Kenwood TH-28A Service Manual

144MHz FM TRANSCEIVER
~TH-28A/E
SERVICE MANUAL
© 1992-5 PRINTED IN JAPAN
KENWOOD >
B51-8170-00(0) 1209
--- CONTENTS
CIRCUIT DESCRIPTION
...ssccsssecsssscsssecseseesetenneetsns 2
DESCRIPTION OF COMPONENTS. .........-2s0000 13
SEMICONDUCTOR DATA ....sscssesesscseceesessessneerens 16
PARTS LIST ssscssssssssessssssscssssessseeessecseeeeeareseesneess 22
EXPLODED VIEW
sssesssssscssssscssseceseeseeateatsueesnneens 37 -
PACKING
vicccssescsssssessssseccssnessssesessesesesstansatesneeennes 38
ADJUSTMENT
oiscssssssscsscccsssscssessscesssnseseeessteserenees 39
POWER MODULE INSTALLATION METHOD ......... 43
TERMINAL FUNCTION. .....c.ssscsssscsseieceesesessneeeees 44
(190 0445-05)
PC BOARD VIEWS
TX-RX UNIT : IF (X57-404X-XX) (A/2). essen 45
TX-RX-UNIT-; RF-(X57-404X-XX)}(B/2) 49 -
.
CONTROL UNIT (X53-340X-XX) (A/5) .-e-s- 53
Coe 1634-13) : KM, M2, X, P
CONTROL UNIT : CHARGER (X53-340X-XX) (B/S) ...... 55
(A02-1634-13) : T, E, E2, 3, £6
CONTROL UNIT : PTT (X53-340X-XX) (C/5) sseessssssensee 55
Knob ENC)
CONTROL UNIT : VOL/SOL (X53-340X-XX) (D/5) ......- 56
Knob (VOL
(K29-4774-04)
CONTROL UNIT : ENCODER (X53-340X-XX) (E/5) s..sesssn 56
({K29-4772-04)
VCO (X58-3870-XX) « ..eeeseecceseneseneceeneeenensseces
SCHEMATIC DIAGRAM. ...ssecsesscssssensessesseestenssanss
BLOCK DIAGRAM. ...sseseesssssssesssssssetseeeee eeeeeesseeees
Knob (SQL)
LEVEL DIAGRAM
....eeccesecsseteceesesestiereeseesnenecenvess
(K29-4773-04)
(K29-4775-13)
Knob (LOCK)
(K29-4777-04)
Front glass
(B10-1179-04)
Knob
(K29-4776-03)
Knob (Key top)
(K29-4778-03)
PHOTO is TH-28A
RRS ne ens nape spent
BC-15A (RAPID CHARGER)
HMC-2 (HEAD SET WITH VOX & PTT) ..eseeeeeeeees 66
ME-1 (MEMORY EXPANSION UNIT) .........004+ 68
PB-13 (Ni-Cd BATTERY) ...ssssscsccssssseeeesseseessssnees 68
PB-14 (Ni-Cd BATTERY)
wessssssssstssseeeseseeeeeeeee 69
PB-17 (HIGH POWER BATTERY PACK)... 70
PB-18 (LONG LIFE BATTERY PACK) ........--.+++ 70
PG-2W (DC CORD) o.eescsescssessesstsssesseesesserseeeacees 71
PG-3H (FILTERED CIGAR LIGHTER CORD) ....... 71
SMC-31, 32, 33 (SPEAKER MICROPHONE) ....... 72
TSU-7/CTCSS UNIT (X52-3170-00) .....seeeeeeeens 73
BH-6 (SWIVEL MOUNT) o....ecsssesssccssseseeeessseerseeens 75
HB-2 (HAND STRAP) n.ccessessseccsecssecssscseevecseseseeees 75
SC-30, 33, 34 (SOFT CASE) ciescsssccecsseesseeeeees 75
WR-2 (WATERPROOF CASE) ......sssscceeesesseeseeees 75
SPECIFICATIONS oo... eessseesseesseesssees BACK COVER