Receiver Adjustments - Icom IC-756PRO III Service Manual

4-4 RECEIVER ADJUSTMENTS

ADJUSTMENT ADJUSTMENT CONDITION
RX PEAK 1 • Display freq.
• [DUALWATCH] : OFF
• Mode
• Set following selections, controls
and functions as:
[AGC] : MID
[NB] : OFF
PBT1 : Center
Filter
[P.AMP]
[RF/SQL]
[NOTCH]
[NR] switch : OFF
• Preset center dots to 90˚ differ-
ence on the roter and stater of
C1036 and C1211.
• Connect an SSG to [ANT1] con-
nector and set as:
Frequency
Level
Modulation
• Receiving
Adjust L211 to upper side of 2 peak points.
2 • Sub display freq. : 14.100000 MHz
• [DUALWATCH]
• Mode
• [BAL]
• Set an SSG as:
Level
• Receiving
Adjust L1011 to upper side of 2 peak points.
FM 1 • Display freq.
DISTOR- • [DUALWATCH]
TION • Mode
• Filter
• [P.AMP]
• Connect an SSG to [ANT1] con-
nector and set as:
Frequency
Level
Modulation : 1 kHz/±5.0 kHz Dev.
• Receiving
Adjust in sequence L1751, L1702, L1751.
MIXER 1 • Display freq.
BALANCE • Sub display freq. : 1.900000 MHz
• [DUALWATCH]
• Mode
• [BAL]
• Apply no RF signal to [ANT1] con-
nector.
• Receiving
2 • [BAL]
• Receiving
*This output level of standard signal generator (SSG) is indicated as SSG's open circuit.
MEASUREMENT
UNIT
: 14.100000 MHz Rear
panel
: USB
[ATT] : OFF
[RIT] : OFF
PBT2 : Center
: 2.4 kHz
: P.AMP1
: Center
: OFF
: 14.101500 MHz
: 10 µV* (–87 dBm)
: 1 kHz/±5.0 kHz dev.
Rear
: ON panel
: USB
: Max. CW
: 10 µV* (–87 dBm)
: 14.100000 MHz Rear
: OFF panel
: FM
: 15 kHz
: P.AMP1
: 14.100000 MHz
: 500 µV* (–53 dBm)
: 1.900000 MHz Rear
panel
: ON
: USB
: Max. CCW
: Max. CW
LOCATION
C o n n e c t a n A C Minimum audio output
millivoltmeter to [EXT level
SP] connector with an
8 Ω load.
C o n n e c t a n A C Minimum audio output
millivoltmeter to [EXT level
SP] connector with an
8 Ω load.
Connect a distor tion Minimum distortion level
m e t e r t o [ E X T S P ]
connector with an 8 Ω
load.
Connect a spectrum Minimum noise output
analyzer to the check level.
point J1651.
4 - 8
ADJUSTMENT
POINT
VALUE
UNIT
RF-B L1211,
L1751,
L1752,
C1238
RF-B L1011,
C1036
RF-B L1751,
RF-B R1206,
R1207
R1006,
R1007
AD-
JUST
L1702