User's Manual Part 3

CCP Backplane Troubleshooting – continued

Apr 2001

6-17

SC4812ET BTS Optimization/ATP — CDMA LMF

DRAFT

DC Power Problems

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. 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 breaker trips again, there is probably a cable or breaker

problem within the frame.

– If breaker does not trip, there is probably a defective

module or sub–assembly within the shelf.

2 Verify that the C–CCP shelf breaker on the BTS frame

breaker panel is functional.

3 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.

4 If everything appears to be correct, visually inspect the power

supply module connectors.

5 Replace the power supply module with a known good

module.

6 If steps 1 through 4 fail to indicate a problem, the C–CCP

backplane failure (possibly an open trace) has occurred.