Yaesu FT-991A Service Manual

Technical Supplement

HF/VHF/UHF ALL MODE TRANSCEIVER

FT-991

Introduction

This manual provides the technical information necessary for servicing the FT-991A HF/VHF/UHF ALL MODE TRANSCEIVER. Servicing this equipment requires expertise in hand- ing surface-mount chip components. Attempts by non-

qualied 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 double- sided 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.

EH067M90B

Specications

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 TUNER Unit JACK Unit SCP Unit DSP Unit

Important Note

This transceiver was assembled using Pb (lead) free solder, based on the RoHS specication.

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 specication, and any solder with the above alloy com- position may be used.

Caution

Risk of explosion if battery is replaced by an incorrect type. Dispose of used batteries according to the instructions.

Specications

General

Rx Frequency Range: 30 kHz - 56 MHz, 118 MHz - 164 MHz, 420 MHz - 470 MHz (operating)

1.8 MHz - 54 MHz, 144 MHz - 148 MHz, 430 MHz - 450 MHz (specied performance, Amateur bands only)

Tx Frequency Ranges: 1.8 MHz - 54 MHz, 144 MHz - 148 MHz, 430 MHz - 450 MHz (Amateur

bands only)

Frequency Stability: ±0.5 ppm (after 1 minute @+14 °F to +122 °F [–10 °C to +50 °C]) Operating Temperature Range: +14 °F to +122 °F (–10 °C to +50 °C) Emission Modes: A1A (CW), A3E (AM), J3E (LSB, USB), F3E (FM), F7W (C4FM), F2D Frequency Steps: 5/10 Hz (SSB, CW, & AM), 100 Hz (FM, C4FM) Antenna Impedance: 50 Ohms, unbalanced

16.7 - 150 Ohms, unbalanced (Tuner ON, 1.8 MHz - 30 MHz Amateur bands) 25 - 100 Ohms, unbalanced (Tuner ON, 50 MHz Amateur band) Power Consumption (Approx.): Rx (no signal) 1.8 A Rx (signal present) 2.2 A Tx 23 A (HF/50 MHz 100 W)

15 A (144/430 MHz 50 W)

Supply Voltage: DC 13.8 V ± 15% (Negative Ground) Dimensions (WxHxD): 9.0” x 3.2” x 10.0” (229 x 80 x 253 mm) Weight (Approx.): 9.5 lbs (4.3 kg)

Transmier

Power Output: 5 - 100 was (2 - 25 was AM carrier) Modulation Types: J3E (SSB): Balanced,

A3E (AM): Low-Level (Early Stage), F3E (FM): Variable Reactance F7W (C4FM): 4-level FSK

Maximum FM Deviation: ±5.0 kHz/±2.5 kHz Harmonic Radiation: Beer than –50 dB (1.8 MHz - 30 MHz Amateur bands)

Beer than –63 dB (30 MHz Amateur band) Beer than –60 dB (144 MHz, 430 MHz Amateur bands)

SSB Carrier Suppression: At least 50 dB below peak output Undesired Sideband Suppression: At least 50 dB below peak output Bandwidth: 3 kHz (LSB/USB), 500 Hz (CW), 6 kHz (AM), 16 kHz (FM/C4FM) Audio Response (SSB): Not more than –6 dB from 300 to 2700 Hz Microphone Impedance: 600 Ohms (200 to 10 kOhms)

SPECIFICATIONS-1

FT-991 Technical Supplement

Specications

Receiver

Circuit Type: SSB/CW/AM: Triple-conversion Superheterodyne

FM/C4FM: Double-conversion Superheterodyne Intermediate Frequencies: 40.455 MHz SSB/CW/AM: 69.450 MHz/9.000 MHz/24 kHz FM/C4FM: 69.450 MHz/450 kHz

Sensitivity: SSB/CW (BW: 2.4 kHz, 10 dB S+N/N)

0.158 µV (1.8 - 30 MHz) (AMP 2 “ON”)

0.125 µV (50 - 54 MHz) (AMP 2 “ON”)

0.11 µV (144 - 148 MHz)

0.11 µV (430 - 450 MHz)

AM (BW: 6 kHz, 10 dB S+N/N, 30 % modulation @400 Hz) 5 µV (0.5 - 1.8 MHz) (AMP 2 “ON”)

1.6 µV (1.8 - 30 MHz) (AMP 2 “ON”)

1.25 µV (50 - 54 MHz) (AMP 2 “ON”) FM (BW: 15 kHz, 12 dB SINAD)

0.35 µV (28 - 30 MHz) (AMP 2 “ON”)

0.35 µV (50 - 54 MHz) (AMP 2 “ON”)

0.18 µV (144 - 148 MHz)

0.18 µV (430 - 440 MHz)

There is no specication for frequency ranges not listed.

Squelch Sensitivity (TYP.): SSB/CW/AM

1.0 µV (1.8 - 30 MHz, 50 - 54 MHz) (AMP 2 “ON”)

1.0 µV (144 - 148 MHz, 430 - 450 MHz) FM

0.35 µV (28 - 30 MHz, 50 - 54 MHz) (AMP 2 “ON”)

0.125 µV (144 - 148 MHz, 430 - 450 MHz)

There is no specication for frequency ranges not listed. Selectivity: Mode –6 dB –60 dB CW/RTTY/PKT 0.5 kHz or beer 750 Hz or less SSB 2.4 kHz or beer 3.6 kHz or less AM 6 kHz or beer 15 kHz or less FM 12 kHz or beer 30 kHz or less (–50 dB) Image Rejection: 70 dB or beer (1.8 MHz - 50 MHz Amateur bands) 60 dB or beer (144/430 MHz Amateur band)

Maximum Audio Output: 2.5 W into 4 Ohms with 10% THD Audio Output Impedance: 4 to 8 Ohms (4 Ohms: nominal) Conducted Radiation: Less than 4 nW

Specications 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

R7153663 HIMERON

①

RA600120A TOP CASE

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

②

③

RA6046900 BLIND SHEET (0715)

RA089840A SP NET

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

RA6024400 PORON SHEET(6x25)

①

RA0423200 LOCK PLATE

RA089560A GASKETW9H4L40

①

RA1236600 PORON SHEET(10X10t3)

RA6101700 GASKET(70x40)

③

RA6000800 SHIELD CASE COVER

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

JACK-UNIT

①

RA6035100 LEAF SPRING

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)

RA6107900 FRONT PANEL(PRT)

RA6025300 BLIND SHEET(9x28)

J60800322 POT (w/ ø1, ø2)

RA1528400 WASHER(PE)

RA6004500 RUBBER RING(MAIN)

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

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

RA600030A CHASSIS

RA6000900 SHIELD CASE COVER

RA1499500 PORON SHEET(25x35)

RA1559100 GASKET(5x12) (3 pcs)

①

②

③

CNTL-UNIT

②

①

②

RA1391800 SPACER(DSP)

DSP-UNIT

②

RA6015300 GASKET(120x10)

RA602550A PORON SHEET (10x85)

RA0060200 SHIELD CASE

RA1558800 GASKET(60x12)

②

EDSP-UNIT

②

①

RA6001000 RUBBER PACKING

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

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

③

①

③

④

①

R0131670A SHIELD CASE

①

③

①

RA6032400 Thermal Conductive Pad

①

RA6049000 Thermal Conductive Pad

①

V_U-PA-UNIT

M2090052 FAN

⑥

P1091158A CONNECTOR

S5000320 FAN GUARD

⑥

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

RA6108900 GASKET

RA6115000 GASKET

②

⑤

RA0830400 SHIELD CASE COVER

④

SCP-UNIT

④

②

⑤

RA6110000 SHIELD CASE(21X25.5)

RA0830300 SHIELD CASE(21X25)

MAIN-UNIT

②

RA6032400 Thermal Conductive Pad

S5000260 LEAD CLAMP CC-1002

②

RA1152200 SHIELD CASE(28x15)

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 9

②

U24306001 BIND HEAD TAPTITE-B M3X6 5

③

U20205001 BINDING HEAD SCREW M2.6X5 3

④

S5000414 SPACER QBSB2613E 3

⑤

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

Realignment may be required after the components have been replaced.

We recommend that authorized Yaesu Technicians, who are experienced with the circuitry and fully equipped to align our products, perform aligns.

Those who do undertake any of the following alignments are cautioned to proceed at their own

risk. Problems caused by unauthorized aempts at

realignment are not covered by the warranty poli- cy.

The need for realignment should be determined to be absolutely necessary.

The following test equipment (and a thorough fa- miliarity with its correct use) is necessary for cor- rect realignment. Most steps do not require all of the equipment listed. The interactions of some ad- justments may require that more complex adjust-

ments be performed in a sequence. Do not aempt

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.

Alignment Preparation & Precautions

A 50-ohm RF Dummy load and in-line wameter

must be connected to the ANT jack in all proce- dures that call for transmission, except where spec- ified otherwise. Correct alignment is not possible with an antenna.

After 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 wameter).

Correct alignment requires that the ambient tem- perature 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 tempera- ture 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 af- xed in place.

Note: Signal levels in dB referred to in this proce-

dure are based on 0 dBµ = 0.5 µV (closed cir- cuit).

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 was)



In-Line Wameter (150/300 was, 50-Ohm)



Linear Detector



RF Coupler



4-Ohm AF Dummy Load (3 was)



1/4-inch 3-contact Plug



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 the [F(M-LIST)] key.



Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing 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 deects to full scale.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seings 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 ap-



propriate “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 Conrm At least 0.3 V At least 3 dBm

01-07 VCO2-HIGH

01-08 VCO2-LOW Conrm At least 0.6 V At least 3 dBm

01-09 VCO3-HIGH

01-10 VCO3-LOW Conrm At least 0.4 V At least 3 dBm

01-11 VCO4-HIGH

01-12 VCO4-LOW Conrm At least 0.5 V At least 3 dBm

01-13 VCO5-HIGH

01-14 VCO5-LOW Conrm At least 0.8 V At least 3 dBm

Disconnect the RF millivoltmeter from J2001,



Adjust /

Conrm

Adjust L2004

Adjust L2005

Adjust L2006

Adjust

TC2001

Adjust

TC2002

DC voltmeter RF millivoltmeter

5.1 V ±0.1 V At least 3 dBm

4.1 V ±0.1 V At least 3 dBm

5.0 V ±0.1 V At least 3 dBm

then re-connect the coaxial cable to J2001.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing 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



deection on the RF millivoltmeter.

Local Level Adjustment

2nd

Connect the RF millivoltmeter to TP1025 on the



MAIN Unit.

Adjust T1027, T1028, T1030, and T1033 on the



MAIN Unit for maximum deection 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)] buon



for one second to save the new seing 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 buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+10 dBm ±1 dBm”.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item “02-02 Local HFL”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+10 dBm ±1 dBm”.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item “02-03 Local HFM”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+10 dBm ±1 dBm”.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item “02-04 Local HFH”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+10 dBm ±1 dBm”.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item “02-05 Local 50”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+11.5 dBm ±0.5 dBm”.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item “02-06 Local 144”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+10 dBm ±1 dBm”.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item “02-07 Local 430”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob so that the RF millivolt- meter reading is “+10 dBm ±1 dBm”.

Release the PTT buon.



Alignment

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seings 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

TP1005

ALIGNMENT-6 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 deection 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 deect.

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 devia- tion 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

deection 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 deect.

T1001

T1003

TC1001

TC1007

T1025

T1026

ALIGNMENT-7 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 +70 dBµ at the 69.450000 MHz.

Adjust T1017 on the MAIN Unit for minimum



deection 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 deect.

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 Align- ment 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)] buon



for one second to save the new seing 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 be- low, then set the RF Signal Generator output to each frequency & level, and adjust the [CLAR/ VFO-B] knob for the corresponding AF milli- voltmeter reading at each frequency.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seings and exit

the alignment mode.

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

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)

0 dB

ALIGNMENT-9 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 seing 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)] buon



for one second to save the new seings 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 devia- tion 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



seing.

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



seing.

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)] buon



for one second to save the new seing 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)] buon



for one second to save the new seings 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 devia- tion 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



seing.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing 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 devia- tion 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



seing.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing 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 devia- tion 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



seing.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing 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 with ±3.5 kHz de- viation 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.

Set the RF Signal Generator to 145.897 MHz.



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



seing.

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



seing.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing and exit

the alignment mode.

ALIGNMENT-11 FT-991 Technical Supplement

Alignment

Scope Adjustment

Set the VFO-A frequency to 14.200 MHz in the



CW 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.

Connect the RF millivoltmeter to TP6501 on the



SCP Unit.

Adjust T6507, T6506 and T6504 on the SCP



Unit in succession several times for maximum

deection on the RF millivoltmeter.

Set the RF Signal Generator output level to +36



dBµ at the 14.200 MHz.

Press the assigned [A], [B] or [C] key to activate



the SCOPE function.

Adjust T6501 on the SCP Unit for maximum



deection on the SCOPE display.

Turn the RF Signal Generator OFF.



As shown in the gure below, adjust VR6501 so



the waveform matches the second line from the top on the scope display.

T6506

TP6501

T6504

VR6501

T6507

ALIGNMENT-12 FT-991 Technical Supplement

Transmier 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 buon.



Set the VFO-A frequency to 145.900 MHz in the



FM mode.

Press the PTT buon, adjust T1008, T1007 and



T1006 for maximum deection on the RF milli- voltmeter.

Alignment

Release the PTT buon.



Set the VFO-A frequency to 439.900 MHz in the



FM mode.

Press the PTT button, adjust TC1004, TC1003



and TC1002 for maximum deection on the RF

millivoltmeter.

Release the PTT buon.



Disconnect the RF millivoltmeter from J1004 on



the MAIN Unit, then connect the Spectrum An- alyzer to J1004.

Set the VFO-A frequency to 52.000 MHz in the



CW-USB mode.

Press the PTT buon, adjust T1005 on the spu-



rious (69.450 MHz) for minimum deection on

the Spectrum Analyzer.

Release the PTT buon.



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-13 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 buon.



Disconnect the DC ammeter from J4505.



J4507 J4503

J4505 VR4501J4506

ALIGNMENT-14 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 buon.



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 buon.



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 buon.



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 5 of the



MIC jack (pin 4: GND), then set the output level to 0.5 mV @1 kHz.

Press the PTT buon, then adjust the MIC gain



to set the RF Power output to 25 W on the Wa- meter.

Press the PTT buon, adjust TC4501 for maxi-



mum deection on the Wameter.

Release the PTT buon.



J4501J4502

J4507 J4503VR4505

VR4502 VR4506J4506

J4505 TC4501

VR4503

ALIGNMENT-15 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 50- Ohm 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)”.

Release the PTT buon.



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)”.

Release the PTT buon.



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.

J4006 J4007J4004 VR4001J4001 J4005VR4002

ALIGNMENT-16 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 buon, then adjust the MIC gain



to set the RF Power output to 50 W on the Wa- meter.

Press the PTT buon, adjust TC4001 for mini-



mum deection on the DC voltmeter (less than

0.1 V).

Release the PTT buon.



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 buon, then adjust the MIC gain



to set the RF Power output to 25 W on the Wa- meter.

Press the PTT buon, adjust VR4507 for mini-



mum deection on the DC voltmeter (less than

0.3 V).

Release the PTT buon.



TC4001J4013

VR4507

ALIGNMENT-17 FT-991 Technical Supplement

Current ALC Adjustment

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 Wameter.

Release the PTT buon, 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 for 100 W on the Wameter.

Release the PTT buon, 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 “10-03 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 Wameter.

Release the PTT buon, 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 “10-04 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 Wameter.

Release the PTT buon, then rotate the [CLAR/



VFO-B] knob so that the parameter indication “10” in-crease.

Alignment

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 Wameter.

Release the PTT buon, then rotate the [CLAR/



VFO-B] knob so that the parameter indication “5” 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 100 W on the Wameter.

Release the PTT buon, 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 439.00 MHz in the



CW mode.

Press the PTT button, then adjust the [CLAR/



VFO-B] knob for 50 W on the Wameter.

Release the PTT buon, then rotate the [CLAR/



VFO-B] knob so that the parameter indication “3” in-crease.

Press and hold in the [MENU(SETUP)] buon



for one second to save the new seing and exit

the alignment mode.

ALIGNMENT-18 FT-991 Technical Supplement

Alignment

ALC Meter Adjustment

Connect the Microphone to the front panel MIC



jack.

Connect the 50-Ohm Dummy Load and



Wameter 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 Wameter.

Release the PTT buon.



Set the USB mode.



Set the MIC GAIN to "50".



Connect the Audio Generator to pin 5 of the



MIC jack (pin 4: GND).

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 Wameter.

Release the PTT buon.



Increase the Audio Generator output level by



“+10 dB”.

Press the PTT buon, then press the [F(M-LIST)]



key while pressing and holding in the PTT buon.

Release the PTT buon.



Rotate the [CLAR/VFO-B] knob for maximum



deection on the ALC meter zone (S9 +10 dB), then press the [F(M-LIST)] key, while pressing and holding in the PTT buon.

Release the PTT button, then press and hold



in the [MENU(SETUP)] buon for one second to save the new seing 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 buon, then rotate the



[CLAR/VFO-B] knob for 100 W ±3W on the Wameter.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item to “11-02 MTR 1.8”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob for 100 W on the PO me- ter.

Release the PTT buon.



Rotate the [MULTI] Dial knob to select the



alignment menu item to “11-03 TXG 1.8”.

Press and hold the PTT buon, then rotate the



[CLAR/VFO-B] knob for "S9+10dB" on the ALC meter zone.

Release the PTT buon.



ALIGNMENT-19 FT-991 Technical Supplement

+ 101 hidden pages

Yaesu FT-991A Service Manual

Introduction

Contents

General

Receiver

Exploded View

Block Diagram

Connection Diagram

Alignment

Alignment Preparation & Precautions

Required Test Equipment

VDD Meter Adjustment

COMP Meter Adjustment

VCO Adjustment

2nd/3rd Local Oscillator Adjustment

3rd Local Level Adjustment

Local Level Adjustment

REF OSC Adjustment

FM Local Oscillator Adjustment

1st Local Oscillator Adjustment

MCF Adjustment (1)

MCF Adjustment (2)

IF Trap Adjustment

RF AGC Adjustment

IF Gain Adjustment

S-meter Adjustment

S-meter Adjustment (FM)

FIL Gain Adjustment

FM Squelch Adjustment

FM Center Stop Adjustment

Scope Adjustment

TX IFT Adjustment

V-U PA Unit Adjustment

Preparation

Pre-Drive Stage Idling Current Adjustment

Drive Stage Idling Current Adjustment

Semi-Final Stage Idling Current Adjustment

Final Stage Idling Current Adjustment

V_U-PA Unit TX Adjustment

HF PA Unit Adjustment

Preparation

CM Coupler Balance Adjustment

Current ALC Adjustment

ALC Meter Adjustment