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DESCRIPTION
OPERATING THEORY- PLL FREQ. S Y N TH E S IZE R ....................................................................1-4
FREQUENCY CHART (TABLE 1)....................................................................................... ...................5
BLOCK DIAGRAM..................................................................................................................................... 6
PLL CIRCUIT BLOCK DIAGRAM............................. .............................................................................7
ALIGNMENT PROCEDURE................
TEST EQUIPMENT SET-UP................................................
VOLTAGE CHART, IC'S & TRANSISTORS........................................................................................ 13
PARTS LAYOUT, PCB401068-F, TOP VIEW.......................................................................................14
COMPOSITE LAYOUT, PCB401068-F, TOP VIEW ......................................................................... 14
COMPOSITE LAYOUT, PCB 401377-C, 401261-B, TOP VIEW........................................................ 14
PARTS LAYOUT, PCB401068-F, BOTTOM VIEW ........... ...................................................................15
PARTS LAYOUT, PCB 401377-C, 401261-B, BOTTOM VIEW............................................................15
COMPOSITE LAYOUT, PCB401068-F, BOTTOM VIEW.....................................................................16
COMPOSITE LAYOUT, PCB 401377-C, 401261-B, BOTTOM VIEW................................................... 16
COPPER PATTERN, PCB401068-F, BOTTOM VIEW.........................................................................17
COPPER PATTERN, PCB 401377-C, 401261-B, BOTTOM VIEW.......................................................17
WIRING DIAGRAM, CHASSIS & MIC PINS.......................................................................................... 18
PCB 401068-D WIRING DIAGRAM.........................................................................................................19
SEMICONDUCTOR PIN CONFIGURATION.......................................................................................... 20
I.C. DIAGRAMS, LM6416E, LC7131, TA7310P..................................................................................... 21
I.C. DIAGRAMS, KIA7217AP, TL489CP, MC78L08CT........................................................................... 22
EXPLODED VIEW PARTS LIST.............................................................................................................23
EXPLODED VIEW................................................
SCHEMATIC DIAGRAM.....................................................................................................
PARTS LIST........................................................
TA B LE O F C O N TE N TS
M odel 19 Plus
PAGE NUMBER
8-11
12
24
25
25

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Table of Contents
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Summary of Contents for Cobra 19 Plus

  • Page 1: Table Of Contents

    TA B LE O F C O N TE N TS M odel 19 Plus DESCRIPTION PAGE NUMBER OPERATING THEORY- PLL FREQ. S Y N TH E S IZE R ..............1-4 FREQUENCY CHART (TABLE 1)......................5 BLOCK DIAGRAM............................. 6 PLL CIRCUIT BLOCK DIAGRAM......................7 ALIGNMENT PROCEDURE....
  • Page 2: Operating Theory- Pll Freq. S Y N Th E S Ize R

    OPERATING THEORY OF PLL FREQUENCY SYNTHESIZER FOR MODEL 19 PLUS Fundamental Theory Of PLL Circuitry The purpose of (Phase Locked Loop) circuit is to generate multiple number programable frequencies from a signal reference frequency with quartz erystal accuracy. A basie PLL circuit consists of reference oscillator, VCO, phase comparator and DC filter (Iow pass filter).
  • Page 3 VCO frequency by 3254. 16270 3254 5kHz Note that reference frequency 5kHz obtained dividing the 10.24MHz 2048 times. (5kHz reference is used instead of 10kHz division convenience). See table 1 for transmit/receive mode VCO frequencies. 19 PLUS -2-...
  • Page 4 L305 C317 are sériés résonant , and RFC303, L306, RFC304, C321, 322, C326 make up PI-LOW pass filter. C312 is factory selected limits the RF output level to within the FCC limit of 4 watts. 19 PLUS -3-...
  • Page 5 5 channels per second. the microprocessor During channel sélection or scan function, unit, prevent inhibits transmitter section undesired signais from being radiated. 19 PLUS -4-...
  • Page 6: Frequency Chart (Table 1)

    2 7.3 5 5 16.67 17.125 27 .3 65 16.68 17.135 2 7 .3 7 5 17.145 16.69 2 7 .3 8 5 17.155 16.70 2 7 .3 9 5 16.71 17.165 2 7 .4 0 5 19 PLUS -5-...
  • Page 7: Block Diagram

    Block Diagram...
  • Page 8: Pll Circuit Block Diagram

    T X -...
  • Page 9: Alignment Procedure

    ALIGNMENT PROCEDURE FOR CB TRANSCEIVER MODEL 19 PLUS TEST EQUIPMENT REQUIRED All Test equipment should be properly calibrated. Audio Signal Generator, 10Hz - 20kHz VTVM 1mV measurable. DC Ammeter, 2A Regulated Power Supply, de 0-20V, 2A or higher, Frequency Counter, 0-40MHz, high input impédance type.
  • Page 10 RF power output, always use the supplied de cable. RF Amplifier State Alignment Reduce power supply voltage to 9.0V. channel selector to 19 and connect the oscilloscope to the antenna connector through a suitable connection pad. 19 PLUS -9-...
  • Page 11 When applying audio modulation signal to the microphone input circuit, use the same plug. Next, reduce the signal input level to 4.5mV, and make sure that the modulation is higher than 60%. 19 PLUS -10-...
  • Page 12 447 micro^olts. The receiver should squelch. (The audio output level should drop to zero.) Reduce the antenna signal input level to zero, and adjust the SQ control until the noise output just disappears. 19 PLUS -11-...
  • Page 13: Test Equipment Setup

    Test Equipment Setup PLL AND CARRIER SECTION P.T.T RECEIVER SECTION TRANSMITTER SECTION 19 PLUS -12-...
  • Page 14: Voltage Chart, Ic's & Transistors

    0 .0 7 0 .0 7 1.27 7.08 6.11 6.86 6 .7 2 2 .0 2 2.12 4.10 1.45 0 .0 3 0 .0 3 5.10 5.50 5.88 5.92 3.23 2.83 7.08 1.27 3.83 3.83 5. 14 5. 16 19 PLUS -13-...
  • Page 15: Parts Layout, Pcb401068-F, Top View

    ß CÛ ■ 19 PLUS -14-...
  • Page 16: Parts Layout, Pcb401068-F, Bottom View

    H I-Q T -x L [ y l ü ü ) s QSiOlJP. CI34 - ) | - I § I f e u r — C32I i „ • □ □ □ □ □ O O O O O 19 PLUS -15...
  • Page 17: Composite Layout, Pcb401068-F, Bottom View

    P.C.B Bottom View 19 PLUS -16-...
  • Page 18: Copper Pattern, Pcb401068-F, Bottom View

    401377-с' 19 PLUS -17-...
  • Page 19: Wiring Diagram, Chassis & Mic Pins

    Wiring Diagram (Chassis and Microphone Pins) S P E A K E R A N T POWER JACK VOLUME SQUELCH POWER GRN ( 0 . 5 - 4 - 0 . 5 ) ON/ OFF SW DIN JACK 19 PLUS -18-...
  • Page 20: Pcb 401068-D Wiring Diagram

    P.C.B Wiring Diagram ( 3 - 1 6 - 3 ) BRN ( 3 - 1 3 - 3 ) ш > 19 PLUS -19-...
  • Page 21: Semiconductor Pin Configuration

    U Z P - 8 .2 B IN 4 0 0 2 B Z X 8 3 -C 5 V 6 IS 2 4 7 3 OA 90 ł ł LD-OOIVR L T D - 4 8 2 6 - Y 19 PLUS -20-...
  • Page 22: Diagrams, Lm6416E, Lc7131, Ta7310P

    - O EXTAL : CARRY FF - O VOD ; PROGRAM COUNTER - O VSS LC 7131 ( I) (2 ) (4 ) (5 ) (6 ) (8 ) ( 9 ) (16) T A 7 3 I0 P 19 PLUS -21-...
  • Page 23: Diagrams, Kia7217Ap, Tl489Cp, Mc78L08Ct

    BOOT STRAP D.C : DECOUPLING P.C : PHASE COMPENSATION T L 4 8 9 CP DIG ITAL OUTPUTS 19 PLUS -22-...
  • Page 24: Exploded View Parts List

    625007 Washer (Lock "B" Type) M5 664518 (+) Machine Screw (F.H) M2.6 x 4 611086 (+) Tapping Screw (B.H) 3 x 8-2S 623344 (+) Тар Tite Screw (B.H) 633082 (+) Machine Screw (B.H) М3 x 10 613332 19 PLUS -23-...
  • Page 25: Exploded View

    Exploded View 19 PLUS -24-...
  • Page 27: Parts List

    PARTS LIST 19 PLUS PARTS LIST 19 PLUS P A R T N 0. D E S C R IP T IO N S Y M B O L P A R T N0. D E S C R IP T IO N...

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