Icom Ic706Mk2g Hf/Vhf/Uhf All Mode Tranciever Service Manual

							3 - 6 The “FOR”, “VFOR” and “UFOR” voltages are combined to
the “FORL” voltage and then applied to IC1091b (pin 6). The
“POCV” voltage from the D/A converter (IC2201, pin 3),
determined by the RF power setting, is applied to IC1091b
(pin 5) as the reference voltage.
When the “FORL” voltage exceeds the “POCV” voltage, ALC
bias voltage from IC1091a (pin 1) controls the PIN diodes
(D521, D522, D572, D573) using Q1092. This adjusts the
output power to the level determined by the RF power set-
ting until the “FORL” and “POCV” voltages are equalized.
In AM mode, IC1091a operates as an averaging ALC ampli-
fier with Q1091 and C1091. Q1071 turns ON and the
“POCV” voltage is shifted for 40 W AM output power (maxi-
mum, 20 W for 144 MHz band, 8 W for 440 MHz band)
through R1080.
The ALC bias voltage from IC1091a is also applied to the
main CPU (IC2001 pin 34) as the “ALCL” voltage for ALC
meter indication.
An external ALC input (minus voltage) from the [ACC] sock-
et (pin 6) is shifted to plus voltage at D1131 and is applied
to the buffer amplifier (Q1131). External ALC operation is
identical to that of the internal ALC.
3-2-8 APC CIRCUIT (MAIN BOARD)
The APC (Automatic Power Control) circuit protects the
power amplifiers on the PA unit from high SWR and exces-
sive current for the HF/50 MHz band.
The reflected wave signal appears and increases on the
antenna connector when the antenna is mismatched. The
HF/50 MHz reflected signal level is detected at D10 (FILTER
board), and is amplified at the APC amplifier (IC1091c) and
applied to the ALC circuit as the reference voltage.
For the current APC, the driving current at the power ampli-
fier is detected in the voltages (“ICH” and “ICL”) which
appear at both terminals of a 0.012 ½resistor (R201) on the
PA unit. The detected voltages are applied to the differential
amplifier (IC1091d, pins 13, 12). When the current of the
power amplifier exceeds 22 A, IC1091d controls the ALC
line via IC1091a to prevent excessive current flow.
3-2-9 RF, ALC, SWR METER CIRCUITS
(MAIN BOARD)
While transmitting, RF, ALC or SWR meter readings are
available and can be selected with the [MET] switch.
(1) Power meter
The “FOR”, “VFOR” and “UFOR” voltages are combined to
the “FORL” voltage, and it is then applied to the main CPU
(IC2001, pin 35) via the analog switch (IC2101, pins 11, 13)
for indicating the output power.
(2) ALC meter
The ALC bias voltage from IC1091a pin 1 is applied to the
main CPU (IC2001, pin 34) via the “ALCV” signal line for
indicating the ALC level.
(3) SWR meter
The “FORL” and “REFL” voltages are applied to the main
CPU (IC2001, pins 32 and 36) via the analog switch
(IC2101, pins 11, 13 and 4, 3) respectively. The main CPU
compares the ratio of “FORV” to “REFV” voltage and indi-
cates the SWR for the [ANT1] connector.
3-3 PLL CIRCUITS
3-3-1 GENERAL
The PLL unit generates a 1st LO frequency
(69.0415–530.0115 MHz), a 2nd LO frequency (60 MHz), a
BFO frequency (9.01 MHz), an FM 3rd LO frequency
(9.4665/9.4650 MHz) and a TX FM PLL reference frequen-
cy (9.0115/9.0100 MHz).
The 1st LO PLL adopts a mixer-less dual loop PLL system
and has 3 VCO circuits. The BFO uses a DDS and the 2nd
LO uses a fixed frequency double that of the crystal oscilla-
tor.
3-3-2 1ST LO PLL CIRCUIT
The 1st LO PLL contains a main loop and reference loop
forming a dual loop system.
The reference loop generates a 10.6605 to 10.683 MHz fre-
quency using a DDS circuit, and the main loop generates a
69.0415 to 269.50575 MHz frequency using the reference
loop frequency.
While operating on 60 MHz and above, the output is doubled
at D531 for oscillating a wide frequency range.
(1) REFERENCE LOOP PLL
The oscillated signal at the reference VCO (Q1, D1) is
amplified at the amplifiers (Q21, Q51) and is then applied to
the DDS IC (IC101, pin 46). The signal is then divided and
detected on phase with the DDS generated frequency.
The detected signals output from IC101 (pin 56) is convert-
ed into a DC voltage (lock voltage) at the loop filter (R133,
R134, C133) and then fed back to the varactor diode (D1) in
the VCO circuit.
(2) MAIN LOOP PLL
The oscillated signal at one of the main loop VCOs (Q301,
Q331, Q361) is amplified at the buffer amplifiers (Q10) and
is then applied to the PLL IC (IC461, pin 6). The signal is
then divided and detected on phase with the reference loop
output frequency.
The detected signal output from the PLL IC (IC461, pin 2) is
converted into a DC voltage (lock voltage) at the active loop
filter and then fed back to one of the varactor diodes (D301,
D331, D361) in the VCO circuits. While operating on 60 MHz
and above, the VCO output is doubled at the doubler circuit
(D531) and amplified at the ampolifier (IC541).
The oscillated signal passes through a low-pass or band-
pass filter and is then applied to the MAIN board as a 1st LO
signal. 
						

							3 - 7
3-3-3 2ND LO AND REFERENCE OSCILLATOR
CIRCUITS
The reference oscillator (X621, Q621) generates a 30.0
MHz frequency used for the 1st LO and BFO circuits as a
system clock and for the 2nd LO signal.
The oscillated signal is amplified at the buffer amplifier
(Q661), and is doubled at Q681 and the 60 MHz frequency
is picked up at the bandpass filter (L681, L682). The 60 MHz
signal is applied to the MAIN board as a 2nd LO signal.
3-3-4 BFO CIRCUIT
The DDS IC (IC901) generates a 10-bit digital signal. The
signal is converted into an analog wave signal at the D/A
converter (R951–R970). The analog wave is passed
through the high-pass filter and low-pass filter. The 9 MHz
BFO signal is then applied to the MAIN board via the “BFO”
signal line.
While transmitting in RTTY mode, the RTTY keying signal is
applied to IC901 pin 3 to shift the generated frequency and
to obtain 2 frequencies for FSK operation.
While receiving in FM or FM narrow mode, the BFO circuit
generates a 9.4665 MHz frequency as the 3rd LO signal.
While transmitting in FM or FM narrow mode, the BFO cir-
cuit generates a 9.0115 MHz or 9.0100 MHz frequency as
the TX FM PLL reference frequency, respectively.
69.0415–
539.0115 MHz
(1st LO)
10.665–
10.683 MHz129.0115–
539.0115 MHz
69.0415–
129.0115 MHz
60.0 MHz
(2nd LO)
[ANT1][ANT2]
1st mixer
D271 0.03–
60 MHz60–
470 MHz
9.01 MHz
(BFO)
9.4665 MHz (FM)
9.4650 MHz (FM nar.) 9.0115 MHz (FM)
9.0100 MHz (FM nar.)
to FM IF IC
(IC791) to TX FM
PLL IC
(IC1011)
IC901 IC101 IC461
Q681
PLL UNIT MAIN BOARD
Q301
Q331
Q361
Q1
Phase
detector
1⁄N divider
1⁄86
Phase
detector
Main loop PLL
Ref. loop PLL
DDS
2
2
DDS
D/A
BPF
BPF
2nd mixer
D551Product
detector
IC841 69.0115 MHz
(WFM: 70.7 MHz)
to AF selector switch
Ref. Osc.
30.0 MHz
X621
BPF
1st IF 2nd IFAF signals
Q621to WFM detector
(IC631)
• FREQUENCY CONSTRUCTION 
						

							• BFO frequency
IF shift: Center, RTTY: Normal polarity
3-4 LOGIC CIRCUITS
3-4-1 BAND SELECTION DATA
(MAIN BOARD AND PLL UNIT)
To select the correct RF low-pass filter, high-pass filter and
VCOs on the PLL unit, the CPU outputs the following band
selection data from the I/O expander (MAIN board; IC2231,
IC2232), the D/A converter (MAIN board; IC2201) or DDS IC
(PLL unit; IC101) depending on the display frequency.
The D/A convertor output from IC2201 (pin 18) is doubled at
IC891d to obtain the band voltage for external equipment.
• Band selection data
3-4-2 SUB CPU PORT ALLOCATIONS
(DISPLAY board; IC1)
3 - 8
USB
LSB
CW
CW-R
RTTY
AM
FM
FM nar.
WFM9.0130
9.0100
9.0106
(–CW pitch frequency)
9.0106
(+CW pitch frequency)
9.008375 (2125 Hz tone)
9.008885 (1615 Hz tone)
No output
9.4665 (3rd LO)
9.4650 (3rd LO)
No output9.0130
9.0100
9.0106
(–CW pitch frequency)
9.0106
(+CW pitch freqency)
9.0105 (MARK)
9.0100
9.0115 (PLL ref.)
9.0100 (PLL ref.)
No output
ModeRX BFO/3rd LO TX BFO/FM PLL ref.
frequency [MHz] frequency [MHz]
0.03– 1.999999
2.0– 3.999999
4.0– 7.999999
8.0– 10.999999
11.0– 14.999999
15.0– 21.999999
22.0– 29.999999
30.0– 39.999999
40.0– 59.999999
60.0–128.999999
129.0–143.999999
144.0–148.000000
148.000001–
199.999999
400.000000–
470.000000
IC2231,
IC2201 IC101
IC2232
(MAIN) (PLL)
Frequency (MAIN)
[MHz]
HPF LPF 1/2 band
VCOLPF
BPF LPF voltage BPF
L1
L2
L3
L4
L5
L6
B7W
B7
B8
B9L1
L2
L3
L4
L5
L6
L7
L8
B93.70 V
3.19 V
2.68 V
0 V
2.18 V
1.69 V
1.19 V
0.96 VVCO1
VCO2
VCO1
VCO2
VCO3LOF1
LOF2
LOF3
LOF4
LOF5
LOF4
LOF6
1
18
19, 20
80
81
96
97
98
99Input port for the [SHIFT] control.
Outputs a PTT signal.
Low : While transmitting.
Outputs displaly backlight control sig-
nal.
Input port for the [PHONES] jack con-
nection detection.
High : When the headphone or
external speaker is connected
to the [PHONES] jack.
Input port for the [RIT] switch.
Input port for the [PTT] switch on the
microphone.
Input port for the microphone up/down
signal.
Input port for the [AF] control.
Input port for the [RF/SQL] control. SFTL
PTTS
BU1S,
BU2S
PHNK
RSK
PTTL
FUDL
AFGL
SQLL
Pin Port
Description
number name
3-4-3 I/O EXPANDER PORT ALLOCATIONS
(MAIN board; IC2221)
4
5
6
7
11, 12
13
14
Outputs select signal for the Tx AF
selector switch (IC1141).
Hign : When AM and SSB modes
are selected.
Outputs AM mode select signal.
High : When AM mode is selected.
Outputs FM and FM-N modes select
signal.
High : When FM and FM-N modes
are selected.
Outputs WFM mode select signal.
High : When WFM mode is selected.
Output select signals for the Rx AF
selector switch (IC861).
Outputs non-FM mode select signal.
High : When SSB/CW/RTTY/AM
modes are selected.
Outputs an audio mute signal for the
analog switch (IC971).
High :While transmitting in
CW/RTTY modes. MODS
AMS
FMS
WFMS
AFS1,
AFS2
UNFM
MINH
Pin Port
Description
number name
PORTMODE
WFM FM AM SSB/CW/RTTY
AFS1 High High Low Low
AFS2 High High Low Low 
						

							40
41
42
43
44
45
46
48
49–51
52
53
54
55
61
62
63
71
74
75
78
79Outputs 1750 Hz European tone sig-
nal.
Outputs a strobe signal for the option-
al UT-102 (Voice synthesizer unit).
Outputs serial data for the I/O
expanders, optional AT-180/UT-102.
Outputs a clock signal for the I/O
expanders, optional AT-180/ UT-102.
Outputs a strobe signal for the I/O
expander ICs (IC2231, IC2232).
Outputs a strobe signal for the I/O
expander ICs (IC2221, IC2222).
Outputs a strobe signal for the D/A
converter IC (IC2201).
Outputs a strobe signal for the BFO
DDS IC (PLL unit; IC901).
Output mode control signals for the 1st
LO DDS IC (PLL unit; IC101).
Outputs a strobe signal for the 1st LO
DDS IC (PLL unit; IC101).
Outputs a strobe signal for the 1st LO
PLL IC (PLL unit; IC461).
Outputs serial data for the DDS ICs
(PLL unit; IC101, IC901) and PLL IC
(PLL unit; IC461).
Outputs a clock signal for the DDS ICs
(PLL unit; IC101, IC901) and PLL IC
(PLL unit; IC461).
Outputs AGC rate select signal
Low : When AGC fast is selected.
Outputs the NB switch (Q635) control
slignal.
High : When the [NB] is turned ON,
except FM/WFM modes.
Outputs the attenuator circuit control
slignal.
High : When the [ATT] is turned ON.
Outputs a strobe signal for the TX FM
PLL IC (IC1011).
Input port for transmit/receive switch-
ing signals for the [ACC] connector.
Low : While transmitting.
Outputs a CW keying signal or RTTY
TX signal.
Output port for CI-V bus line.
Input port for CI-V bus line.
3 - 9ETON
MSST
MDT
MCK
BSTB
DSST
ASTB
PBST
CON2–
CON0
PDST
PMST
PDT
PCK
AFGS
NBS
ATTS
FMST
SNDS
KDS
LTXD
LRXD
(MAIN unit; IC2001)–Continued
Pin Port
Description
number name
13
14
15
16
17
18
19
20
21
22
23
24
30
31
32
33
34
37
39
Input port for the external paddle
(DASH).
Low : During key down
Input port for the external paddle
(DOT) or straight key.
Low : During key down
Input port for the PLL unlock signal
from the DDS IC (PLL unit; IC101) and
PLL IC (PLL unit; IC461).
Low : while PLL unlock
Input port for transmit control signal
from the optional AT-180/AH-4 anten-
na tuners.
Input port for the optional antenna
tuner connection detection.
High : When the optional antenna
tuner is connected.
Outputs a squelch control signal for
the external unit.
Input port for the [POWER] switch.
Low : When the [POWER] switch is
pushed.
Outputs the switching relay (PA unit;
RL591) control signal.
High : While power is ON.
Outputs start signal for the optional 
AT-180 antenna tuner.
Output port
: Beep audio signals while
receiving.
: CW side tone signals while
transmitting.
Outputs start signal for the optional
AH-4 
Outputs squelch mute control signal,
applied to the AF mute switch (MAIN
board; Q772).
Low : While squelch is closed.
Input port for the CTCSS decode sig-
nal from the low-pass filter (IC811C).
Input port from the [RTTY] or [MIC]
connector.
High : While transmitting.
Input port for the VOX voltage.
Input port for the anti-VOX voltage.
ALC level input port for the ALC meter
indication.
Outputs subaudible tone signals.
Input port for the optional UT-102
(Voice synthesizer unit) activation sig-
nal.
High : During speech synthesis.
3-4-4 MAIN CPU PORT ALLOCATIONS
(MAIN unit; IC2001)
DASK
DOTK
UNLK
TKEY
TCON
SQSS
PWK
POWS
ATST
BEEP
AHST
AFMS
CTCV
SNDL
VOXL
AVXL
ALCV
TONE
SPBK
Pin Port
Description
number name 
						

							4-1 PREPARATION BEFORE SARVICING
nREQUIRED TEST EQUIPMENT
DC power supply
RF power meter
(terminated type)
Frequency counter
RF voltmeter
Standard signal 
generator (SSG)
FM deviation meter
Modulation analyzerDistortion meter
Oscilloscope
Digital multimeter
AC millivoltmeter
DC voltmeter
DC ammeter
Audio generator
Spectram analyzer
Attenuator
External speaker
EQUIPMENT GREDE AND RANGE EQUIPMENT GREDE AND RENGE
4 - 1
SECTION 4 ADJUSTMENT PROCEDURES
Output voltage : 13.8 V DC
Current capacity : 30 A or more
Measuring range : 10–200 W
Frequency range : 1.8–500 MHz
Impedance : 50 ½
SWR : Less than 1.2 : 1
Frequency range : 0.1–500 MHz
Frequency accuracy : ±1 ppm or better
Sensitivity : 100 mV or better
Frequency range : 0.1–500 MHz
Measuring range : 0.01–10 V
Frequency range : 0.1–30 MHz
Output level : 0.1 µV–32 mV
(–127 to –17 dBm)
Frequency range : 0–500 MHz
Measuring range : 0 to ±5 kHz
Frequency range : At least 500 MHz
Measuring range : 0–100 %Frequency range : 1 kHz ±10 %
Measuring range : 1–100 %
Frequency range : DC–100 MHz
Measuring range : 0.01–10 V
Imput impeadance : 10 M½/DC or beter
Measuring range : 10 mV–10 V
Input impedance :
50 k½/V DC or better
Measurement capability: 1 A/50 A
Frequency range : 300–3000 Hz
Measuring range : 1–500 mV
Frequency range : At least 1000 MHz
Spectraum bandwidth : 100 kHz or more
Power attenuation : 50 or 60 dB
Capacity : 150 W or more
Input impedance : 8 ½
Capacity : 5 W or more
Ô ÔCONNECTIONS
Attenuator 
50 or 60 dB Audio 
generator
RF power meter 
A200 W/50 ½  DC power supply 
AA13.8 V/30 A
Standard signal 
aageneratorFM deviation 
AAmeter Spectrum 
analyzer AC
millivoltmeter
Modulation 
aanalyzer
CAUTION:
DO NOT connect the 
signal generator while 
transmitting.Speaker to [EXT SP]
i706MKIIG
to [MIC]
to [DC 13.8 V]
to [ELEC KEY]to [ANT 1/2]
Keyer • Microphone connector
• (Rear panel view)
Frequency counter
AM meter
1 A, 30 A
Pin 5
MIC GND
Pin 6 
MIC INPUT– 
+ 
Pin 4 
PTT 18
Pin 7 
GND 
						

							4-2 PLL ADJUSTMENTS
4 - 2
REFERENCE
FREQUENCY
REFERENCE
LOOP LOCK
VOLTAGE
MAIN LOOP
LOCK 
VOLTAGE
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITIONMEASUREMENT
VALUEPOINT
UNIT LOCATION UNIT ADJUST
1
2
1
1
2
3• Display frequency: Any
• L623 (PLL unit) : Center
• Receiving
• Display frequency: 0.0300 MHz
• Mode : USB
• Receiving
• Display frequency
: 128.99999 MHz
• Mode : USB
• Receiving
• Display frequency
: 199.99999 MHz
• Mode : USB
• Receiving
• Display frequency
: 470.00000 MHz
• Mode : USB
• ReceivingPLL
PLL
PLLConnect an RF volt-
meter to check point
P681.
Connect a frequency
counter to check
point P681.
Connect a digital
multimeter or oscillo-
scope to check point
CP131.
Connect a digital
multimeter or oscillo-
scope to check point
CP401.Maximum level
(0 dB or more)
60.000000 MHz
2.0 V
4.0 V
4.0 V
4.0 VPLL
PLL
PLLL681,
L682
L601
L623
R602
C4
C306
C335
C367
4-3 TRANSMITTER ADJUSTMENTS
TRANSMIT
TOTAL GAIN
OUTPUT
POWER
CARRIER
SUPPRESSION
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITIONMEASUREMENT
VALUEPOINT
UNIT LOCATION UNIT ADJUST
1
2
1
2
3
4
1• Display frequency: 14.10000 MHz
• Mode : USB
• [Q1 RF POWER] : H
• Connect an audio generator to
[MIC] connector and set as:
1.5 kHz/3 mV
• Transmitting
• Transmitting
• Display frequency: 14.10000 MHz
• Mode : USB
• [Q2 MIC GAIN] : 5
• Connect an audio generator to
[MIC] connector and set as:
1.5 kHz/30 mV
• Transmitting
• Display frequency
: 52.00000 MHz
• Transmitting
• Display frequency
: 145.00000 MHz
• Transmitting
• Display frequency
: 435.00000 MHz
• Transmitting
• Display frequency
: 14.10000 MHz
• Mode : USB and LSB
• Apply no signal to [MIC] connector.
• TransmittingRear
Panel
Rear
Panel
Rear
PanelConnect an RF
power meter to
[ANT1] connector.
Connect an RF
power meter to
[ANT1] connector.
Connect an RF
power meter to
[ANT2] connector.
Connect a spectrum
analyzer to [ANT1]
connector via an
attenuator.Maximum RF power
50 W
100 W
100 W
50 W
20 W
Minimum carrier levelMAIN
MAIN
MAINL511,
L512,
L562,
L563,
L566 
R579
R1082
R1084
R1086
R1088
R1045 
						

							4 - 3
• MAIN UNIT • PLL AND PA UNITS
CP131
CP401Reference loop lock 
voltage check pointReference frequency 
adjustment
C4
P681 L682
L681
C335 C306
C367
Main loop lock 
voltage adjustment Main loop lock 
voltage check point Reference loop lock 
voltage adjustment
Reference frequency 
check point 2nd LO level 
adjustment
R1082
R1084
R1086
R1088
R1045 L511
L512
L562
L563
L566 R579
L623
R602 L601
Transmit total gainOutput power
adjustment
Carrier suppression
adjustment 
						

							4 - 4
TRANSMITTER ADJUSTMENTS (continued)
FM VCO
FM
DEVIATION
RESIDUAL
AM
AM
MODULATION
CW 
CARRIER
LEVEL
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITIONMEASUREMENT
VALUEPOINT
UNIT LOCATION UNIT ADJUST
1
1
1
2
1
2
3
1• Display frequency: 29.10000 MHz
• Mode : FM
• [Q1 RF POWER] : H
• [M4 TON] : OFF
• Apply no signal to [MIC] connector.
• Transmitting
• Display frequency: 29.10000 MHz
• Mode : FM
• [Q1 RF POWER] : H
• [M4 TON] : OFF
• [Q2 MIC GAIN] : 5
• Connect an audio generator to
[MIC] connector and set as:
1 kHz/30 mV
• Transmitting
• Display frequency: 29.10000 MHz
• Mode : FM
• [Q1 RF POWER] : H
• [M4 TON] : OFF
• [Q2 MIC GAIN] : 5
• Connect an audio generator to
[MIC] connector and set as:
1 kHz/30 mV and OFF
• Transmitting
• Display frequency
: 14.10000 MHz
• Mode : AM
• [Q1 RF POWER] : H
• [Q2 MIC GAIN] : 5
• Disconnect the plug from J281 on
the MAIN board.
• Apply no signal to [MIC] connector.
• Transmitting
• Connect the plug to J281 on the
MAIN board.
• Apply no signal to [MIC] connector.
• Transmitting
• Connect an audio generator to
[MIC] connector and set as:
1 kHz/30 mV
• Transmitting
• Display frequency: 14.10000 MHz
• Mode : CW
• [Q1 RF POWER] : H
• [Q5 KEY SPEED] : 60
• [M4 BRK] : BK 
(semi break-in)
• CW paddle : n
• Connect an RF power meter to
[ANT1] connector.
• Transmit dots for a while using a
paddle.MAIN
Rear
Panel
MAIN
Rear
PanelConnect a digital
multimeter to check
point CP1011.
Connect an FM devi-
ation meter to [ANT1]
connector via an
attenuator.
Connect an RF
power meter to
[ANT1] connector.
Connect an osillo-
scope to check point
CP1041.
Connect an RF
power meter to
[ANT1] connector.
Connect a modula-
tion analyzer to
[ANT1] connector via
an attenuator.
Connect an osillo-
scope to check point
CP921 and [ANT1]
connector.1.8 V
±4.5 kHz
Minimum power differ-
ence with modulation
and unmodulation.
100 mVp-p
35 W
90 % modulation
At the point where the
CW carrier completely
comes up in a 10
msec. delay after
CP921 voltage comes
up.MAIN
MAIN
MAIN
MAIN
MAINC1022
R1002
adjust in
sequence
L511, L512,
then adjust
L562, L563,
L566.
R1042
R1080
R999
R921
After adjustment, varify the TRANSMIT TOTAL GAIN and OUTPUT POWER adjustments.
10 msec. Keying (CP921) 
						

							4 - 5
• MAIN UNIT
R921
R1042 R1002
R999
R1080 L511
L512 CP1011
CP1041
L562
L563
L566
Residual AM
adjustment FM VCO
check point
CP921CW carrier level
check point
AM modulation
check point
AM modulation
pre-settingFM deviation
adjustment
C1022FM VCO
adjustment
AM modulation
adjustment CW carrier level
adjustment
J281 
						

							4 - 6
TRANSMITTER ADJUSTMENTS (continued)
IDLING
CURRENT
(for drive
amplifiers)
(for final
amplifiers)
SWR
DETECTION
ADJUSTMENT
ADJUSTMENT ADJUSTMENT CONDITIONMEASUREMENT
VALUEPOINT
UNIT LOCATION UNIT ADJUST
1
2
3
4
5
1
2
3• Display frequency: 14.10000 MHz
• Mode : USB
• [Q2 MIC GAIN] : 1 (minimum)
• turn R162, R174, R175, R214,
R231 (on the PA unit) to maximum
counterclockwise position.
• Disconnect the plug from J571 on
the PA unit.
• Transmitting
• Display frequency: 145.10000 MHz
• Mode : USB
• [Q2 MIC GAIN] : 1 (minimum)
• Transmitting
• Display frequency: 14.10000 MHz
• Mode : USB
• [Q2 MIC GAIN] : 1 (minimum)
• Transmitting
• Transmitting
• Display frequency: 145.10000 MHz
• Mode : USB
• [Q2 MIC GAIN] : 1 (minimum)
• Transmitting
• Display frequency: 14.10000 MHz
• Mode : USB
• Ground CP1071 on the MAIN board.
• Connect an audio generator to
[MIC] connector and set as:
1.5 kHz/30 mV
• Transmitting
• TransmittingPA
Rear
Panel
FILTERConnect a DC
ammeter between
the DC power supply
and transceiver’s DC
power socket (P601
on the PA unit).
Connect an RF
power meter to
[ANT1] connector.
Connect a digital
multimeter to check
point W16.0.5 A increase from that
R162 is in maximum
counterclockwise posi-
tion.
1.0 A increase  from
step 1.
1.0 A increase from that
R174 is in maximum
counterclockwise posi-
tion.
1.0 A increase  from
step 3.
2.0 A increase  from
step 4.
100 W
Minimum voltagePA
Quick
set
mode
FILTERR162
R214
R174
R175
R231
Q2 MIC
GAIN
C58
After remove the jumper wire from CP1071 on the MAIN board.