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7

FT-277R Technical Supplement

Circuit Description

Receive Signal Path

Incoming RF signal is from the antenna jack is delivered
to the Main Unit and passed through the low-pass filter
network, antenna switching diode 

D1003

 and 

D1004

(both 

RLS135

), and low-pass filter network to the RF

amplifier 

Q1022

 (

3SK296ZQ

). The amplified RF signal is

passed through band-pass filtered again by varactor-
tuned band-pass filter consisting of coils L1024, L1025,
and L1026, and diodes 

D1017

D1018

, and 

D1019

 (all

HVC350B

), then applied to the 1st mixer 

Q1023

(

3SK296ZQ

) along with the first local signal from the PLL

circuit.

The first local signal is generated between 382.75 MHz
and 402.75 MHz by the VCO, which consists of 

Q1014

(

2SC5006

)

 

and varactor diodes 

D1009

 (

HVC350B

), 

D1010

(

HVC375B

) and 

D1011

 (

HSC277

) according to the receiv-

ing frequency.

IF and Audio Circuits

The 47.25 MHz first IF signal is applied to the monolithic
crystal filter 

XF1001

 which strip away unwanted mixer

products, and the IF signal is applied to the first IF ampli-
fier 

Q1024

 (

2SC4915

). The amplified first IF signal is then

delivered to the FM IF subsystem IC 

Q1004

 (

NJM2591V

),

which contains the second mixer, limiter amplifier, noise
amplifier, and FM detector.

The 46.8 MHz second local signal which is made from
quadrupled 11.7 MHz crystal 

X1002

 produces the 450 kHz

second IF signal when mixed with first IF signal within

Q1004

 (

NJM2591V

).

The 450 kHz second IF signal is applied to the ceramic
filter 

CF1002

 which strip away unwanted mixer prod-

ucts to the ceramic discriminator 

CD1001

 which removes

any amplitude variations in the 450 kHz IF signal before
detection of speech.

The detected audio from the 

Q1004

 (

NJM2591V

) is ap-

plied to a band-pass filter consisting of 

Q1081

 and 

Q1082

(both 

2SC4617

), then passes through the audio mute gate

Q1052

 (

2SC4617

) and 

Q1045

 (

DTC144EE

).

The audio signal is passed through the audio VR which
adjusts the audio sensitivity to compensate for audio level
variations, then delivered to the audio amplifier 

Q1008

(

TDA2822D

).

Squelch Control

When no carrier received, noise at the output of the de-
tector stage in 

Q1004

 (

NJM2591V

) is applied to pin 49 of

main CPU 

Q1001

 (

HD64F2266TF13

), which compares the

squelch threshold level to that which set by the 

SQL

 knob.

While no carrier is received, pin 71 of 

Q1001

(

HD64F2266TF13

) remains “low,” to disable audio out-

put from the speaker.

Transmit Signal Path

The speech signal from the microphone is amplified by

Q1074

 (

LM2902PWR

). The amplified speech signal is sub-

jected to the low-pass filter network 

Q1074

 (

LM2902PWR

)

and deviation controller 

Q1075

 (

DTC144EE

).

UHF Transmit Signal Path

The adjusted speech signal from 

Q1075

 (

DTC144EE

) is

delivered to VCO 

Q1014

 (

2SC5006

) which frequency

modulates the transmitting VCO made up of 

D1010

(

HVC375B

).

The modulated transmit signal passes through buffer
amplifier 

Q1013

 and 

Q1012

 (both

 2SC5006

).

The transmit signal applied to the Pre-Drive amplifier

Q1011

 (

2SC5006

) and Drive amplifier 

Q1010

 (

2SK2596

),

then finally amplified by Power amplifier 

Q1009

(

2SK3476

) up to 5 Watts. This two stages (

Q1010

 and

Q1009

) power amplifier’s gain is controlled by the APC

circuit.

The 5 Watts RF signal passes through low-pass filter net-
work, antenna switch 

D1003

 (

RLS135

), and another low-

pass filter network, and then deliver to the 

ANT

 jack.

TX APC Circuit

A portion of the Power amplifier output is rectified by

D1002

 and 

D1052

 (both

 RB751S

), then delivered to APC

Q1019

  (

L M 2 9 0 4 P W R

), 

Q1020

 and 

Q1021

 (both

DTC144EE

), as a DC voltage which is proportional to the

output level of the power amplifier.

The APC 

Q1019

 (

LM2904PWR

) is compared the rectified

DC voltage from the power amplifier and the reference
voltage from the main CPU 

Q1001

 (

HD64F2266TF13

), to

produce a control voltage, which regulates supply volt-
age to the Drive amplifier 

Q1010

 (

2SK2596

) and Power

amplifier 

Q1009

 (

2SK3476

), so as to maintain stable out-

put power under varying antenna loading condition.

PLL

A portion of the output from the VCO 

Q1014

 (

2SC5006

),

passes through the buffer amplifier 

Q1017

 (

2SC5006

), then

delivered to the programmable divider section of the PLL
IC 

Q1003

 (

MB15A01PFV1

), which divided according to the

frequency dividing data that is associated with the setting
f r e q u e n c y   i n p u t   f r o m   t h e   m a i n   C P U  

Q 1 0 0 1

(

HD64F2266TF13

). It is then sent to the phase comparator.

The 11.7 MHz frequency of the reference oscillator circuit
made up of 

X1002

 is divided by the reference frequency

divider section of 

Q1003

 (

MB15A01PFV1

) into 2340 or

Summary of Contents for FT-277R

Page 1: ...olytic capacitors ICs etc or leaded components only While we believe the information in this manual to be correct VERTEX STANDARD 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 FT 277R VERTEX STANDARD CO LTD 4 8 8 Nakamegur...

Page 2: ...mm W O knob antenna belt clip Weight 13 8 Oz 390 g with FNB 83 antenna and belt clip Transmitter RF Power Output 5 0 W High 2 0 W Middle 0 5 W Low 7 2 V Modulation Type Variable Reactance F2D F3E Maximum Deviation 5 0 kHz F2D F3E Spurious Emission 60 dB or better High and Middle power 40 dB or better Low power Microphone Impedance 2 kΩ Receiver ircuit Type Double Conversion Superheterodyne Interme...

Page 3: ... SHEET RA0578300 WASHER RA057840A RING NUT RA057730B x2 pcs SPACER RA0577400 x2 pcs TERMINAL RA1203900 WINDOW FT 277R RA057710A HOLDER RA057700A RUBBER KNOB RA111430A DOUBLE FACE RA0434100 SHEET M4090185A SPEAKER RA0607200 SHEET PORON MAIN Unit RA1084700 O RING RA057720B LIGHT GUIDE RA1113200 PANEL FT 277R RA0557900 SP NET RA0748900 O RING RA1063700 SPACER Ref VXSTD P N U9900068 U9900181 U24110002...

Page 4: ...4 FT 277R Technical Supplement Exploded View Miscellaneous Parts Note ...

Page 5: ...5 Block Diagram FT 277R Technical Supplement ...

Page 6: ...6 Block Diagram FT 277R Technical Supplement Note ...

Page 7: ...plied to pin 49 of main CPU Q1001 HD64F2266TF13 which compares the squelch threshold level to that which set by the SQL knob While no carrier is received pin 71 of Q1001 HD64F2266TF13 remains low to disable audio out put from the speaker Transmit Signal Path The speech signal from the microphone is amplified by Q1074 LM2902PWR The amplified speech signal is sub jected to the low pass filter networ...

Page 8: ...hase comparator section of Q1003 MB15A01PFV1 compares the phase between the frequency divided os cillation frequency of the VCO circuit and comparative frequency and its output is a pulse corresponding to the phase difference This pulse is integrated by the charge pump and loop filter of D1012 DA221 into a control volt age VCV to control the oscillation frequency of the VCO ...

Page 9: ...lignment determined to be abso lutely necessary Required Test Equipment The following test equipment and familiarity with its use is necessary for complete realignment Correction of problems caused by misalignment resulting from use of improper test equipment is not covered under the war ranty policy While most steps do not require all of the equipment listed the interactions of some adjustments m...

Page 10: ...adio on Once the radio is on release these two switches 7 Press the keypad in the following sequence MHz 0 SET 2 CODE 2 CODE MR MW SKIP 8 Press the F key to cause A0 REF xxx to appear on the display for five seconds this signifies that the trans ceiver is now in the Alignment Mode PLL Reference Frequency 1 Rotate the DIAL knob to select the display to B0106 Press the F key then press the MR MW SKI...

Page 11: ... W key to recall the alignment parameter A2 PWR xxx 6 With in five second of appearing the A2 PWR xxx on the display press the PTT switch to activate the transmitter adjust the DIAL knob so that the watt meter reading is 2 0 Watts 0 1 Watt 7 Increase the Transmit power level to HIGH 8 Press the F W key to recall the alignment parameter A2 PWR xxx 9 With in five second of appearing the A2 PWR xxx o...

Page 12: ...nt parameter to A6 SM U D 7 With in five second of appearing the A6 SM U D on the display press the MHz key Squelch Sensitivity 1 Rotate the DIAL knob to select the display to B0206 2 Inject a 440 000 MHz signal at a level of 12 dBµV with 1 kHz modulation 3 5 kHz deviation from the RF signal generator 3 Press the F W key then press the MR MW SKIP key to set the alignment parameter to A7 SQL U D 4 ...

Page 13: ... 1 95 V 1 95 V 5 13 V 1 48 V CHG PWR OFF 0 91 V CHG PWR OFF 1 53 V CHG 13 1 V CHG 13 8 V 13 5 V 4 90 V 4 86V 0 99V 16 4dBµ 4 21V 2 24V 0 71V 4 68V 1 79V 0 4V 0 99V TX 1 88 V TX 2 62V TX H 2 10V TX M 1 60V TX L 1 10V TX H 7 85V TX M 7 90V TX L 7 92V TX H 2 21V TX M 1 28V TX L 0 49V TX H 1 95V TX M 1 15V TX L 0 46V TX 1 72 V 4 83V 4 30V 2 84V 0 89V 0 25V 2 10 V 2 10 V 2 10 V TUNE2 06V 5 13 V 1 95 V ...

Page 14: ...14 MAIN Unit FT 277R Technical Supplement Note ...

Page 15: ... GR RTK P Q1030 1031 1032 1034 1040 1059 KTC4075E GR RTK P Q1035 1038 1039 1042 1061 1062 1064 1065 1069 1076 1077 1079 2SC4915 QY Q1024 FMMTL718TA Q1041 2SB1132 BA Q1063 1078 KRA304E RTK P Q1033 1043 1058 1071 KRC404E RTK P Q1020 1021 1029 1044 1045 1057 1068 2SB1201S Q1037 2SD1664 DA Q1067 2SK3476 Q1009 BR24L64F Q1002 LM2904PWR Q1019 TDA2822 Q1008 ...

Page 16: ...0 1066 1072 1073 1081 1082 2SC4915 QY Q1016 2SC5006 73 Q1011 1012 1013 1014 1017 KRC404E RTK P Q1015 1025 1026 1047 1048 1049 1051 1070 1075 MB15A01PFV1 Q1003 NJM2591V Q1004 DA221 K D1012 1030 DAN222 N D1029 2SJ364 4M Q1056 2SK2596 BX Q1010 KRA304E RTK P Q1027 1054 1084 LM2904PWR Q1083 LM2902PWR Q1046 1074 NJU7231F33 Q1007 XC6202P Q1080 BU2090FS Q1005 3SK296ZQ ZQ Q1022 1023 ...

Page 17: ...6R0BZ01D K22178293 1 B b1 C 1039 CHIPCAP 8pF 50V CH GRM1552C1H8R0BZ01D K22178295 1 B b1 C 1040 CHIPCAP 0 001uF 50V B GRM155B11H102KA01D K22178809 1 B c1 C 1041 CHIPCAP 0 01uF 16V B GRM36B103K16PT K22128804 1 B c1 C 1041 CHIPCAP 0 01uF 25V B GRM155B11E103KA01D K22148834 11 B c1 C 1042 CHIPCAP 0 001uF 50V B GRM155B11H102KA01D K22178809 1 B c1 C 1043 CHIPCAP 13pF 50V CH MCH155A130JK K22179706 1 B c1 ...

Page 18: ...8222 1 B b1 C 1115 CHIPCAP 27pF 50V CH GRM1552C1H270JZ01D K22178222 1 B c1 C 1116 CHIPCAP 0 75pF 50V CK GRM1554C1HR75BZ01D K22178286 1 B c1 C 1117 CHIPCAP 0 75pF 50V CK GRM1554C1HR75BZ01D K22178286 1 B c1 C 1119 CHIPCAP 27pF 50V CH GRM1552C1H270JZ01D K22178222 1 B c1 C 1121 CHIPCAP 8pF 50V CH GRM1552C1H8R0BZ01D K22178295 1 B c1 C 1122 CHIPCAP 0 001uF 50V B GRM155B11H102KA01D K22178809 1 B c1 C 112...

Page 19: ...HIPCAP 0 0047uF 25V B GRM36B472K25PT K22148830 1 A F2 C 1176 CHIPCAP 0 0047uF 50V B GRM155B11H472KA01D K22178838 11 A F2 C 1177 CHIPCAP 0 001uF 50V B GRM155B11H102KA01D K22178809 1 B b1 C 1178 CHIPCAP 0 1uF 10V B GRM155B11A104KA01D K22108802 1 B d3 C 1179 CHIPCAP 0 1uF 10V B GRM155B11A104KA01D K22108802 1 B e3 C 1180 CHIPCAP 0 01uF 16V B GRM36B103K16PT K22128804 1 B c3 C 1180 CHIPCAP 0 01uF 25V B ...

Page 20: ...28806 DST USA2 19 B b3 C 1237 CHIPCAP 470pF 50V B GRM155B11H471KA01D K22178805 1 18 B b3 C 1237 CHIPCAP 470pF 50V B GRM155B11H471KA01D K22178805 DST EXP2 19 B b3 C 1237 CHIPCAP 470pF 50V B GRM155B11H471KA01D K22178805 DST USA2 19 B b3 C 1238 CHIPCAP 0 001uF 50V B GRM155B11H102KA01D K22178809 1 A E2 C 1239 CHIPCAP 0 001uF 50V B GRM155B11H102KA01D K22178809 1 3 A D1 C 1239 CHIPCAP 0 001uF 50V B GRM1...

Page 21: ...4 DIODE RLS135 TE 11 G2070128 1 B a1 D 1007 DIODE 1SS400 TE61 G2070634 1 B d1 D 1008 DIODE 1SS400 TE61 G2070634 1 B d1 D 1009 DIODE HVC350B TRF E G2070596 1 B e1 D 1010 DIODE HVC375B TRF E G2070856 1 B e1 D 1011 DIODE HSC277TRF E G2070584 1 B e1 D 1012 DIODE DA221 TL G2070178 1 B e1 D 1013 DIODE 1SS400 TE61 G2070634 1 B f1 D 1014 DIODE HVC350B TRF E G2070596 1 B f1 D 1015 DIODE HVC365 TRF E G20709...

Page 22: ...RFC 0 01uH 2 C1608CB 10NG RF L1691032 1 B a1 L 1021 M RFC 0 01uH 2 C1608CB 10NG RF L1691032 1 B b2 L 1022 M RFC 0 039uH 2 C1608CB 39NG RF L1691039 1 B b2 L 1023 M RFC 0 1uH TFL0816 100N L1690981 1 B b1 L 1024 M RFC 0 01uH 2 C1608CB 10NG RF L1691032 1 B b1 L 1025 COIL E2 0 28 1 0 4T R L0022365 1 B c1 L 1026 COIL E2 0 28 1 0 4T R L0022365 1 B c1 L 1027 M RFC 0 39uH 2 C1608CB R39G RF L1691107 1 B c1 ...

Page 23: ...E2 Q 1038 TRANSISTOR KTC4075E GR RTK P G3070356 6 A E2 Q 1039 TRANSISTOR 2SC4617 TL R G3346178R 1 A E1 Q 1039 TRANSISTOR KTC4075E GR RTK P G3070356 6 A E1 Q 1040 TRANSISTOR 2SA1774 TL R G3117748R 1 A E2 Q 1040 TRANSISTOR KTA2014E GR RTK P G3070353 6 A E2 Q 1041 TRANSISTOR FMMTL718TA G3070335 1 A E2 Q 1042 TRANSISTOR 2SC4617 TL R G3346178R 1 A E2 Q 1042 TRANSISTOR KTC4075E GR RTK P G3070356 6 A E2 ...

Page 24: ...56 6 B e3 Q 1083 IC LM2904PWR G1094010 1 B c2 Q 1084 TRANSISTOR DTA144EE TL G3070074 1 B c3 Q 1084 TRANSISTOR KRA304E RTK P G3070354 6 B c3 R 1001 CHIPRES 10k 1 16W 5 RMC1 16S 103JTH J24189037 1 A E1 R 1002 CHIPRES 10k 1 16W 5 RMC1 16S 103JTH J24189037 1 A E1 R 1003 CHIPRES 3 3k 1 16W 5 RMC1 16S 332JTH J24189031 1 A E1 R 1004 CHIPRES 33k 1 16W 5 RMC1 16S 333JTH J24189043 1 A E1 R 1005 CHIPRES 330 ...

Page 25: ...89057 1 B f1 R 1067 CHIPRES 820k 1 16W 5 RMC1 16S 824JTH J24189060 1 B f1 R 1068 CHIPRES 470k 1 16W 5 RMC1 16S 474JTH J24189057 1 B f1 R 1069 CHIPRES 68k 1 16W 5 RMC1 16S 683JTH J24189047 1 B f1 R 1070 CHIPRES 330k 1 16W 0 5 MCR01MZPD3303 J24189330 1 B f1 R 1071 CHIPRES 330k 1 16W 0 5 MCR01MZPD3303 J24189330 1 B f1 R 1072 CHIPRES 470k 1 16W 5 RMC1 16S 474JTH J24189057 1 A E1 R 1073 CHIPRES 100k 1 ...

Page 26: ...TH J24189049 1 A F3 R 1147 CHIPRES 100 1 16W 5 RMC1 16S 101JTH J24189013 1 A F2 R 1148 CHIPRES 100k 1 16W 5 RMC1 16S 104JTH J24189049 1 A E1 R 1149 CHIPRES 4 7 1 16W 5 RMC1 16S 4R7JTH J24189066 1 A E2 R 1150 CHIPRES 4 7 1 16W 5 RMC1 16S 4R7JTH J24189066 1 A E2 R 1151 CHIPRES 15k 1 16W 5 RMC1 16S 153JTH J24189039 1 A E3 R 1152 CHIPRES 100 1 16W 5 RMC1 16S 101JTH J24189013 1 A E2 R 1153 CHIPRES 15k ...

Page 27: ...9 1 A E3 R 1220 CHIPRES 2 2k 1 16W 5 RMC1 16S 222JTH J24189029 1 A F3 R 1221 CHIPRES 100 1 16W 5 RMC1 16S 101JTH J24189013 1 A F3 R 1222 CHIPRES 2 2k 1 16W 5 RMC1 16S 222JTH J24189029 1 B b2 R 1223 CHIPRES 1M 1 16W 5 RMC1 16S 105JTH J24189061 1 B b2 R 1224 CHIPRES 1 2M 1 16W 5 RMC1 16S 125JTH J24189062 1 B b2 R 1225 CHIPRES 10k 1 16W 5 RMC1 16S 103JTH J24189037 1 B b2 R 1226 CHIPRES 2 2M 1 16W 5 R...

Page 28: ...71JTH J24189021 1 A E2 R 1299 CHIPRES 220 1 16W 5 RMC1 16S 221JTH J24189017 1 B f2 R 1300 CHIPRES 220 1 16W 5 RMC1 16S 221JTH J24189017 1 A A3 R 1301 CHIPRES 220 1 16W 5 RMC1 16S 221JTH J24189017 1 A B1 R 1302 CHIPRES 330 1 16W 5 RMC1 16S 331JTH J24189019 1 A B1 R 1303 CHIPRES 150 1 16W 5 RMC1 16S 151JTH J24189015 1 A B1 R 1304 CHIPRES 100k 1 16W 0 5 RR0510R 104 D J24189167 1 A C1 R 1304 CHIPRES 1...

Page 29: ...2 CHIPRES 0 1 16W 5 RMC1 16SJPTH J24189070 1 B f2 R 1364 CHIPRES 10k 1 16W 5 RMC1 16S 103JTH J24189037 1 B c2 R 1365 CHIPRES 220 1 16W 5 RMC1 16S 221JTH J24189017 1 A E2 R 1366 CHIPRES 0 1 16W 5 RMC1 16SJPTH J24189070 1 B b2 R 1367 CHIPRES 470 1 16W 5 RMC1 16S 471JTH J24189021 1 A E1 R 1368 CHIPRES 470 1 16W 5 RMC1 16S 471JTH J24189021 1 A E1 R 1369 CHIPRES 82k 1 16W 5 RMC1 16S 823JTH J24189048 1 ...

Page 30: ...30 Parts List MAIN Unit REF DESCRIPTION VALUE V W TOL MFR S DESIG VXSTD P N VERS LOT SIDE LAY ADR FT 277R Technical Supplement Note ...

Page 31: ...31 FT 277R Technical Supplement FTD 7 DTMF Paging Unit Option Circuit Diagram Parts Layout DTA144EE 16 Q6002 6005 DTC144EE 26 Q6004 2SC4617 BR 6003 BU8872FS Q6001 Side A Side B ...

Page 32: ...1 CONNECTOR AXK5F14545YJ P1091240 1 Q 6001 IC BU8872FS E2 G1093656 1 Q 6002 TRANSISTOR DTA144EE TL G3070074 1 Q 6003 TRANSISTOR 2SC4617 TL R G3346178R 1 Q 6004 TRANSISTOR DTC144EE TL G3070075 1 Q 6005 TRANSISTOR DTA144EE TL G3070074 1 R 6001 CHIP RES 4 7k 1 16W 5 RMC1 16S 472JTH J24189033 1 R 6002 CHIP RES 47k 1 16W 5 RMC1 16S 473JTH J24189045 1 R 6003 CHIP RES 100k 1 16W 5 RMC1 16S 104JTH J241890...

Page 33: ......

Page 34: ...14 FT 277R Technical Supplement Copyright 2010 VERTEX STANDARD CO LTD All rights reserved No portion of this manual may be reproduced without the permission of VERTEX STANDARD CO LTD ...

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