User's Manual Part 3

C–CCP Backplane Troubleshooting – continued
DRAFT
SCt4812T CDMA BTS Optimization/ATP
Mar 2001
6-18
DC Power Problems
Perform the procedure in Table 6-22 to troubleshoot a DC input voltage
to power supply module failure.
Potentially lethal voltage and current levels are routed to
the BTS equipment. This test must be carried out with a
second person present, acting in a safety role. Remove all
rings, jewelry, and wrist watches prior to beginning this
test.
WARNING
No DC Input Voltage to Power Supply Module
Table 6-22: No DC Input Voltage to Power Supply Module
Step Action
1 Verify DC power is applied to the BTS frame.
2 Verify there are no breakers tripped.
* IMPORTANT
If a breaker has tripped, remove all modules from the applicable shelf supplied by the breaker and
attempt to reset it.
– If the breaker trips again, there is probably a cable or breaker problem within the frame.
– If the breaker does not trip, there is probably a defective module or sub–assembly within the shelf.
3 Verify that the C–CCP shelf breaker on the BTS frame breaker panel is functional.
4 Use a voltmeter to determine if the input voltage is being routed to the C–CCP backplane by
measuring the DC voltage level on the PWR_IN cable.
– If the voltage is not present, there is probably a cable or breaker problem within the frame.
– If the voltage is present at the connector, reconnect and measure the level at the “VCC” power
feed clip on the distribution backplane.
– If the voltage is correct at the power clip, inspect the clip for damage.
5 If everything appears to be correct, visually inspect the power supply module connectors.
6 Replace the power supply module with a known good module.
7 If steps 1 through 5 fail to indicate a problem, a C–CCP backplane failure (possibly an open trace) has
occurred.
6