Yaesu FT-757GX II, Техническое дополнение

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ALIGNMENT
LOCAL Unit
A. Third LO BPF
Remove P17 and connect a 50-ohm load across 3rd
LO OUT jack J 2008, along with the RF voltmeter.
Set the transceiver to a CW mode, and while
receiving, adjust T 2001 and T 2002 for maximum
deflection on the voltmeter (50 m Vrms nominal).
B. SSB,
AM,
CW RX LO Level
Connect the RF voltmeter to pin 2 of 02012 and
adjust TC20
�
2 so that the difference in level be­
tween CW transmit and receive is less than 5 m Vrms
at this point (output level approximately 100
mVrms).
C. 45 MHz Bandpass Filter
With the transceiver set to the 14 MHz band,
connect the RF voltmeter to TP2006 and adjust
T 2009 and T 2010 for maximum voltmeter deflec­
tion (more than 80 m Vrms).
D. 60 MHz Bandpass Filter
Set the transceiver to the 21 MHz band, and with
the RF voltmeter connected as in the previous step,
adjust T 2011 and T 2012 for maximum deflection
(more than 80 mVrms).
E. 45 MHz Tripler
Return the transceiver to the 14 MHz band, and
connect the RF voltmeter to TP2002. Adjust T 2006
and T 2007 for maximum deflection (more than
80 mVrms).
F. 15 MHz Reference Frequency
Connect the frequency counter to TP2002 and
adjust TC2006 for 45 MHz ±20 Hz.
G. 2nd Local Oscillator Frequency
l. Connect the frequency counter to TP2007,
and tune the transceiver so that the display
indicates 14.000.00. Adjust VR2006 so that
the counter shows 32.06000 MHz ± 20 Hz.
2. Retune the transceiver so that the display
shows 13.999.99, and adjust VR2014, if
necessary, to obtain 32.05901 MHz on the
counter.
Now retune the transceiver to
14.000.00 and check that the difference in
the frequencies shown on the counter are
within 990 Hz ±5 Hz.
H. Carrier Point
Connect the frequency counter to J 2008 and
adjust the component indicated in the correspond­
ing mode for the frequency shown below:
MODE ADJUST
LSB
cw
USB
TC2oos
TC2004
VR2oos
I. BFO Frequency
COUNTER FREOUENCY
8213.400 kHz (±50 Hz)
8 21 5. 900 kHz ( ± 1 0 Hz)
8216.600 kHz (±50 Hz)
Set the transceiver to a CW mode, and connect the
frequency counter to pin 2 of 02012. Adjust
TC2001 while receiving for 15.000700 MHz (±1
O
Hz) on the counter.
J.
FM
/
AM Carrier Frequency
1. Set the transceiver to the FM mode, and
connect the frequency counter to J 2007.
Adjust VR2004 while transmitting for
8.215000 MHz (±50 Hz) on the counter.
2. Rotate the AM CAR control (VR2008) fully
clockwise, and set the transceiver to the AM
mode. Close the PTT line and check the
counter for 8.215000 MHz ±300 Hz.
K. Carrier Level
Set the transceiver to the LSB mode, and connect
the RF voltmeter to TP2001. Close the PTT line
and adjust TC2003 for 90 mVrms (±5 mV).
L. Carrier Balance
With the transceiver set to LSB, connect the RF
voltmeter to J 2007 and adjust VR2001 for
minimum voltage on the meter.
M. AM Carrier Level
1. With the RF voltmeter connected to J 2007,
set the mode to CW, key the transmitter, and
note the voltage indicated on the meter
(approx. 200 m Vrms).
2. Return to receive, switch the mode to AM,
close the PTT line and adjust AM CAR
control VR2008 for exactly half of the voltage
noted in the previous step.
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