Receiver Adjustments - Icom IC-7400 Service Manual

5-4 RECEIVER ADJUSTMENTS

ADJUSTMENT ADJUSTMENT CONDITION
RX PEAK 1 • Displayed freq. : 14.100000 MHz
• Mode
• Set following selections, controls
and functions as:
[RF/SQL]
[PITCH]
[AGC] : OFF , [ATT] : OFF
[NB] : OFF , [RIT] : OFF
PBT1 : Center, PBT2 : Center
[P.AMP]
IF Filter
[NR] switch
[NOTCH] switch: OFF
• Preset L215 (RF unit) to 2 rotation
downside from top of the coil's case.
• Connect an SSG to [ANT1] con-
nector and set as:
Frequency
Level
Modulation
• Receiving
• Filter
• Set an SSG as :
Frequency
Level
Modulation
• Receiving
3 • Displayed freq. : 0.03000 MHz
• Set an SSG as :
Level
• Receiving
RECEIVER 1 • Displayed freq. : 14.100000 MHz
TOTAL GAIN • Mode
• Filter
• [P.AMP]
• Set an SSG as :
Frequency
Level
Modulation
• Receiving
1
NOISE • Displayed freq. : 14.100000 MHz
BLANKER • Mode
• [P.AMP]
• [NB]
• [NB LEVEL]
• Set an SSG as :
Frequency
Level
Modulation
and apply following signal to [ANT1]
connector.
100 msec.
• Preset R200 (MAIN unit) to the 12
o'clock position.
• Receiving
2 • [NB]
• Receiving
*This output level of a standard signal generator (SSG) is indicated as SSG's open circuit.
U N T I
Rear
: USB panel
: Center
: Center
: P.AMP1
: 2.4 kHz
: OFF
: 14.101500 MHz
: 10 µV* (–87 dBm)
: 1 kHz/±3.5 kHz dev.
: 15 kHz
: 14.100000 MHz
: 1 mV* (–47 dBm)
: 1 kHz/±5.0 kHz Dev.
: OFF
MAIN
: USB
: 2.4 kHz
: OFF
: 14.101500 MHz
: 160 mV* (–3 dBm)
: 1 kHz/±5.0 kHz dev.
MAIN
: USB
: P.AMP1
: OFF
: 50%
: 14.101500 MHz
: 18 µV* (–82 dBm)
: OFF
1 msec.
: ON
MEASUREMENT
L O C A I T O N
Connect an AC milli- Maximum audio output
volt meter to [EXT level
SP] connector with
an 8 Ω load.
Connect an AC milli- Minimum noise output
volt meter to [EXT level
SP] connector with
an 8 Ω load.
Connect an oscillo-
scope to the check
point CP1460.
Connect an oscillo- Maximum noise level
scope to the check
point CP200.
At the point where the
voltage just reduces.
5 - 8
ADJUSTMENT
POINT
VALUE
U N T I A
RF
4.0 Vp-p MAIN
MAIN
D J U S T
L242,
L241 ,
R218
R1469
L201,
L202,
L203,
R200