Yaesu FT-991 Service Manual
Technical Supplement
HF/VHF/UHF ALL MODE TRANSCEIVER
FT-991
EH057M90B
©2015 YAESU MUSEN CO., LTD.
Introduction
This manual provides the technical information necessary
for servicing the FT-991 HF/VHF/UHF ALL MODE
TRANSCEIVER.
Servicing this equipment requires expertise in handing surface-mount chip components. Attempts by nonqualied persons to service this equipment may result
in permanent damage not covered by the warranty, and
may be illegal in some countries.
Two PCB layout diagrams provided for each doublesided board in this transceiver. Each side of the board
is referred to by the type of the majority of components
installed on that side ("Side A" or "Side B"). In most
cases one side has only chip components, and the other
has either a mixture of both chip and leaded components
(trimmers, coils, electrolytic capacitors, ICs, etc.), or
leaded components only.
While we believe the information in this manual to be
correct, YAESU assumes no liability for damage that
may occur as a result of typographical or other errors
that may be present. Your cooperation in pointing out
any inconsistencies in the technical information would
be appreciated.
Contents
Specications
Exploded View & Miscellaneous Parts
Block Diagram
Connection Diagram
Alignment
Board Unit (Schematics, Layouts & Parts)
MAIN Unit
PLL Unit
EDSP Unit
CNTL Unit
HF-PA Unit
V_U-PA Unit
PANEL Unit
FAN-CNTL Unit
TUNER Unit
JACK Unit
DSP Unit
Important Note
This transceiver was assembled using Pb (lead) free solder, based on the RoHS specication.
Only lead-free solder (Alloy Composition: Sn-3.0Ag-0.5Cu) should be used for repairs performed on this apparatus. The solder stated
above utilizes the alloy composition required for compliance with the lead-free specication, and any solder with the above alloy composition may be used.
Caution
Risk of explosion if battery is replaced by an incorrect type. Dispose of used batteries according to the instructions.
Specications
General
Rx Frequency Range: 30 kHz - 56 MHz, 118 MHz - 164 MHz, 420 MHz - 470 MHz (operating)
1.8MHz-54MHz,144MHz-148MHz,430MHz-450MHz(specied
performance,Amateurbandsonly)
Tx Frequency Ranges: 1.8 MHz - 54 MHz, 144 MHz - 148 MHz, 430 MHz - 450 MHz (Amateur
bandsonly)
Frequency Stability: ±0.5ppm(aer1minute@+14°Fto+122°F[–10°Cto+50°C])
Operating Temperature Range: +14°Fto+122°F(–10°Cto+50°C)
Emission Modes: A1A(CW),A3E(AM),J3E(LSB,USB),F3E(FM),F7W(C4FM),F2D
Frequency Steps: 5/10Hz(SSB,CW,&AM),100Hz(FM,C4FM)
Antenna Impedance: 50Ohms,unbalanced
16.7-150Ohms,unbalanced(TunerON,1.8MHz-30MHzAmateur
bands)
25-100Ohms,unbalanced(TunerON,50 MHz Amateurband)
Power Consumption(Approx.): Rx(nosignal) 1.8A
Rx(signalpresent) 2.2A
Tx 23A(HF/50MHz100W)
15A(144/430MHz50W)
Supply Voltage: DC13.8V±15%(NegativeGround)
Dimensions(WxHxD): 9.0”x3.2”x10.0”(229x80x253mm)
Weight(Approx.): 9.5lbs(4.3kg)
Transmier
Power Output: 5-100was(2-25wasAMcarrier)
Modulation Types: J3E(SSB):Balanced,
A3E(AM):Low-Level(EarlyStage),
F3E(FM):VariableReactance
F7W(C4FM):4-levelFSK
Maximum FM Deviation: ±5.0 kHz/±2.5 kHz
Harmonic Radiation: Beerthan–50dB(1.8MHz-30MHzAmateurbands)
Beerthan–63dB(30MHzAmateurband)
Beerthan–60dB(144MHz,430MHzAmateurbands)
SSB Carrier Suppression: Atleast50dBbelowpeakoutput
Undesired Sideband Suppression: Atleast50dBbelowpeakoutput
Bandwidth: 3kHz(LSB/USB),500Hz(CW),6kHz(AM),16kHz(FM/C4FM)
Audio Response(SSB): Notmorethan–6dBfrom300to2700Hz
Microphone Impedance: 600 Ohms (200 to 10 kOhms)
SPECIFICATIONS-1
FT-991 Technical Supplement
Specications
Receiver
Circuit Type: SSB/CW/AM:Triple-conversionSuperheterodyne
FM/C4FM:Double-conversionSuperheterodyne
Intermediate Frequencies: 40.455 MHz
SSB/CW/AM:69.450MHz/9.000MHz/24kHz
FM/C4FM:69.450MHz/450kHz
Sensitivity: SSB/CW(BW:2.4kHz,10dBS+N/N)
0.158µV(1.8-30MHz)(AMP2“ON”)
0.125µV(50-54MHz)(AMP2“ON”)
0.11µV(144-148MHz)
0.11µV(430-450MHz)
AM(BW:6kHz,10dBS+N/N,30%modulation@400Hz)
5µV(0.5-1.8MHz)(AMP2“ON”)
1.6µV(1.8-30MHz)(AMP2“ON”)
1.25µV(50-54MHz)(AMP2“ON”)
FM(BW:15kHz,12dBSINAD)
0.35µV(28-30MHz)(AMP2“ON”)
0.35µV(50-54MHz)(AMP2“ON”)
0.18µV(144-148MHz)
0.18µV(430-440MHz)
Thereisnospecicationforfrequencyrangesnotlisted.
Squelch Sensitivity (TYP.): SSB/CW/AM
1.0µV(1.8-30MHz,50-54MHz)(AMP2“ON”)
1.0µV(144-148MHz,430 - 450 MHz)
FM
0.35µV(28-30MHz,50-54MHz)(AMP2“ON”)
0.125µV(144-148MHz,430 - 450 MHz)
Thereisnospecicationforfrequencyrangesnotlisted.
Selectivity: Mode –6dB –60dB
CW/RTTY/PKT 0.5kHzorbeer 750Hzorless
SSB 2.4kHzorbeer 3.6kHzorless
AM 6kHzorbeer 15kHzorless
FM 12kHzorbeer 30kHzorless(–50dB)
Image Rejection: 70dBorbeer(1.8MHz-50MHzAmateurbands)
60dBorbeer(144/430MHzAmateurband)
Maximum Audio Output: 2.5Winto4Ohmswith10%THD
Audio Output Impedance: 4to8Ohms(4Ohms:nominal)
Conducted Radiation: Lessthan4nW
Specications are subject to change, in the interest of technical improvement, without notice or obligation,
and are guaranteed only within the amateur bands.
SPECIFICATIONS-2
FT-991 Technical Supplement
①
Exploded View
RA6024400
PORON SHEET(6x25)
①
①
R7153663
HIMERON
①
①
RA600120A
TOP CASE
①
①
①
RA6033500
GASKET (10x20)
②
RA6017300
SPONGE RUBBER(10x98)
②
RA0471500
ELEC. COND TAPE(C)
RA131710A
SPONGE RUBBER(SP-CE)
②
RA123330A
SHEEET
M4090229
SP 66S-A3627
②
RA0994000
PORON SHEET(151505)
②
③
③
③
②
②
②
③
RA6046900
BLIND SHEET (0715)
RA089840A
SP NET
②
②
RA6032500
DOUBLE FACE (19x9)
RA6032300
HEATSINK
RA6000700
SHIELD CASE COVER
②
RA6033500
GASKET (10x20)
②
RA1550600
SP HOLDER(H034M)
S5000260
LEAD CLAMP
④
R3520660A
HANDLE
④
R4150130
HANDLE END
REF. YAESU P/N Description Qty.
U31306007 OVAL HEAD SCREW M3X6B 8
①
U24206001 BIND HEAD TAPTITE-B M2.6X6 12
②
U31206007 OVAL HEAD SCREW M2.6X6B 4
③
U31415007 OVAL HEAD SCREW M4X15B 2
④
Non-designated parts are available only as psrt of a designated assembly.
EXPLODED VIEW-1
FT-991 Technical Supplement
S4000052
CASE LEG FF-004-AR791
Exploded View
①
②
①
R7153663
HIMERON
RA600110A
BOTTOM CASE
①
R0145630
STAND
R3100700A
FOOT
①
②
①
①
①
RA6024400
PORON SHEET(6x25)
①
RA0423200
LOCK PLATE
RA089560A
GASKETW9H4L40
①
RA1236600
PORON SHEET(10X10t3)
RA6048700
GASKET(70x70)
③
③
RA6000800
SHIELD CASE COVER
③
③
RA6033500
GASKET (10x20)
REF. YAESU P/N Description Qty.
U31306007 OVAL HEAD SCREW M3X6B 9
①
U20406007 BINDING HEAD SCREW M4X6B 2
②
U30305002 FLAT HEAD SCREW M3X5NI 4
③
Non-designated parts are available only as psrt of a designated assembly.
EXPLODED VIEW-2
FT-991 Technical Supplement
Exploded View
RA6003500
RUBBER KNOB(PWR)
Q7000653
LCD MODULE
RA1340000
LCD SPACER (A)
RA6003400
LCD SPACER(57B)
PANEL-UNIT
①
RA6030000
GASKET(8x10)
①
①
①
①
①
①
JACK-UNIT
①
①
①
①
①
Q9001000
ROTARY ENCODER
①
RA6025300
BLIND SHEET(9x28)
RA6018200
NAME PLATE
U62009001
VOLUME NUT 9X12X2
RA6004600
KNOB SKIRT
RA6003200
WINDOW(LED)
RA6004000
KNOB ASSY (ENC)
Q9000996
ROTARY ENCODER (w/ ø1, ø2)
RA6054500
PORON SHEET(10x3.5) (2 pcs)
Q9000758
ROTARY ENCODER (w/ ø1, ø2)
RA6003600
RUBBER KNOB(H057)
ø
2
ø
1
ø
ø
ø
2
1
RA600300A
FRONT PANEL(PRT)
ø
2
1
RA6025300
BLIND SHEET(9x28)
J60800322
POT (w/ ø1, ø2)
RA1528400
WASHER(PE)
RA6004500
RUBBER RING(MAIN)
②
②
RA152820A
WASHER(FELT)
RA6004200
KNOB MAIN ASSY
U9900211
WAVE WASHER WW-16011(SUS)
RA0979300
HOLDER(SPRING)
RA6003700
KNOB ASSY(VOL)
U70015001
PLAIN WASHER FW9X14X0.5
ø
ø
2
1
REF. YAESU P/N Description Qty.
U24108001 BIND HEAD TAPTITE-B M2X8(3) 13
①
U24206001 BIND HEAD TAPTITE-B M2.6X6 2
②
Non-designated parts are available only as psrt of a designated assembly.
EXPLODED VIEW-3
FT-991 Technical Supplement
RA602540A
PORON SHEET (10x115)
Exploded View
RA6000300
CHASSIS
RA6000900
SHIELD CASE COVER
RA1499500
PORON SHEET(25x35)
RA1559100
GASKET(5x12) (3 pcs)
①
①
②
③
CNTL-UNIT
②
①
②
②
RA1391800
SPACER(DSP)
DSP-UNIT
②
②
②
RA6015300
GASKET(120x10)
RA602550A
PORON SHEET (10x85)
RA0060200
SHIELD CASE
RA1558800
GASKET(60x12)
②
EDSP-UNIT
②
①
RA6001000
RUBBER PACKING
①
①
②
REF. YAESU P/N Description Qty.
U34206001 FLAT HEAD TAPTITE-B M2.6X6 6
①
U24206001 BIND HEAD TAPTITE-B M2.6X6 10
②
U24208007 BIND HEAD TAPTITE-B M2.6X8B 1
③
Non-designated parts are available only as psrt of a designated assembly.
EXPLODED VIEW-4
FT-991 Technical Supplement
①
②
①
RA6035100
LEAF SPRING
①
①
①
①
④
④
S5000331
TERMINAL
R0131680
SHIELD COVER
①
Exploded View
①
⑤
HF-PA-UNIT
②
③
①
③
①
③
②
①
④
③
RA0415200
GROUND PLATE (4 pcs)
①
①
③
③
①
①
①
①
③
④
①
①
R0131670A
SHIELD CASE
①
③
①
①
①
①
RA6032400
Thermal Conductive Pad
①
RA6049000
Thermal Conductive Pad
①
V_U-PA-UNIT
M2090052
FAN
⑥
⑥
P1091158A
CONNECTOR
S5000320
FAN GUARD
⑥
⑥
⑤
⑤
⑤
P1091158A (CE OFF)
P1090547 (CE ON)
CONNECTOR
⑦
S5000236 (CE ON)
LUG WASHER FOR MDR-2
RA6000400
DISPLAY PANEL
REF. YAESU P/N Description Qty.
U24206001 BIND HEAD TAPTITE-B M2.6X6 26
①
U24208007 BIND HEAD TAPTITE-B M2.6X8B 3
②
U03310002 SEMS SCREW ASM3X10NI 8
③
U03306002 PAN HEAD SCREW ASM3X6NI 4
④
U04333007 SEMS SCREW HSM3X33B 4
⑤
U24306001 BIND HEAD TAPTITE-B M3X6 4
⑥
U04410002 SEMS SCREW HSM4X10NI 1
⑦
EXPLODED VIEW-5
Non-designated parts are available only as psrt of a designated assembly.
FT-991 Technical Supplement
①
Exploded View
RA1152400
SHIELD CASE COVER
RA6001700
SHIELD CASE COVER
PLL-UNIT
①
②
①
RA6002100
SHIELD PLATE
②
①
RA1152300
SHIELD CASE COVER
RA0659300
SHIELD CASE
②
②
②
②
RA0830400
SHIELD CASE COVER
②
②
②
MAIN-UNIT
②
RA6032400
Thermal Conductive Pad
S5000260
LEAD CLAMP CC-1002
②
RA1152200
SHIELD CASE(28x15)
③
②
RA0830300
SHIELD CASE(21X25)
③
③
③
TUNER-UNIT
③
RA6015400
GASKET(80x10)
RA6025100
Thermal Conductive Pad
RA6025200
Thermal Conductive Pad
REF. YAESU P/N Description Qty.
U03306002 PAN HEAD SCREW ASM3X6NI 4
①
U24206001 BIND HEAD TAPTITE-B M2.6X6 12
②
U24306001 BIND HEAD TAPTITE-B M3X6 5
③
Non-designated parts are available only as psrt of a designated assembly.
EXPLODED VIEW-6
FT-991 Technical Supplement
Block Diagram
BLOCK DIAGRAM-1
FT-991 Technical Supplement
Connection Diagram
CONNECTION DIAGRAM-1
FT-991 Technical Supplement
Alignment
Introduction and Precautions
The following procedures cover adjustments that
are not normally required once the transceiver
has le the factory. However, if a problem occurs
during normal operation due to component failure;
realignment may be required aer the faulty components have been replaced.
We recommend that authorized Yaesu Techni-
cians, who are experienced with the circuitry and
fully equipped to repair and align our products,
perform repairs. If a fault is suspected, contact the
selling dealer for instructions regarding repair.
Authorized Yaesu Technicians have the latest information to align all circuits and make complete performance checks to ensure compliance with factory
specications aer repairs.
Those who do undertake any of the following
alignments are cautioned to proceed at their own
risk. Problems caused by unauthorized aempts at
realignment are not covered by the warranty policy.
Yaesu must reserve the right to change circuits and
alignment procedures in the interest of improved
performance, without notifying owners.
Under no circumstances should any alignment be
aempted unless the normal functions and operation of the transceiver are clearly understood, the
cause of the malfunction has been clearly identied
and all faulty components replaced. The need for
realignment should be determined to be absolutely
necessary.
The following test equipment (and a thorough familiarity with its correct use) is necessary for cor-
rect realignment. Most steps do not require all of
the equipment listed. The interactions of some adjustments may require that more complex adjustments be performed in a sequence. Do not aempt
to perform only a single step unless it is clearly iso-
lated electrically from all other steps. Have all test
equipment ready before beginning, and follow all
of the steps in a section in the order they are pre-
sented.
Required Test Equipment
RF Signal Generator
AF Signal Generator
Spectrum Analyzer good to at least 1 GHz.
Frequency Counter
SINAD Meter
RF Millivoltmeter
Electronic Load
Digital DC Voltmeter (high-Z, 1 M-Ohm/V)
DC Voltmeter
DC Ammeter (23 A)
Ohmmeter
50-Ohm Dummy Load (100/200 was)
In-Line Wameter (150/300 was, 50-Ohm)
Linear Detector
RF Coupler
4-Ohm AF Dummy Load (3 was)
1/4-inch 3-contact Plug
Alignment Preparation & Precautions
A 50-ohm RF Dummy load and in-line wameter
must be connected to the ANT jack in all procedures that call for transmission, except where specied otherwise. Correct alignment is not possible
with an antenna.
Aer completing one step, read the following step
to determine whether the same test equipment
will be required. If not, remove the unneeded test
equipment before proceeding. (except the dummy
load and wameter).
Correct alignment requires that the ambient temperature be maintained constant between 68 °F ~ 86
°F (20 °C ~ 30 °C). When the transceiver is brought
into the shop from a hot or cold environment, it
should be allowed time to come to room temperature before alignment. Also, the test equipment
must be thoroughly warmed up before beginning.
Whenever possible, alignments should be made
with oscillator shields and circuit boards rmly afxed in place.
Note: Signal levels in dB referred to in this proce-
dure are based on 0 dBµ = 0.5 µV (closed circuit).
Important Notice
Do not adjust the alignment menus that are
not mentioned in this manual.
ALIGNMENT-1
FT-991 Technical Supplement
Alignment
VDD Meter Adjustment
Connect the DC voltmeter to J4006 on the HF-
PA-Unit.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] dial knob to select the
alignment menu item “01-01 VDD MTR”.
Press the [F(M-LIST)] key, then rotate the
[CLAR/VFO-B] knob so the VDD meter reading
is the same as the reading on the DC voltmeter
(13.8 V).
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
COMP Meter Adjustment
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “22-02 COMP MTR
10dB”, then rotate the [CLAR/VFO-B] knob for
"10 dB" on the COMP meter.
Rotate the [MULTI] Dial knob to select the
alignment menu item “22-03 COMP MTR
20dB”, then rotate the [CLAR/VFO-B] knob for
"20 dB" on the COMP meter.
Rotate the [MULTI] Dial knob to select the
alignment menu item “22-04 COMP MTR
30dB”, then rotate the [CLAR/VFO-B] knob so
the COMP meter deects to full scale.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seings and exit
the alignment mode.
J4006
ALIGNMENT-2
FT-991 Technical Supplement
Alignment
VCO Adjustment
Connect the Digital DC voltmeter (high-Z) to
TP2002 on the PLL Unit.
Disconnect the coaxial cable from J2001 on the
PLL Unit, then connect the RF millivoltmeter to
pin 13 of J2001.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Referring to the table below, select the appropri-
ate “Alignment menu item” using the [MULTI]
Dial knob per the chart right, and adjust the
listed components for the required voltage, or
confirm that the correct voltage is present on
each alignment menu item.
Alignment
Menu Item
01-05 VCO1-HIGH
(TXI)
01-06 VCO1-LOW Conrm At least 0.3 V At least –10 dBm
01-07 VCO2-HIGH
01-08 VCO2-LOW Conrm At least 0.6 V At least –10 dBm
01-09 VCO3-HIGH
01-10 VCO3-LOW Conrm At least 0.4 V At least –10 dBm
01-11 VCO4-HIGH
01-12 VCO4-LOW Conrm At least 0.5 V At least –10 dBm
01-13 VCO5-HIGH
01-14 VCO5-LOW Conrm At least 0.8 V At least –10 dBm
Disconnect the RF millivoltmeter from J2001,
Adjust /
Conrm
Adjust
L2004
Adjust
L2005
Adjust
L2006
Adjust
TC2001
Adjust
TC2002
DC voltmeter RF millivoltmeter
5.1 V ±0.1 V At least 3 dBm
5.1 V ±0.1 V At least –10 dBm
4.1 V ±0.1 V At least –10 dBm
5.0 V ±0.1 V At least –10 dBm
5.0 V ±0.1 V At least –10 dBm
then re-connect the coaxial cable to J2001.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
TP2002
TC2001
TC2002L2006L2005L2004
J2001
ALIGNMENT-3
FT-991 Technical Supplement
Alignment
2nd/3rd Local Oscillator Adjustment
Set the VFO-A frequency to 14.200 MHz in the
CW-USB mode.
Set the following controls as indicated:
[IPO] : AMP1
[ATT] : OFF
[NB] : OFF
[AGC] : AUTO
[RF GAIN] : Fully clockwise
3rd Local Level Adjustment
Connect the RF millivoltmeter to TP1024 on the
MAIN Unit.
Adjust T1029 on the MAIN Unit for maximum
deection on the RF millivoltmeter.
2nd
Local Level Adjustment
Connect the RF millivoltmeter to TP1025 on the
MAIN Unit.
Adjust T1027, T1028, T1030, and T1033 on the
MAIN Unit for maximum deection on the RF
millivoltmeter.
TP1005
TP1024
TP1025
T1033
T1030
TC1006
TP1008
T1028
T1027
T1029
ALIGNMENT-4
FT-991 Technical Supplement
Alignment
REF OSC Adjustment
Connect the frequency counter to TP1025.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “01-04 REF FREQ”.
Rotate the [CLAR/VFO-B] knob so that the
frequency counter reading is “60.450000 ±4
Hz”.
Disconnect the frequency counter from TP1025.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
FM Local Oscillator Adjustment
Set the FM mode.
Connect the Digital DC voltmeter (high-Z)
TP1008 on the MAIN Unit.
Adjust TC1006 on the MAIN Unit for 3.6 V ±0.1
V on the Digital DC voltmeter.
Set the CW mode.
TP1025
TC1006
TP1008
ALIGNMENT-5
FT-991 Technical Supplement
1st Local Oscillator Adjustment
Connect the RF millivoltmeter to TP1005 on the
MAIN Unit.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-01 Local 1.8”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+10 dBm ±1 dBm”.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-02 Local HFL”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+10 dBm ±1 dBm”.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-03 Local HFM”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+10 dBm ±1 dBm”.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-04 Local HFH”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+10 dBm ±1 dBm”.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-05 Local 50”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+11.5 dBm ±0.5 dBm”.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-06 Local 144”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+10 dBm ±1 dBm”.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “02-07 Local 430”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob so that the RF millivoltmeter reading is “+10 dBm ±1 dBm”.
Release the PTT buon.
Alignment
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seings and exit
the alignment mode.
Alignment
Menu Item
02-01 Local 1.8 +10 dBm ±1 dBm
02-02 Local HFL +10 dBm ±1 dBm
02-03 Local HFM +10 dBm ±1 dBm
02-04 Local HFH +10 dBm ±1 dBm
02-05 Local 50 +11.5 dBm ±0.5 dBm
02-06 Local 144 +10 dBm ±1 dBm
02-07 Local 430 +10 dBm ±1 dBm
RF millivoltmeter
ALIGNMENT-6
TP1005
FT-991 Technical Supplement
Alignment
MCF Adjustment (1)
Set the VFO-A frequency to 145.900 MHz in the
CW-USB mode.
Set the following controls as indicated:
[AGC] : AUTO
[RF GAIN] : Fully clockwise
Connect the AF millivoltmeter and 4 Ohm
dummy load to the EXT SP jack.
Connect the RF Signal Generator to the “144/430
MHz” ANT jack, then set the output level to +0
dBµ at the 145.900 MHz.
Adjust T1001, T1003 and T1025, T1026 on the
MAIN Unit in succession several times for
maximum deection on the AF millivoltmeter.
Note: If the S-meter deflects while adjusting,
reduce the RF Signal Generator output so that the
S-meter does not deect.
Set the FM mode.
Connect the SINAD meter and 4 Ohm dummy
load to the EXT SP jack.
Connect the RF Signal Generator to the “144/430
MHz” ANT jack, then set the output level to –9
dBµ at the 145.900 MHz with ±3.5 kHz deviation FM modulation of a 1 kHz audio signal.
Adjust T1025 on the MAIN Unit in succession
several times for maximum deflection on the
SINAD meter.
Note: Do not adjust T1025 more than 180 degrees
rotation.
MCF Adjustment (2)
Set the VFO-A frequency to 439.900 MHz in the
CW-USB mode.
Set the following controls as indicated:
[AGC] : AUTO
[RF GAIN] : Fully clockwise
Connect the AF millivoltmeter and 4 Ohm
dummy load to the EXT SP jack.
Connect the RF Signal Generator to the “144/430
MHz” ANT jack, then set the output level to +0
dBµ at the 439.900 MHz.
Adjust TC1001 and TC1007 on the MAIN
Unit in succession several times for maximum
deection on the AF millivoltmeter.
Note: If the S-meter deflects while adjusting,
reduce the RF Signal Generator output so that the
S-meter does not deect.
T1001
T1003
TC1001
TC1007
ALIGNMENT-7
T1025
T1026
FT-991 Technical Supplement
Alignment
IF Trap Adjustment
Set the VFO-A frequency to 51.900 MHz in the
CW-USB mode.
Set the following controls as indicated:
[IPO] : AMP2
[ATT] : OFF
[AGC] : AUTO
[RF GAIN] : Fully clockwise
Connect the AF millivoltmeter and 4 Ohm
dummy load to the EXT SP jack.
Connect the RF Signal Generator to the “HF/50
MHz” ANT jack, then set the output level to
+40 ~ +80 dBµ at the 69.450000 MHz.
Adjust T1017 on the MAIN Unit for minimum
deection on the AF millivoltmeter.
Note: If the S-meter deflects while adjusting,
reduce the RF Signal Generator output so that the
S-meter does not deect.
RF AGC Adjustment
Set the VFO-A frequency to 14.200 MHz in the
CW-USB mode.
Set the following controls as indicated:
[IPO] : AMP1
[ATT] : OFF
[AGC] : AUTO
[RF GAIN] : Fully clockwise
Connect the RF Signal Generator to the "HF/50
MHz" ANT jack, then set the output level to
+76dBµ at the 14.200 MHz.
Connect the Digital DC voltmeter (high-Z) to
TP1016 on the MAIN Unit.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “03-03 RF-AGC HFM”.
Adjusting the [CLAR/VFO-B] knob so the Digi-
tal DC voltmeter reading is "2.6 V ±0.2 V".
Set to the same parameter of the alignment
menu item “03-03 RF-AGC HFM” for the Alignment Menu items “03-01 RF-AGC 1.8”, “03-02
RF-AGC HFL”, “03-04 RF-AGC HFH”, “03-05
RF-AGC 50”, “03-06 RF-AGC 144” and “03-07
RF-AGC 430”
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
TP1016
T1017
ALIGNMENT-8
FT-991 Technical Supplement
IF Gain Adjustment
Set the following controls as indicated:
[IPO] : AMP1
[ATT] : OFF
[AGC] : AUTO
[RF GAIN] : Fully clockwise
Connect the AF millivoltmeter and 4 Ohm
dummy load to the EXT SP jack.
Connect the RF Signal Generator to the “HF/50
MHz” ANT jack, then set the output level to
+36 dBµ at 1.900 MHz.
Set the VFO-A frequency to 1.900 MHz in the
USB mode.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Adjust the [AF GAIN] knob so that the AF mil-
livoltmeter reading is “0 dB”.
Set the RF Signal Generator output level to +10
dBµ.
Adjust the [CLAR/VFO-B] knob so that the AF
millivoltmeter reading is “-1.5 ± 0.5 dB”.
Select the appropriate “Alignment menu item”
using the [MULTI] Dial knob per the chart below, then set the RF Signal Generator output to
each frequency & level, and adjust the [CLAR/
VFO-B] knob for the corresponding AF millivoltmeter reading at each frequency.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seings and exit
the alignment mode.
Alignment
Alignment
menu item
04-01 IGC 1.8 1.900 MHz
04-02 IGC HFL 7.100 MHz
04-03 IGC HFM 14.200 MHz
04-04 IGC HFH 21.230 MHz
04-05 IGC 50 51.900 MHz
04-06 IGC 144 145.900 MHz
04-07 IGC 430 439.900 MHz
VFO-A
Frequency
RF Signal
Generator
1.900 MHz, +36 dBµ
1.900 MHz, +10 dBµ
7.100 MHz, +36 dBµ
7.100 MHz, +10 dBµ
14.200 MHz, +36 dBµ
14.200 MHz, +10 dBµ
21.230 MHz, +36 dBµ
21.230 MHz, +10 dBµ
51.900 MHz, +36 dBµ
51.900 MHz, +7 dBµ
145.900 MHz, +30 dBµ
145.900 MHz, -3 dBµ
439.900 MHz, +30 dBµ
439.900 MHz, -3dBµ
ALIGNMENT-9
Adjust AF millivoltmeter
[AF GAIN] knob
[CLAR/VFO-B] knob
[AF GAIN] knob
[CLAR/VFO-B] knob
[AF GAIN] knob
[CLAR/VFO-B] knob
[AF GAIN] knob
[CLAR/VFO-B] knob
[AF GAIN] knob
[CLAR/VFO-B] knob
[AF GAIN] knob
[CLAR/VFO-B] knob
[AF GAIN] knob
[CLAR/VFO-B] knob
-1.5 dB (±0.5 dB)
-1.5 dB (±0.5 dB)
-1.5 dB (±0.5 dB)
-1.5 dB (±0.5 dB)
-1.5 dB (±0.5 dB)
-1.5 dB (±0.5 dB)
-1.5 dB (±0.5 dB)
0 dB
0 dB
0 dB
0 dB
0 dB
0 dB
0 dB
FT-991 Technical Supplement
Alignment
S-meter Adjustment
Set the VFO-A frequency to 14.200 MHz in the
USB mode.
Set the following controls as indicated:
[IPO] : AMP1
[ATT] : OFF
[AGC] : AUTO
[RF GAIN] : Fully clockwise
Connect the RF Signal Generator to the “HF/50
MHz” ANT jack, then set the frequency to
14.200 MHz.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Refer to the chart below and select the
appropriate “Alignment menu item” using the
[MULTI] Dial knob. Set the RF Signal Generator
output to each level, and adjust the [CLAR/
VFO-B] knob for the corresponding S-meter
reading. Press the [F(M-LIST)] key to save the
new seing at each level.
Alignment menu item RF Signal Generator S-meter
05-01 S-MTR 0 OFF S-0
05-02 S-MTR 1 +14 dBµ S-1
05-03 S-MTR 5 +24 dBµ S-5
05-04 S-MTR 7 +30 dBµ S-7
05-05 S-MTR 9 +36 dBµ S-9
05-06 S-MTR +10 +46 dBµ S-9+10dB
05-07 S-MTR +20 +56 dBµ S-9+20dB
05-08 S-MTR +30 +66 dBµ S-9+30dB
05-09 S-MTR +40 +76 dBµ S-9+40dB
05-10 S-MTR +50 +86 dBµ S-9+50dB
05-11 S-MTR +60 +96 dBµ S-9+60dB
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seings and exit
the alignment mode.
S-meter Adjustment (FM)
Set the VFO-A frequency to 145.900 MHz in the
FM mode.
Connect the RF Signal Generator to the “144/430
MHz” ANT jack, then set the output level to 0
dBµ at the 145.900 MHz with ±3.5 kHz deviation FM modulation of a 1 kHz audio signal.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “07-01 FM S1”.
Rotate the [CLAR/VFO-B] knob so that the
S-meter reading is “S-1”.
Press the [F(M-LIST)] button to save the new
seing.
Set the RF Signal Generator to +20 dBµ.
Rotate the [MULTI] Dial knob to select the
alignment menu item “07-02 FM S9”.
Rotate the [CLAR/VFO-B] knob so that the
S-meter reading is “S-9”.
Press the [F(M-LIST)] button to save the new
seing.
Set the RF Signal Generator to +40 dBµ.
Rotate the [MULTI] Dial knob to select the
alignment menu item “07-03 FM S60”.
Rotate the [CLAR/VFO-B] knob so that the
S-meter reading is “S-9+60”.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
FIL Gain Adjustment
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “06-01 R. FIL 3k”.
Rotate the [CLAR/VFO-B] knob to set the pa-
rameter is "180".
Rotate the [MULTI] Dial knob to select the
alignment menu item “06-02 R. FIL 15k”.
Rotate the [CLAR/VFO-B] knob to set the pa-
rameter is "180".
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seings and exit
the alignment mode.
ALIGNMENT-10
FT-991 Technical Supplement
Alignment
FM Squelch Adjustment
Set the VFO-A frequency to 145.900 MHz in the
FM-WIDE mode.
Connect the RF Signal Generator to the “144/430
MHz” ANT jack, then set the output level to -14
dBµ at the 145.900 MHz with ±3.5 kHz deviation FM modulation of a 1 kHz audio signal.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “08-01 FM SQL THW”.
Press the [F(M-LIST)] button to save the new
seing.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
Set the FM-NARROW mode.
Set the RF Signal Generator output level to -14
dBµ at the 145.900 MHz with ±1.75 kHz deviation FM modulation of a 1 kHz audio signal.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “08-02 FM SQL THN”.
Press the [F(M-LIST)] button to save the new
seing.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
Set the FM-WIDE mode.
Set the RF Signal Generator output level to +3
dBµ at the 145.900 MHz with ±3.5 kHz deviation FM modulation of a 1 kHz audio signal.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “08-03 FM SQL TI”.
Press the [F(M-LIST)] button to save the new
seing.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
FM Center Stop Adjustment
Set the VFO-A frequency to 145.900 MHz in the
FM-WIDE mode.
Connect the RF Signal Generator to the “144/430
MHz” ANT jack, then set the output level to
+10 dBµ at the 145.900 MHz.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “09-01 FM CTR-L”.
Press the [F(M-LIST)] button to save the new
seing.
Set the RF Signal Generator to 145.903 MHz.
Rotate the [MULTI] Dial knob to select the
alignment menu item “09-02 FM CTR-H”.
Press the [F(M-LIST)] button to save the new
seing.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
ALIGNMENT-11
FT-991 Technical Supplement
Transmier Adjustment
TX IFT Adjustment
Disconnect the coaxial cable from J1004 on the
MAIN Unit, then connect the RF millivoltmeter
to J1004.
Set the VFO-A frequency to 14.200 MHz in the
CW-USB mode.
Set the TX Power to 100 W.
Connect the Microphone to the front panel MIC
jack.
Press the PTT button, adjust T1024, T1022,
T1021 and T1018 for maximum deflection on
the RF millivoltmeter.
Release the PTT buon.
Set the VFO-A frequency to 145.900 MHz in the
FM mode.
Press the PTT buon, adjust T1008, T1007 and
T1006 for maximum deection on the RF millivoltmeter.
Alignment
Release the PTT buon.
Set the VFO-A frequency to 439.900 MHz in the
FM mode.
Press the PTT button, adjust TC1004, TC1003
and TC1002 for maximum deection on the RF
millivoltmeter.
Release the PTT buon.
Disconnect the RF millivoltmeter from J1004 on
the MAIN Unit, then connect the Spectrum Analyzer to J1004.
Set the VFO-A frequency to 52.000 MHz in the
CW-USB mode.
Press the PTT buon, adjust T1005 on the spu-
rious (69.450 MHz) for minimum deection on
the Spectrum Analyzer.
Release the PTT buon.
Disconnect the Spectrum Analyzer from J1004,
then re-connect the coaxial cable to J1004.
T1005
TC1002
T1006
TC1003
T1007
T1008
TC1004
J1004
T1018
T1021
T1022
T1024
ALIGNMENT-12
FT-991 Technical Supplement
Alignment
V-U PA Unit Adjustment
Preparation
Connect the Microphone to the front panel MIC
jack.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “144/430 MHz” ANT jack.
Disconnect the coaxial cables from J4501 and
J4502 on the V_U-PA Unit, then terminate J4501
and J4502, each with a 50-Ohm resistor.
Disconnect the jumper plugs from J4505, J4506
and J4507 on the V_U-PA Unit.
Disconnect the red cable from J4503 on the V_
U-PA Unit.
J4501J4502
Pre-Drive Stage Idling Current Adjustment
Connect the DC ammeter to J4505 on the V_
U-PA Unit.
Press and hold the PTT button, while adjust
VR4501 so the DC ammeter reading is “40 mA
(±5 mA)”.
Release the PTT buon.
Disconnect the DC ammeter from J4505.
J4507 J4503
J4505 VR4501J4506
ALIGNMENT-13
FT-991 Technical Supplement
Alignment
Drive Stage Idling Current Adjustment
Connect the DC ammeter to J4506 on the V_
U-PA Unit.
Press and hold the PTT button, while adjust
VR4502 so the DC ammeter reading is “100 mA
(±10 mA)”.
Release the PTT buon.
Disconnect the DC ammeter from J4506.
Re-connect the red cable to J4503 on the V_
U-PA Unit.
Semi-Final Stage Idling Current Adjustment
Connect the DC ammeter to J4507 on the V_
U-PA Unit.
Press and hold the PTT button, while adjust
VR4505 so the DC ammeter reading is “600 mA
(±50 mA)”.
Adjust VR4506 so the DC ammeter reading is
“1.2 A (±0.1 A)”.
Release the PTT buon.
Disconnect the DC ammeter from J4507.
Final Stage Idling Current Adjustment
Disconnect the red cable from J4503 on the V_
U-PA Unit.
Connect the DC ammeter between J4503 and
red cable.
Press and hold the PTT button, while adjust
VR4503 so the DC ammeter reading is “800 mA
(±50 mA)”.
Release the PTT buon.
Disconnect the DC ammeter from J4503 and red
cable, then connect the red cable to J4503.
Disconnect the 50-Ohm resistors from J4501
and J4502, then connect the coaxial cables to
J4501 and J4502.
Re-connect the jumper plugs to J4505, J4506 and
J4507.
V_U-PA Unit TX Adjustment
Set the VFO-A frequency to 439.990 MHz in the
USB mode.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “144/430 MHz” ANT jack.
Connect the Audio Generator to pin 8 of the
MIC jack (pin 7: GND), then set the output level
to 0.5 mV @1 kHz.
Press the PTT buon, then adjust the MIC gain
to set the RF Power output to 25 W on the Wameter.
Press the PTT buon, adjust TC4501 for maxi-
mum deection on the Wameter.
Release the PTT buon.
J4501J4502
VR4505
J4507 J4503
VR4502 VR4506J4506
J4505 TC4501
ALIGNMENT-14
VR4503
FT-991 Technical Supplement
HF PA Unit Adjustment
Preparation
Connect the Microphone to the front panel MIC
jack.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “HF/50 MHz” ANT jack.
Disconnect the coaxial cables from J4001 on the
HF-PA Unit, then terminate J4001 with a 50Ohm resistor.
Connect the DC ammeter between J4006 and
J4007.
Disconnect the jumper plugs from J4004 and
J4005 on the HF-PA Unit.
Re-connect the jumper plugs to J4004.
Alignment
Press and hold the PTT button, while adjust
VR4001 so the DC ammeter reading is “1.5 A
(±0.1 A)”.
ReleasethePTTbuon.
Disconnect the jumper plugs from J4004.
Re-connect the jumper plugs to J4005.
Press and hold the PTT button, while adjust
VR4002 so the DC ammeter reading is “1.5 A
(±0.1 A)”.
ReleasethePTTbuon.
Re-connect the jumper plugs to J4004.
Disconnect the DC ammeter from J4006 and
4007.
Disconnect the 50-Ohm resistors from J4001 ,
then connect the coaxial cable to J4001.
ALIGNMENT-15
J4006 J4007J4004 VR4001J4001 J4005VR4002
FT-991 Technical Supplement
Alignment
CM Coupler Balance Adjustment
Connect the 50-Ohm Dummy Load and Watt-
meter to the “HF/50 MHz” ANT jack.
Connect the Digital DC voltmeter (high-Z) to
pin 2 of J4013 on the HF-PA Unit.
Turn o the [TUNE] switch, then set the VFO-A
frequency to 24.900 MHz in the USB mode.
Press the PTT buon, then adjust the MIC gain
to set the RF Power output to 50 W on the Wameter.
Press the PTT buon, adjust TC4001 for mini-
mum deection on the DC voltmeter (less than
0.1 V).
Release the PTT buon.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “144/430 MHz” ANT jack.
Set the VFO-A frequency to 430.000 MHz.
Press the PTT buon, then adjust the MIC gain
to set the RF Power output to 25 W on the Wameter.
Press the PTT buon, adjust VR4507 for mini-
mum deection on the DC voltmeter (less than
0.3 V).
Release the PTT buon.
TC4001J4013
ALIGNMENT-16
VR4507
FT-991 Technical Supplement
Current ALC Adjustment
If the Main Firmware version of your
transceiver is “V10-13 or later”, see next
section.
Connect the Microphone to the front panel MIC
jack.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “HF/50 MHz” ANT jack.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-01 I-ALC 1.8” for the
1.8 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 1.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "33".
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“5” in-crease.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-02 I-ALC HFL” for
the 7 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 7.10 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "39".
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-03 I-ALC HFM” for
the 14 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 14.20 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "37".
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-04 I-ALC HFH” for
the 21 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 21.240 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "37".
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-05 I-ALC 50” for the
50 MHz amateur band's ALC Adjustment.
Alignment
Set the VFO-A frequency to 51.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "33".
Release the PTT buon.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “144/430 MHz” ANT jack.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-06 I-ALC 144” for the
144 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 145.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "29".
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-07 I-ALC 430” for the
430 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 439.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob to set the parameter is "31".
Release the PTT button, then press and hold
in the [MENU(SETUP)] buon for one second
to save the new seing and exit the alignment
mode.
ALIGNMENT-17
FT-991 Technical Supplement
Alignment
If the Main Firmware version of your
transceiver is “V10-13 or later”.
Connect the Microphone to the front panel MIC
jack.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “HF/50 MHz” ANT jack.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-01 I-ALC 1.8” for the
1.8 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 1.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 100 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“10” in-crease.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-02 I-ALC HFL” for
the 7 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 7.10 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 100 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“10” in-crease.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-03 I-ALC HFM” for
the 14 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 14.20 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 100 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“10” in-crease.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-04 I-ALC HFH” for
the 21 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 21.240 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 100 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“10” in-crease.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-05 I-ALC 50” for the
50 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 51.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 100 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“10” in-crease.
Connect the 50-Ohm Dummy Load and Watt-
meter to the “144/430 MHz” ANT jack.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-06 I-ALC 144” for the
144 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 145.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 50 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“5” in-crease.
Rotate the [MULTI] Dial knob to select the
alignment menu item “10-07 I-ALC 430” for the
430 MHz amateur band's ALC Adjustment.
Set the VFO-A frequency to 439.90 MHz in the
CW mode.
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 50 W on the Wameter.
Release the PTT buon, then rotate the [CLAR/
VFO-B] knob so that the parameter indication
“5” in-crease.
Press and hold in the [MENU(SETUP)] buon
for one second to save the new seing and exit
the alignment mode.
ALIGNMENT-18
FT-991 Technical Supplement
ALC Meter Adjustment
Connect the Microphone to the front panel MIC
jack.
Connect the 50-Ohm Dummy Load and
Wameter to the “HF/50 MHz” ANT jack.
Set the VFO-A frequency to 14.20 MHz in the
CW mode.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “13-03 100W TXG HFM”.
Rotate the [CLAR/VFO-B] knob to set the
parameter is "255".
Rotate the [MULTI] Dial knob to select the
alignment menu item “18-01 TX CAR USB”.
Rotate the [CLAR/VFO-B] knob to set the
parameter is "255".
Rotate the [MULTI] Dial knob to select the
alignment menu item “13-01 100W FALC
HFM”.
Rotate the [CLAR/VFO-B] knob to set the
parameter is "0".
Press the PTT button, then adjust the [CLAR/
VFO-B] knob for 100 W ±2.5 W on the Wameter.
Release the PTT button, then press and hold
in the [MENU(SETUP)] buon for one second
to save the new seing and exit the alignment
mode.
Set the USB mode.
Set the MIC GAIN to "50".
Connect the Audio Generator to pin 8 of the
MIC jack (pin 7: GND).
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item “20-01 ALC-MTR”.
Press the PTT button, then adjust the Audio
Generator output level to the position where RF
Power output to 88 - 92 W on the Wameter.
Release the PTT buon.
Increase the Audio Generator output level by
“+10 dB”.
Press the PTT buon, then press the [F(M-LIST)]
key while pressing and holding in the PTT
buon.
Release the PTT buon.
Alignment
Rotate the [CLAR/VFO-B] knob for maximum
deection on the ALC meter zone (S9 +10 dB),
then press the [F(M-LIST)] key, while pressing
and holding in the PTT buon.
Release the PTT button, then press and hold
in the [MENU(SETUP)] buon for one second
to save the new seing and exit the alignment
mode.
TX Output Power/PO Meter/TXG Adjustment
Referring to table below, tune the transceiver to
each frequency listed.
Band VFO-a Frequency MOde
1.8 MHz Band 1.90 MHz CW-USB
7 MHz Band 7.10 MHz CW-USB
14 MHz Band 14.20 MHz CW-USB
21 MHz Band 21.20 MHz CW-USB
50 MHz Band 51.90 MHz CW-USB
144 MHz Band 145.900 MHz CW-USB
430 MHz Band 439.900 MHz CW-USB
Connect the 50-Ohm Dummy Load and Watt-
meter to the “HF/50 MHz” and “144/430 MHz”
ANT jack.
Connect the Microphone to the front panel MIC
jack.
Press and hold in the [A=B], [A/B], and [FAST]
keys, while turning the radio on, to enter the
alignment mode.
Rotate the [MULTI] Dial knob to select the
alignment menu item to “11-01 100W FALC 1.8".
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob for 100 W ±3W on the
Wameter.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item to “11-02 MTR 1.8”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob for 100 W on the PO meter.
Release the PTT buon.
Rotate the [MULTI] Dial knob to select the
alignment menu item to “11-03 TXG 1.8”.
Press and hold the PTT buon, then rotate the
[CLAR/VFO-B] knob for "S9+10dB" on the ALC
meter zone.
Release the PTT buon.
Perform the same procedures for the Alignment
Menu Items “11-04 50W FALC 1.8” through
“11-15 5W TXG 1.8” per the chart at the below.
ALIGNMENT-19
FT-991 Technical Supplement
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