Kenwood TM-281A Service Manual Download Page 41

Page: 41 / 50

TM-281A

Q709

IC708

2SB1694

(NARROW)

IC715

MC2858-T111

8TC

AVR

49.95MHz

8RC

AMP

Q711

Q707

OVER

EX24064ASAS0A

Q710

MC2858-T111

ANT

BUFF

BSB

XF501

POWER

INT

RT1N141U-T111

Q10

D309,D311

JDP2S12CR

INT

Vgg

450kHz

BPF

LA4600

MCU

WIDE

ANT SW

LNA

VOLTAGE

(WIDE)

1SV325F

3SK294-FP

Q713

TX/RX

IC710

TA7808F-NQ

AVR

TEMP2

Q503

MIXER

Q504

VCO

2SC5108(Y)F

CF502

2SC5108(Y)F

IC711

8CL

1SV325F

D508,D509

TX/RX

IC302

2SB1694

50.4MHz

Q505

MUTE

Q501

XC6209B502P-G

TUNE

VCOMOD

IC713

NARROW

EEPROM

Q714

RESET

TA7805F-NQ

TUNE

30622MEP540GU

AVR

BPF

RT1N141U-T111

DTC363EU

XC61CN4002MR

RESET

XC61CN3202MR

QIN

RT1N141U-T111

Q708

MODULE

SBC

CF501

POWER

SPM

DRIVE

D313,D314

DEMODULATOR

AF AMP

D505,D506

IC707

MCF

INT

2SJ347F

D306,D307

L407CDB

D500

KTC4080E-P

TRIPPLER

APC

IC712

TEMP1

DETECT

RD00HVS1-T113

LPF

D502

Q303

1st Local
185.950~223.9475MHz
(K,M2,M3)
193.950~197.9475MHz
(M4)

oscillation frequency

371.900~447.895MHz (K,M2,M3)
387.900~395.895MHz (M4)
272.000~347.995MHz (M2,M3)
288.000~295.995MHz (K,M4)

RX: 136.000~173.9975MHz (K,M2,M3)
144.000~147.9975MHz

(M4)

TX: 136.000~173.9975MHz (M2,M3)
144.000~147.9975MHz

(K,M4)

RF BPF

Q712

HSC277

EXT

16.8MHz

3SK318

2SJ645

VCO

RF BPF

IC714

MCH3914(7)-H

EEPSDT

IC501

RT1N141U-T111

AMPSW

Q715

RSSI
SQIN

UA31136L

AMP

COMM

AMP

D9,D10

HSB88AS-E

DETECTOR

IC303
NJM12904RB1

AMP

RSSI

RT1N141U-T111

MCH3914(7)-H

RA60H1317M231

L71-0655-05

L72-1034-05

L72-0999-05

BSB

8.000MHz

L78-1427-05

X701

UDZW18(B)

D712

XIN

XOUT

FUSE

F701

F53-0327-15

NOISE

AMP

Q502

DETECTOR

D503

HSB88AS-E

NOISE

Q506

2SK1830F

TH702,TH703

NCP18WF104J03

UMC4N

DIVIDER

IC2

UPB1509GV

SPOUT

KTC4080E-P

W/NI

2SC4617(S)

M62363FP-F

IC705(1/8)

CONV.

D/A

W/NI

FILTER

IC709

BA10324AFV

HPF

Q706

2SC2412K

Q704,Q705

2SK3019

MUTE

AFM

DTMFIN

D/A

IC705(7/8,8/8)

CONV.

M62363FP-F

DTMF

SPGND

D/A

IC705(2/8)

CONV.

M62363FP-F

BA10324AFV

AMP

IC706(4/4)

BSHIFT

Q702,Q703
2SC4919-S

TEMP.

DETECTOR

TEMP1
TEMP2

TONE

DTMO

PLLE
EVLLD

BSHIFT

RESET
POWER

INT

TX/RX

EEPCK
EEPWP

TXD

PTT
RXD

SPM
AMPSW

DT
CK

NARROW
WIDE

DO
CE
CL

ENCB

ENCA

MICMT

8RC

8TC

SBC

MICKEY

VOL

DTMFIN

2nd_Local

BLOCK DIAGRAM

Summary of Contents for TM-281A

Page 1: ...K29 9497 01 Modular jack MIC E58 0535 05 Panel assy A62 1187 13 Knob VOL K29 9498 03 Knob ENC K29 9499 03 DISASSEMBLY FOR REPAIR 2 CIRCUIT DESCRIPTION 5 COMPONENTS DESCRIPTION 9 SEMICONDUCTOR DATA 11 PARTS LIST 12 EXPLODED VIEW 18 PACKING 19 ADJUSTMENT 20 TERMINAL FUNCTION 29 PC BOARD TX RX UNIT X57 8130 XX 30 SCHEMATIC DIAGRAM 36 BLOCK DIAGRAM 40 LEVEL DIAGRAM 42 SPECIFICATIONS BACK COVER CONTENT...

Page 2: ...am ages resulting from the use of the information contained herein Kenwood reserves the right to make changes to any products herein at any time for improvement purposes 1 Disassembly Procedure 1 When removing the cabinet first remove the two screws from the right and left with a phillips screwdriver Then hook your finger on the edge of the cabinet and pull it out until it is over the chassis prot...

Page 3: ... holder of the key top Panel assembly Display PCB 5 When removing the TX RX PCB first remove the solder of the antenna hot pin and positive terminal of the DC cord Then remove the 15 screws from the TX RX PCB power module and audio amp Positive terminal of the DC cord Antenna hot pin Power module TX RX PCB Audio amp Note When you supply power to the TX RX PCB after removing the TX RX PCB from the ...

Page 4: ...and volume knob r Key top Panel assembly Display PCB Speaker 2 When mounting the panel assembly pass the flat cable through the hole of the chassis as shown below then connect the flat cable to connector of the panel assembly Hole of the chassis Panel assembly Panel assembly Chassis Chassis 3 Fit the panel assembly into the two tabs of the chassis top side first Then fit the panel assembly into th...

Page 5: ...lter MCF XF501 to further remove spurious signals IF Amplifier The first IF signal is amplified by Q503 and then goes to IC501 FM processing IC The signal is heterodyned again with a second local oscillator signal within IC501 to create a 450kHz second IF signal The second IF signal is then fed through a 450kHz ceramic filter Wide CF501 Narrow CF502 to further eliminate unwanted signals before it ...

Page 6: ...of the receive signal can be known before the SQIN voltage is input to the MCU and the scan stop speed is improved Q502 NOISE AMP D503 IC501 IC707 FILOUT RSSI DET MCU FM IC SQIN RSSI Fig 5 Squelch circuit PLL Frequency Synthesizer The PLL circuit generates the first local oscillator signal for reception and the RF signal for transmission PLL The frequency step of the PLL circuit is 5 or 6 25kHz A ...

Page 7: ...o the power module IC302 through a low pass filter The low pass filter removes unwanted high frequency harmonic components and the resulting signal is transmit ted through the antenna terminal See Fig 8 APC Circuit The automatic transmission power control APC circuit detects part of a final amplifier output with a diode D313 D314 and applies a voltage to IC303 IC303 compares the APC control voltag...

Page 8: ...s Each of them is con nected to a cross point of a matrix of the KI1 to KI3 and KSI to KS2 ports of the LCD driver The LCD driver monitors the status of the KI1 to KI3 and KS1 to KS2 ports If the state of one of the ports changes the LCD driver assumes that the key at the matrix point cor responding to that port has been pressed IC901 LCD driver KI1 KI2 KI3 KS2 KS1 FUNC REV CALL VFO MR MHz Encoder...

Page 9: ...s circuit has an overvoltage protection circuit If a DC voltage of 18V or higher is applied to the base of Q707 this voltage turns Q707 on and will set to high on MCU port 18 INT The MCU will then send the backup data to the EE PROM IC708 and enter stop mode See Fig 16 Q714 SW Q713 SW Q707 SW IC713 AVR D712 D710 B IC714 RST SBC R824 R825 INT 5M IC707 MCU POWER SW POWER RESET 5M IC712 INT SB Fig 16...

Page 10: ...ch Q902 DC switch Q903 LCD backlight switch Q904 Brightness function switch D1 Voltage dropped D2 Ripple filter D3 VCO frequency control RX D4 VCO frequency control TX Ref No Use Function Operation Condition Compatibility D5 VCO frequency control RX D6 VCO frequency control TX D7 VCO modulation D8 Ripple filter D9 10 RF switch TX RX D301 Voltage protection 5 1V Zener diode D305 Protection PC TV D3...

Page 11: ...Not used 45 49 NC I Not used 50 AFM O AF mute 51 SPM O Speaker mute 52 AMPSW O AF AMP switch Pin No Name I O Function 53 DT O Common data 54 CK O Common clock 55 NC I Not used 56 DST1 I Destination 1 57 59 DST2 DST4 I Destination 2 4 60 VCC 5V 61 NC I Not used 62 VSS GND 63 ADJ I For adjustment mode 64 NARROW O Narrow 65 WIDE O Wide 66 67 NC I Not used 68 CL O Clock for LCD 69 CE O Chip enable for...

Page 12: ... C9 CK73HB1E104K CHIP C 0 10UF K C10 CC73HCH1H680J CHIP C 68PF J C11 CK73HB1E104K CHIP C 0 10UF K C12 CK73FB1A106K CHIP C 10UF K C14 CK73HB1E104K CHIP C 0 10UF K C15 CK73FB1A106K CHIP C 10UF K C16 CK73HB1H102K CHIP C 1000PF K C17 CK73HB1H103K CHIP C 0 010UF K C18 CK73HB1E104K CHIP C 0 10UF K C20 21 CK73HB1H471K CHIP C 470PF K C23 CK73HB1H471K CHIP C 470PF K C25 C92 0863 05 CHIP TNTL 0 047UF 35WV C...

Page 13: ...23K CHIP C 0 022UF K C533 CC73HCH1H060B CHIP C 6 0PF B C534 CK73HB1A393K CHIP C 0 039UF K C535 CK73HB1H102K CHIP C 1000PF K C537 CC73HCH1H200J CHIP C 20PF J C538 CK73HB1H103K CHIP C 0 010UF K C539 CC73HCH1H020B CHIP C 2 0PF B C541 CK73HB1H102K CHIP C 1000PF K C544 CK73HB1E104K CHIP C 0 10UF K C545 CC73HCH1H130J CHIP C 13PF J C546 CC73HCH1H270J CHIP C 27PF J C547 CK73HB1H102K CHIP C 1000PF K C548 C...

Page 14: ...1E104K CHIP C 0 10UF K C825 CK73FB0J226M CHIP C 22UF M C826 CK73HB1H102K CHIP C 1000PF K C827 CK73FB1E475K CHIP C 4 7UF K C828 CK73HB1H102K CHIP C 1000PF K C829 CK73HB1H103K CHIP C 0 010UF K C830 CK73HB1H102K CHIP C 1000PF K C831 CE32CL1C470M ELECTRO 47UF 16WV C832 CK73HB1E104K CHIP C 0 10UF K C833 835 CK73HB1H102K CHIP C 1000PF K C836 C90 4129 05 ELECTRO 330UF 25WV C837 CK73HB1H103K CHIP C 0 010U...

Page 15: ...W R314 RK73HB1J223J CHIP R 22K J 1 16W R326 RK73HB1J123J CHIP R 12K J 1 16W R331 332 RK73HB1J100J CHIP R 10 J 1 16W R333 334 RK73HB1J101J CHIP R 100 J 1 16W R336 RK73HB1J470J CHIP R 47 J 1 16W R337 RK73HB1J101J CHIP R 100 J 1 16W R338 RK73HB1J154J CHIP R 150K J 1 16W R339 RK73HB1J103J CHIP R 10K J 1 16W R340 RK73HB1J223J CHIP R 22K J 1 16W R341 RK73HB1J154J CHIP R 150K J 1 16W R342 RK73HB1J152J CH...

Page 16: ...766 768 RK73GB2A000J CHIP R 0 0 J 1 10W K R767 768 RK73GB2A000J CHIP R 0 0 J 1 10W M4 R768 RK73GB2A000J CHIP R 0 0 J 1 10W M3 R769 RK73HB1J102J CHIP R 1 0K J 1 16W R770 RK73HB1J000J CHIP R 0 0 J 1 16W R771 RK73HB1J473J CHIP R 47K J 1 16W R772 RK73HB1J103J CHIP R 10K J 1 16W R773 RK73HB1J000J CHIP R 0 0 J 1 16W R774 RK73HB1J472J CHIP R 4 7K J 1 16W R775 RK73HB1J102J CHIP R 1 0K J 1 16W R776 RK73HB1...

Page 17: ... DA2S101 DIODE D709 1SS372F DIODE D710 DA2S101 DIODE D711 1SS372F DIODE D712 UDZW18 B ZENER DIODE D714 Z5W27V SURGE ABSORBER D901 1SS355 DIODE D902 UDZW6 2 B ZENER DIODE IC1 MB15A02PFV2E1 MOS IC IC2 UPB1509GV BI POLAR IC IC302 1B RA60H1317M231 MOS IC POWER MODULE IC303 NJM12904RB1 MOS IC IC501 UA31136L MOS IC IC703 NJM2100V ZB MOS IC IC704 NJM12904RB1 MOS IC IC705 M62363FP F MOS IC IC706 BA10324AF...

Page 18: ...ew of the PCB that part does not come with the PCB These parts must be ordered separately B A 3 2 1 1 10 2 11 13 15 IC302 R380 IC715 J701 B B B B D Dx2 Dx4 X57 A 2 X57 A 2 TX RX unit B 2 Display section TX RX unit A 2 TX RX section Dx2 D D D D A A 700 702 703 A N35 2604 43 B N67 3008 48 C N80 2008 48 D N87 2608 48 3 5 6 12 19 19 16 20 27 30 31 32 36 C C ...

Page 19: ... cord E30 7744 05 18 Fuse Blade type 15A F52 0024 05 26 Holder MIC J19 1584 15 34 Screw set N99 2082 05 28 Bracket J29 0726 03 711 Pamphlet 712 Warranty card K 7 Instruction manual B62 2347 10 K M2 B62 2348 10 M3 B62 2349 10 M4 713 Protection bag 22 Packing fixture H12 4330 02 23 Packing fixture H12 4331 02 24 Item carton case H52 2503 02 K 710 Protection bag ...

Page 20: ...ctrum analyzer Measuring range 10kHz to 1GHz or more 10 Oscilloscope High sensitivity with horizontal input terminal 11 Standard signal generator SSG Frequency range 136 to 174MHz Output 133dBm 0 05µV to greater than 13dBm 50mV 12 Dummy load for AF 8Ω about 5W 13 Sweep generator The sweep generator must be able to sweep the fre quency range of 30 to 300MHz 14 Tracking generator Output voltage 100m...

Page 21: ...n adjustment mode Panel Key Operation Method in Adjustment Mode B qPower switch Volume control wWhen the Tuning control is pressed once the adjustment value display blinks Select an adjustment item with the VFO or MR key before performing the operation It cannot be performed while transmitting When the Tuning control is rotated while the adjustment display is blinking the adjustment value changes ...

Page 22: ...050 CTCSS 88 5Hz Center 155 100 155 050 High 173 900 173 950 9 CTCSS Fine Deviation Narrow Center CT and N icon appear 155 100 155 050 10 DCS Fine Deviation Low DCS icon appear 136 100 136 050 DCS 023N Center 155 100 155 050 High 173 900 173 950 11 DCS Fine Deviation Narrow Center DCS and N icons appear 155 100 155 050 12 DTMF Fine Deviation Center 155 100 155 050 DTMF 9 13 DTMF Fine Deviation Nar...

Page 23: ...6 1 MHz Res BW 100 kHz VBW 100 kHz Span 200 MHz Sweep 50 ms 401 pts 1 Center 136 0500000 MHz Fig 1 Ref 10 dBm Peak Log 10 dB Atten 5 dB Mkr1 155 1 MHz 21 89 dBm W1 S2 S3 FC AA Center 155 1 MHz Res BW 100 kHz VBW 100 kHz Span 200 MHz Sweep 50 ms 401 pts 1 Center 155 0500000 MHz Fig 2 Ref 10 dBm Peak Log 10 dB Atten 5 dB Mkr1 174 0 MHz 23 85 dBm W1 S2 S3 FC AA Center 173 9 MHz Res BW 100 kHz VBW 100...

Page 24: ...m before performing the full reset then write the data to the transceiver after performing the adjust ment Confirm that all LCD segments light 3 VCO Lock voltage RX 1 Frequency 173 950MHz DVM TX RX A 2 CV TX RX A 2 TC2 5 5V 0 1V 2 Frequency 136 050MHz Check 0 5V or more TX 3 Frequency 173 900MHz 4 Transmit TX RX A 2 TC1 5 5V 0 1V 5 Frequency 136 100MHz 6 Transmit Check 0 5V or more Transmitter Sec...

Page 25: ... Linear detector Oscilloscope By turning the Tun ing control adjust the modulation wave until it becomes the square wave Center 3 Adj item BALC Adjust 4 Transmit High 5 Adj item BALH Adjust 6 Transmit Narrow Center 7 Adj item BALC N icon appear Adjust 8 Transmit 5 MAX devia tion Wide Low 1 Adj item MAXL Adjust AG 1kHz 54mV K M2 M3 AG 1kHz 24mV M4 Detector P P LPF 15kHz HPF OFF De emphasis OFF 2 Tr...

Page 26: ... Tuning control Write 0 75kHz 0 05kHz Center 3 Adj item DVC CT icon appear Adjust 4 Transmit High 5 Adj item DVH CT icon appear Adjust 6 Transmit Narrow Center 7 Adj item DVC CT and N icon appear Adjust 8 Transmit 0 37kHz 0 05kHz 8 DCS fine deviation Wide Low 1 Adj item DVL DCS icon appear Detector P P 2 LPF 3kHz HPF OFF De emphasis OFF 2 Transmit 0 75kHz 0 05kHz Center 3 Adj item DVC DCS icon app...

Page 27: ... as shown Refer to Fig 1 page 23 Center 4 Adj item BPC Adjust 5 Spectrum analyzer setting Center f 155 050MHz Span 200MHz RBW 100kHz VBW 100kHz ATT 5dB 6 Tracking generator output 30dBm Refer to Fig 2 page 23 High 7 Adj item BPH Adjust 8 Spectrum analyzer setting Center f 173 950MHz Span 200MHz RBW 100kHz VBW 100kHz ATT 5dB 9 Tracking generator output 30dBm Refer to Fig 3 page 23 2 Squelch Tight W...

Page 28: ...just 6 SSG output 124dBm 0 14µV Narrow Center 7 Adj item SQOC N icon apper Adjust 8 SSG output 124dBm 0 14µV SSG MOD 1kHz SSG DEV 1 5kHz 4 RSSI writing 1 Frequency 155 050MHz 2 SSG output 53dBm 501µV SSG MOD 1kHz SSG DEV 3kHz RSSI value writing is performed by the Squelch open item center wide SSG output level is changed and ad justed after Squelch adjustment This adjustment should not turn the Tu...

Page 29: ... External speaker 2 GND GND TX RX unit X57 8130 XX B 2 Display Section Pin No Name I O Function CN901 1 SPGND AF GND 2 SPGND AF GND 3 SPOUT I AF out 4 SPOUT I AF out 5 8C I 8V DC supply 6 RXD O RXD PC serial data 7 PTT O PTT PC serial data 8 VOL O Volume 9 MICKEY O Microphone key 10 5C I 5V DC supply 11 CM O Microphone key check 12 ENCA O Encoder A 13 ENCB O Encoder B 14 DI O Data from LCD driver ...

Page 30: ...C712 O G I R809 R822 R824 R825 R826 C801 C806 C810 C817 C822 C830 C832 C838 Q714 G S D R737 R739 R757 R758 R761 R765 R769 R770 R771 R772 R774 C749 C753 C763 C767 C774 C775 C776 IC708 IC711 O G I R817 R818 R819 R832 R833 R834 R841 R843 C816 C820 C827 C834 C850 Q704 Q705 Q712 R505 R507 R701 R702 R703 R704 R705 R706 R707 R708 R337 C508 C509 C702 C703 R749 C713 SPGND SPGND SPOUT SPOUT 8C RXD PTT VOL M...

Page 31: ...408 C409 C412 Q506 Q708 R508 R509 CN501 R520 R521 R529 R338 R340 R342 R344 R348 TH501 R351 TH703 C514 C524 C525 C333 C334 R377 C530 C342 C347 D301 C556 D305 D503 D504 C565 D314 D316 C575 IC303 C579 TX RX UNIT X57 8130 XX A 2 TX RX SECTION 10 K 21 M2 22 M3 23 M4 Component side view J79 0316 09 A 2 Component side Foil side Layer 1 Layer 2 PC BOARD TM 281A Ref No Address IC302 3K IC303 8P IC707 9F IC...

Page 32: ...5 C365 R789 D309 C560 R790 C562 R794 D505 D311 R796 7 1 C566 C567 D508 D509 C569 C570 C571 C574 C576 C578 C581 C582 C397 C399 X1 C784 C787 C788 IC710 3 1 4 5 C11 C14 C15 C16 C405 C406 D306 D307 L317 C34 C38 C41 C46 C52 C53 C55 C56 C58 Q10 C65 C68 C69 C71 C420 L320 D4 D7 D9 Q504 Q505 G1 S S D D G2 G1 G2 L507 L511 D10 L7 L10 L11 L14 L21 R534 R540 R541 R542 R544 R545 R547 R556 R24 R25 R26 R29 Q5 R31 ...

Page 33: ...24 R744 R746 C724 C732 C734 C740 C745 C746 C748 C750 C754 R799 D702 D704 D705 D706 D709 D711 IC709 C790 C794 C797 C798 4 4 5 1 8 5 1 8 C799 C818 C825 C831 C840 C844 IC706 J701 EXT SP C836 C839 R830 TX RX UNIT X57 8130 XX A 2 TX RX SECTION 10 K 21 M2 22 M3 23 M4 Foil side view J79 0316 09 A 2 Component side Foil side Layer 1 Layer 2 PC BOARD TM 281A J79 0316 09 A 2 Ref No Address IC1 9I IC2 8F IC50...

Page 34: ...D908 D909 D911 Q901 Q902 R914 R915 R918 R920 R921 R922 R923 R924 C901 C902 C912 C915 C916 C917 C918 C929 D901 D902 SPGND 1 22 SPGND SPOUT SPOUT 8C RXD PTT VOL MICKEY 5C CM ENCA ENCB DI DO CE CL BRI POWER MIC ME GND TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION 10 K 21 M2 22 M3 23 M4 Component side view J79 0316 09 B 2 TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION 10 K 21 M2 22 M3 23 M4 Foil side view J7...

Page 35: ...PLAY SECTION 10 K 21 M2 22 M3 23 M4 Component side view J79 0316 09 B 2 TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION 10 K 21 M2 22 M3 23 M4 Foil side view J79 0316 09 B 2 Component side Foil side Layer 1 Layer 2 Component side Foil side Layer 1 Layer 2 PC BOARD TM 281A J79 0316 09 B 2 J79 0316 09 B 2 Ref No Address D903 6K D904 6G D905 6O D906 4F D907 4G D908 4H D909 4I D910 4L D911 4J Ref No Addres...

Page 36: ...n C38 10p L9 270n L14 27u C50 10p R33 100 L16 27u C52 11p L1 L18 33n D7 1SV278F IC704 NJM12904RB1 1 2 3 4 5 6 7 8 VCC SPLATTER FILTER W NI EVOL1 5C VCO CV VOLTAGE DROPPED SWITCHING OP AMP TCXO IDC DETECTION BUFFER AMP CK CPU54 DT CPU53 DT CPU53 HPF TX RX UNIT X57 8130 XX A 2 TX RX SECTION W NO EVOL2 PLLE CPU3 FRQO UL CPU21 CK CPU54 PLLE CPU3 8CL 8CL RIPPLE FILTER DIGITAL POTENTIOMETER OSCILLATOR M...

Page 37: ... L514 68n L515 68n C546 27p C765 1000p R760 47k L19 R779 47k 5M C574 1 5p C570 1p 2SK3019 Q705 2SK3019 Q704 8TC CPU80 FM IC BPF 5M WIDE CPU65 TXD RXD RF SWITCH NARROW NARROW CPU64 D505 506 IF SWITCH RF BPF TUNING D508 509 IF AMP 50 4MHz 8R 8R IF SWITCH W NI EVOL1 EEPROM RF AMP MCU AFV AF MUTE AF MUTE VOLI EVOL13 DIVIDER AFM CPU50 WIDE TRIPLER RF BPF TUNING MIXER RF AMP 8RC CPU76 8TC CPU80 AMPSW CP...

Page 38: ...4 ANT SWITCH D702 704 706 8TC CPU80 8RC CPU79 RX 5C DETECTION VOLTAGE DETECTION INT DC SWITCH SB 8C W NO EVOL2 SQL AMP Q708 710 8C SB OVER VOLTAGE DETECTION SURGE ABSORPTION AF MUTE AF MUTE 8R POWER IC715 LA4600 1 2 3 4 5 6 7 8 9 10 PTT BRI RXD POWER VOL 8C 5C DO CL CE DI MICKEY ENCB CM ENCA DC SWITCH 8R DC SWITCH 8T PROTECTION BRI AUDIO AMP RD00HVS1 T113 AMPSW CPU52 MIC 8TC CPU80 SPM CPU51 8RC CP...

Page 39: ...1 COM2 SEG13 COM1 RESISTOR COM3 SEG24 SEG1 LCD SEG17 SEG27 SEG29 SEG4 SEG26 SEG31 SEG5 SEG14 SEG18 SEG19 VARIABLE SEG8 SEG12 SEG2 SEG20 LED TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION SEG22 MR SEG0 SEG16 COM0 SEG6 SEG28 SEG25 SEG30 ENCODER LCD DRIVER KEY BACKLIGHT SWITCH BRIGHTNESS FUNCTION SWITCH D903 905 LCD BACKLIGHT SWITCH DC SWITCH LED 2 3 4 5 6 7 8 8 9 10 11 12 13 14 15 16 17 18 Func CALL VFO...

Page 40: ...OWER 5C BRI CL POWER D903 D905 1SS372F D709 X1 KS2 MIC MIC AMP GND 5C CM ENCA VOL ME GND AMP L77 1944 05 TCXOMOD TCXO ENCB COM0 3 SEG0 31 KI2 KI1 KI3 KS1 KS2 SW 2SB1132 Q R Q903 LCD ILLUMINATION D906 D911 B30 2337 05 UMG3N Q904 BRI SW 8C MICMT MUTE SW 5C DET D HSB N 8CL DA2S101 D8 PUMP CHARGE D708 DA2S101 IC704 NJM12904RB1 FILTER SPLATTER 8C SPGND IC706 1 4 BA10324AFV AMP SUM 8C DTMO 5C M62363FP F...

Page 41: ... M4 272 000 347 995MHz M2 M3 288 000 295 995MHz K M4 RX 136 000 173 9975MHz K M2 M3 144 000 147 9975MHz M4 TX 136 000 173 9975MHz M2 M3 144 000 147 9975MHz K M4 SW RF BPF 5M IF Q712 HSC277 EXT 16 8MHz 3SK318 2SJ645 5V VCO RF BPF 8R IC714 MCH3914 7 H EEPSDT IC501 SW RT1N141U T111 AMPSW Q715 RSSI SQIN 8C UA31136L AMP COMM AMP D9 D10 HSB88AS E DETECTOR IC303 NJM12904RB1 AMP RSSI RT1N141U T111 5V FB 5...

Page 42: ...n the AF section connect the AC level meter AG is set so that MIC input becomes 3kHz 1 5kHz Wide Narrow DEV at 1kHz MOD D CF501 CF502 450kHz 7 IC706 TX RX Unit S IC501 5 49 95MHz 9 IC703 G1 20 1 Center Frequency W 123 5dBm N 123 5dBm W 120 0dBm N 120 0dBm W 103 5dBm N 104 0dBm W 107 5dBm N 108 5dBm W 0 63Vrms N 0 31Vrms W 0 36Vrms N 0 18Vrms W 109 0dBm N 109 5dBm W 97 0dBm N 96 0dBm W 80 5dBm N 78...

Page 43: ... VOL control Q6 vel meter 12dB SINAD TX RX Unit Q9 7 11 Q10 Power Module Q303 2 D9 D10 TX RX Unit S IC2 Audio Frequency D TX RX Unit VCO CF501 CF502 450kHz G IC501 D306 D307 ANT 3 5dBm 10dBm 3 7dBm 65W K M2 M3 25W M4 W 84 5dBm N 84 5dBm W N 0 54Vrms W N 0 45Vrms W N 0 42Vrms W N 0 45Vrms W N 0 47Vrms W N 10mVrms W N 0 70Vrms W N 0 64Vrms 4 0dBm 14 J1 IC705 12 Q706 8 9 13 8ohm 10 IC709 7 IC715 IC70...

Page 44: ...Ω Usable Temperature Range 20 C 60 C 4 F 140 F Power Supply 13 8V DC 15 11 7 15 8V Grounding Method Negative ground Current Transmit max K M2 M3 14A or less M4 8A or less Receive at 2W output 1 0A or less Frequency Stability 20 C 60 C Within 2 5ppm Dimensions W x H x D projections not included 160 x 43 x 126 mm 6 30 x 1 69 x 4 69 in Weight Approx 1 13kg 2 5lb RECEIVER Circuitry Double conversion s...

Page 45: ...67 C774 C775 C776 IC708 IC711 O G I R817 R818 R819 R832 R833 R834 R841 R843 C814 C816 C820 C827 C834 C850 Q704 Q705 Q712 R504 R505 R507 R701 R702 R703 R704 R705 R706 R707 R708 R337 C508 C509 C702 C703 R749 C713 SPGND SPGND SPOUT SPOUT 8C RXD PTT VOL MICKEY 5C CM ENCA ENCB DI DO CE CL BRI POWER MIC ME GND 1 22 R752 R753 C718 C719 C720 R763 R764 R766 R767 R768 R773 R775 R776 R778 R779 R780 R782 R783...

Page 46: ...0 L320 D4 D7 D9 Q504 Q505 G1 S S D D G2 G1 G2 L507 L511 D10 L7 L10 L11 L14 L21 R534 R540 R541 R542 R544 R545 R547 R556 R24 R25 R26 R29 Q5 R31 R34 C537 C539 R42 R43 R45 C557 C558 C561 D506 C568 C573 C60 C62 C63 C64 C66 R512 R514 R525 IC2 C517 C519 C520 C521 C522 Q6 Q9 C527 C533 IC501 C583 R522 C36 C39 C45 C51 C57 D3 L502 R502 L6 L15 C506 CD501 R28 Q4 R30 R32 R38 C20 C21 C23 C25 C27 C28 C29 C61 C804...

Page 47: ...POUT 8C RXD PTT VOL MICKEY 5C CM ENCA ENCB DI DO CE CL BRI POWER MIC ME GND TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION 10 K 21 M2 22 M3 23 M4 Component side view J79 0316 09 B 2 TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION 10 K 21 M2 22 M3 23 M4 Component side view J79 0316 09 B 2 TX RX UNIT X57 8130 XX B 2 DISPLAY SECTION 10 K 21 M2 22 M3 23 M4 Foil side view J79 0316 09 B 2 TX RX UNIT X57 8130 XX ...

Page 48: ... CPU3 8CL D309 311 8CL RIPPLE FILTER DIGITAL POTENTIOMETER TEMPERATURE COMPENSATION NARROW CPU64 1 2Vcc OSCILLATOR MODI EVOL9 5M D505 506 LIMITER IF SWITCH RF BPF TUNING D508 509 IF AMP 8T Q1 2 Q709 711 APC VOLTAGE DETECT D4 6 VOLTAGE DETECTION RESET D313 314 8C D3 5 50 4MHz ANT SWITCH D702 704 706 8TC CPU80 8RC CPU79 8R RX 8R IF SWITCH W NI EVOL1 EEPROM RF AMP 5C MOD DETECTION MODULATION 8C VOLTA...

Page 49: ...14 PLLE TX RX UNIT X57 8130 XX B 2 Display section TX RX UNIT X57 8130 XX A 2 TX RX section SP MCH3914 7 H BL LCD DRIVER IC901 PT6554LQ LCD DISPLAY POWER 5C BRI CL POWER D903 D905 1SS372F D709 EEPSDT X1 IC501 SW RT1N141U T111 AMPSW Q715 RSSI SQIN 8C KS2 MIC MIC UA31136L AMP COMM AMP D9 D10 HSB88AS E DETECTOR IC303 NJM12904RB1 AMP RSSI RT1N141U T111 5V FB AMP GND 5C CM ENCA VOL ME GND AMP L77 1944 ...

Page 50: ...it VCO MIC To make measurements in the AF section connect the AC level meter AG is set so that MIC input becomes 3kHz 1 5kHz Wide Narrow DEV at 1kHz MOD D CF501 CF502 450kHz 7 G IC706 TX RX Unit S IC501 5 49 95MHz D306 D307 9 IC703 G1 20 1 ANT Center Frequency 3 5dBm 10dBm 3 7dBm 65W K M2 M3 25W M4 W 123 5dBm N 123 5dBm W 120 0dBm N 120 0dBm W 103 5dBm N 104 0dBm W 107 5dBm N 108 5dBm W 0 63Vrms N...

Search results

Summary of Contents for TM-281A

Reviews:

Related manuals for TM-281A

Brands by name

Popular brands

Kenwood TM-281A, Service Manual

Search results

Summary of Contents for TM-281A

Reviews:

Related manuals for TM-281A

Brands by name

Popular brands