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HARRIS
888-9058-001
WARNING: Disconnect and lockout AC primary power prior to servicing
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3.18.3 Power RAISE/LOWER
The power RAISE and LOWER buttons on the main control panel duplicate the exciter
RAISE and LOWER switches. Upon depressing one of these switches on the main
controller, the appropriate command is relayed to the exciter. In transmitters with
optional dual exciters, the RAISE/LOWER commands are routed only to the exciter
currently enabled; the standby exciter power is not changed while making adjustments to
the on-air exciter.
In dual exciter operation, after one exciters has been adjusted for correct visual and aural
power, switch to the standby exciter and adjust visual and aural power again. The second
exciter will then immediately begin running at the correct drive level when exciters are
switched at a later time.
The exciter power controls are active even if AC power is removed Thus, avoid RAISE
commands if the transmitter is not actually on. If any doubt as to the exciter level setting
exists, depress and hold the LOWER command for about 15 seconds to assure a safe low
drive condition upon turn-on.
The RAISE/LOWER controls are dual-speed controls. The rate of power level change
will be slow for the first few seconds after a button is pressed and held. The power level
will change at a faster rate if the button is held down longer. To return to the slower rate,
release the button momentarily; the control will revert to the slow speed when the button
is pressed again.
3.19 AGC Setup
The transmitter should be operating at normal ambient temperature and warmed up
approximately 30 minutes. This procedure is the same for visual and aural.
NOTE:
The twelve turn potentiometers used for EXC ADJUST and SET can be from
different manufactures. Electrically they have the same value but differ in the
direction the control is rotated to increase the voltage.
a
. Reduce exciter power to zero, and switch AGC MODE switch to OFF.
b.
Increase exciter power for 100% transmitter power output.
c.
Measure the exciter sample at the EXC test point. The value should be between
1.2 and 1.5 volts DC.
d.
Rotate the EXC ADJUST pot on top of AGC card to bring the voltage within
this range if needed.