User's Manual

68P81093C75-A 9-33
Physical Replacement of
the Power Amplifier
1. Turn off the station’s power by unplugging the AC and DC
power cords from the top panel.
2. Remove the eight Phillips screws from the edges of the station’s
top panel and lift the chassis out of the case.
3. Remove the backplane as described in the Backplane
replacement subsection, but disengage only the PA ribbon cable
connector (P10) and the red and black power leads (two tab
connectors closest to the bottom edge of the backplane). All
other cables can remain connected.
4. Remove the four Phillips screws from the front, right quadrant
of the top panel to release the PA. When removing the fourth
screw, support the PA inside the chassis to prevent it from
falling.
5. Disconnect all four cables between the PA and the station:
a. Unplug the red and black power cable from the PA.
b. Unscrew the mini-UHF connector from the PA.
c. To remove the PA ribbon cable connector, remove the two
Torx screws holding the metal clip over the connector. Pull
the connector loose from the PA.
d. For VHF and UHF stations, unscrew the mini-UHF
connector on the remaining cable from the front of the
Exciter. For 800 MHz stations, unplug the SMB connector
on the cable going to the left end of the IPA module. To
access the connector, it may be necessary to partially slide
out the Exciter mounting plate as described in the
Intermediate PA replacement subsection.
6. Reconnect all four cables removed in Step 4. The ribbon cable
connector is keyed so it cannot be attached incorrectly.
Remember to reattach the metal clip over the ribbon cable
connector.
7. Take the sheet of black thermal conductive film that was
between the old PA and the chassis and place it on the new PA.
8. Place the PA in the chassis and line up the screw holes in the PA
and the thermal film with the holes in the top panel of the
chassis. (It may be useful to insert a pencil, pen, or small
screwdriver through the screw holes in the top panel to aid in
aligning the holes in the conductive film with those in the PA.)
9. While holding the PA with one hand, start two or more Phillips
screws in the top panel to hold the PA in place. Insert the
remaining screws and tighten all four.