16
System Alignment
When all modules are aligned and assembled into a system, it is necessary to make
receiver tracking, VOR/LOC converter and squelch adjustments.
COMM receiver tracking is accomplished by selecting 118.00 MHz as the active channel,
applying a 10 uV RF input signal at 118.00 MHz, and adjusting R49 on the Computer
board for minimum reading on COMM AGC line.
NAV receiver tracking is accomplished by selecting 108.00 MHz and adjusting R33 on
the Computer board for a minimum reading on NAV AGC.
Carrier squelch is adjusted by applying an unmodulated carrier at 2.0 uV to the COMM
receiver and adjusting R29 on Computer board, to just break squelch.
Noise inhibit is adjusted by applying a carrier with 30% modulation at 6.666 KHz to the
COMM receiver and adjusting R31 on the Computer board so that a 10 uV signal will
just break squelch.
Demod output level is set by R71 (Demod Level).
The 1020 Hz Filter is adjusted by monitoring the audio output and applying a 1020 Hz
modulation to the NAV Receiver input. With ‘Voice’ selected, adjust R12 (1020 Hz) for
minimum tone output.
VI. Mechanical Disassembly
The first step in mechanical disassembly is to remove the top cover by removing the nine
screws around the sides and rear of the cover. The cover may then be pried up at either
rear corner lifted slightly and slid away from the front panel.
The computer board is removed by first disengaging the connectors and then removing
the six spacers holding the computer board. The board may then be lifted from the unit.
The front panel may be disengaged by removing four screws from the sides and bottom,
and disconnecting the connectors.
The rear panel is removed by removing two screws on the bottom of the unit and one
screw from each side of the unit, and disconnecting the connectors. The transmitter
power lead can be removed by loosening the attaching screw.
The RF modules may be removed by removing the mounting screws from the bottom of
the unit and disconnecting the connectors.
To Next Page
Loading...
