User's Manual

Manual 7-9410-1.2 Page 19

TX RX Systems Inc. 10/21/05

61-83B-50-XXX-XX UserMan page 19 of 25

lightning strikes, failures may occur. The following

procedures may be followed for detecting a mal-

functioning unit or as part of a periodic mainte-

nance program.

1) The heatsink area should be cleared of dust

and debris.

2) Inspect the unit to see that the two power sup-

ply LED DC indicators are lit (remove any dust

or debris that may obscure the LEDs). This will

verify that DC power is flowing properly. Check

all hardware for tightness.

3) Compare system performance to initial perfor-

mance levels measured when the system was

first installed. The lack of signal can be traced

to a malfunctioning amplifier by progressive sig-

nal monitoring from the output (far end) to the

input end of the system noting the area where

the signal returns to normal level. The next

amplifier toward the output end of the system

will probably be the one that failed.

Measure the gain at any convenient frequency

in the working frequency band to verify that the

performance is still within specifications.

Power Amplifier Replacement

The SB II power amplifiers are field replaceable.

Follow the steps listed below in sequential order.

The required tools are a #1 Phillips screwdriver

and a 5/16” open-ended wrench.

Note: Power to the SB II cabinet must

be turned OFF during the power

amplifier replacement process.

1) Remove the Phillips screws which hold the

amplifier into place, refer to Figure 11. The nuts

holding the screws are pressed into the cabinet

NOTE

Figure 11: Remove 14 mounting screws to detach amplifier assembly from cabinet.

Remove Screws

Remove

Screws

Remove

Screws