46
G. Receiver Front End
1.
Remove the radio covers. Remove the two mount-
ing screws and unplug the control head. (For earlier
models, also remove the two mounting screws and
the control head rear housing.) Disconnect the
coax cable that passes through the front of the
chassis to the RF board.
2.
Remove the PA assembly and disconnect the coax
cable that passes through the rear of the chassis to
the receiver front end.
3.
Remove four screws, the front-end cover, and care-
fully lift the receiver front-end board from the
chassis.
NOTE
Be careful to insert the RX injection coax straight into
the receptacle on the VCO board, and be sure it is
fully inserted. Be careful not to bend the tip of the
coax, which provides the contact for the connection.
4.
Install the new assembly, being careful not to dam-
age the RF connection that passes through the
chassis to the VCO.
5.
Reconnect both coax cables, then install the front-
end cover and four mounting screws. Install the PA
assembly and control head. (For earlier models, the
control head rear housing must be installed before
the control head is attached.)
NOTE
No alignment is required.
H. VCO Assembly
1.
Remove the radio covers. Remove the PA assem-
bly and disconnect the TX injection coax that
passes through the chassis to the VCO board.
2.
Remove the RF board cover.
3.
Remove the six mounting screws and the cover.
Carefully lift up the board far enough to expose the
RX injection coax underneath, which runs from a
receptacle on the VCO, through a hole in the chas-
sis, to the receiver front-end assembly. Unplug the
coax from the receptacle on the VCO board. Lift
straight up on the VCO board to remove it from the
chassis.
4.
To install the new board, plug in the RX injection
coax (from the receiver front end) into the recepta-
cle near the outer edge of the board. Align the
opposite-edge connector with the RF board connec-
tor and snap it into place.
NOTE
Ensure that the board and gasket are straight and
that the board does not bind as the screws are tight-
ened, pulling the board down to the cavity ledge.
Tighten screws evenly to avoid warping the board. It
is very important to use proper screw torque to
ensure proper operation in vibration environments.
5.
Connect the PA board’s RF cable to the VCO board
connector (through the chassis).
6.
Install the VCO cover and six mounting screws, and
the RF board cover.
7.
Install the PA assembly and the radio covers.
8.
See Table 16 and perform the alignment proce-
dures indicated.
I. RF Board
1.
See the previous paragraph and remove the VCO
board. Remove the control head. (For earlier mod-
els, also remove the control head rear housing.)
Disconnect the RF cable that passes through the
chassis to the RF board.
2.
Remove six mounting screws and remove the RF
board.
3.
Install the new board and connect the RF cable
through the front of the chassis to the RF board.
Install the six mounting screws, but wait to tighten
them until after you install the VCO board.
NOTE
Make sure the male-to-male command board header
is fully seated in the command board before installing
the RF board.
4.
Install the VCO board, and tighten the RF and VCO
board mounting screws. It is very important to use
proper screw torque on both boards to ensure prop-
er operation in vibration environments.
5.
Install the control head and radio covers. (For earli-
er models, the control head rear housing must be
installed before the control head is attached.)
6.
See Table 16 and perform the alignment proce-
dures indicated.
VIII. SPECIAL REPAIR PROCEDURE
A. Minimum RF Performance Tests for Board
Replacement (See Table 15).
B. Alignment via IBM PC
Table 16 details the procedures required and the
sequence in which the procedures must be performed
after each specific board replacement. These alignment
procedures are detailed in the alignment section of this
manual. Follow the details carefully and in the exact
sequence specified. Failure to comply may result in
improper radio operation.
C. Power
Amplifiers
Apply a thin coat of thermal compound (for exam-
ple, Motorola part no. 11-83166A01) to the power
module and voltage control pass device and final device
(in 30-watt models) heatsink mounting surfaces.
Содержание Spectra
Страница 6: ...v PERFORMANCE SPECIFICATIONS FOR SPECTRA PRIVACY PLUS TRUNKED CONVENTIONAL 900 MHz RADIO ...
Страница 7: ...vi PERFORMANCE SPECIFICATIONS FOR SPECTRA SMARTNET TRUNKED CONVENTIONAL 900 MHz RADIO ...
Страница 8: ...vii PERFORMANCE SPECIFICATIONS FOR SPECTRA 9000 RADIOS 900 MHz 30 WATTS ...
Страница 25: ...1 GENERAL INFORMATION 1 ...
Страница 73: ...53 INSERT GPW 7221 B Figure 22 Front Panel Diagnostics Key Closure Displays ...
Страница 75: ...INSERT GXW 4278 O PICKUP FROM PW 4320 O 55 CONTROL STATION WIRING DIAGRAM ...
Страница 79: ...PUSHBUTTON SPECTRA 900 MHz RADIO MECHANICAL EXPLODED VIEW 59 INSERT GXW 6225 B ...
Страница 96: ...82 MECHANICAL EXPLODED VIEW PARTS LIST FOR SPECTRA 900 MHz RADIO ...