ADC Broadband System 67

ADCP-61-471 • Issue 4 • June 2000 • Section 2: Operation and Maintenance

DLP-508

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–48 VDC POWER SUPPLY TEST

Summary: This procedure provides instructions for testing the voltage at the power terminal block located on the Soneplex Broadband chassis backplane. The multimeter should indicate between –42.5 VDC and –56.5 VDC.

1.Obtain a multimeter capable of measuring 40 to 60 volts DC.

2.Are fuses installed at the fuse and alarm panel?

•If No, continue to Step 3.

•If Yes, continue to Step 4.

3.Install –48 VDC fuses in both A and B fuse holders.

4.Are any of the fuses open or blown?

•If No, continue to Step 8.

•If Yes, continue to Step 5.

5.Replace blown fuse or fuses.

6.Did fuse blow again?

•If Yes, continue to Step 7.

•If No, continue to Step 8.

7.Clear trouble in the fuse and alarm panel or chassis backplane.

8.Using a multimeter, measure and record the DC voltages. Measure voltage by placing one probe on the positive contact and the other probe on a solid frame ground. Observe DC polarity when taking voltage measurements.

•Measure the A power feed bus voltage at the fuse holder.

•Measure the B power feed bus voltage at the fuse holder.

•Measure the voltage across the –48 A and RTN A terminals on the chassis backplane.

•Measure the voltage across the –48 B and RTN B terminals on the chassis backplane.

9.Was the voltage measured at all points between –42.5 VDC and –56.5 VDC?

•If Yes, Stop! You have completed this procedure.

•If No, continue to Step 10.

10.The problem is in the fuse and alarm panel, the power feed cabling, or at the chassis. Inspect and repair as necessary.

Stop! You have completed this procedure.

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