User's Manual

Troubleshooting: SCCP Backplane

68P09255A69-3

Aug 2002

1X SC4812ET Lite BTS Optimization/ATP Software Release 2.16.1.x

PRELIMINARY

6-24

DC Power Problems

WARNING

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.

No DC Input Voltage to SCCP Shelf Power Supply

Modules

Table 6-26: No DC Input Voltage to Power Supply Module

Step Action

1 Verify DC power is applied to the frame. Determine if any circuit breakers are tripped.

NOTE

If a breaker has tripped, remove all modules from the SCCP shelf and attempt to reset it.

- If breaker trips again, there is probably a cable or breaker problem within the frame or DC PDA.

- If breaker does not trip, there is probably a defective module or sub-assembly within the shelf.

Perform the tests in Table 2-3 to attempt to isolate the module.

2 Verify that the PS1 and PS2 circuit breakers on the DC PDA are functional.

3 Remove the frame rear access panel (Figure 2-1), and use a voltmeter to determine if the input voltage

is being routed to the SCCP backplane. Measure the DC voltage level between:

 The PWR_IN_A and PWR_RTN_A contacts on the extreme right side at the rear of the backplane

 The PWR_IN_B and PWR_RTN_B contacts on the extreme right side at the rear of the backplane

- If the voltage is not present, there is probably a cable or circuit breaker problem within the frame

or DC PDA.

4 If everything appears to be correct, visually inspect the PS1 and PS2 power supply module connectors.

5 Replace the power supply modules with known good modules.

6 If steps 1 through 4 fail to indicate a problem, an SCCP backplane failure has occurred (possibly an

open trace).