
Insert and lock the DC/DC converter modules into their associated slots one at a time. Repeat step3
after inserting each module.
A typical response is that the ohmmeter will steadily climb in resistance as capacitors charge, finally
indicating approximately 500
.
! CAUTION
Verify the correct power/converter modules by observing the locking/retracting tabs appear as follows:
(in +27 volt systems)
6 Insert and lock all remaining circuit boards and modules into their associated slots in the CCCP shelf.
Repeat step 3 after inserting and locking each board or module.
A typical response is that the ohmmeter will steadily climb in resistance as capacitors charge,
stopping at approximately 500
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