Midland Radio SP-300 -

PAGE -43-

May 2001

Notes:

1. ALL VALUES ARE IN OHMS,

MICROHENRIES OR MICROFAR-

ADS UNLESS OTHERWISE SPECI-

FIED.

2. ALL RESISTORS ARE 1/10W 5%

UNLESS OTHERWISE SPECIFIED.

TCXO

Schematic P/N: 770-100-0002 Rev. D

PCB Assy. P/N: 650-100-0002 Rev. D

ACC-200 BATTERY

Schematic P/N: 770-210-0010

Shown for reference only

FUSE

Schematic P/N: 770-200-0004 Rev. B

PCB Assy. P/N: 650-200-0004 Rev. B

P.T. T.

Schematic P/N: 770-180-0017 Rev. A

PCB Assy. P/N: 480-042-0028

SW401

MON

(OPTION1)

SW402

PTT

CON401

4PIN(M)

CON402

4PIN(F)

SW403

OPTION2

C412

470PF

C411

470PF

C410

470PF

2431

PTT

GND

OPT2

OPT1

C405

47P

C403

47P

C401

47P

C402

470P

FUSE 4A

C404

470P

CON1

C406

470P

4

Q702

MMBR9426

R714

2.2K

Q701

MMBR9426

R710

2.2K

C705

100pF

R713

47K

R707

47K

X701

12.8MHz

R708

47K

C703

91pF

R705

47KD702

MMBV109

R706

47K

D701

MMBV

105

R703

*

R702

*

TH703

150K

R704

*

LK701

2

R701

*

TH701

10K

1

TH702

33K TC701

20pF

C701

100pF

C702

100pF

R709

39K R711

4.7K

C704

180pF

R712

39K

C706

220pF

R715

2.2K

3

CON1

BATT 7.5V

+

SW1

SWPOLY

R1

15K

D1

TH1

30K

-

Contents

Main TABLE OF CONTENTS Page SPECIFICATIONS GENERAL TEMPERATURE RANGE CURRENT CONSUMPTION Page RECEIVER Page SP-300 Series HAND HELD INTRODUCTION FEATURES Main Features Wideband Scan Mode Scan Delay Time Busy Channel Lockout Marked Idle Enable Normal/Inverted DCS Standard/Non-Standard CTCSS SP-300 Series HAND HELD VCO Lock Time Low Battery Indication Memory Protect External Option Detect maxon DESCRIPTION OF CONTROLS THEORY OF OPERATION DIGITAL CIRCUITS z RF CIRCUITS RF CIRCUITS PLL SYNTHESIZER RECEIVER Page MAINTENANCE AND REPAIR GENERAL REMOVING & REPLACING THE BELT CLIP REMOVING & REPLACING THE BATTERY REMOVING & REPLACING PTT ASSY. REMOVING & REPLACING THE ACCES- SORY CONNECTOR REMOVING & REPLACING THE ANTENNA & CONTROL KNOBS REMOVING & REPLACING THE BACK COVER REMOVING & REPLACING THE MAIN BOARD z Page REMOVING & REPLACING THE DAUGH- TER BOARDS z REMOVING & REPLACING THE SPEAKER COMPONENT REPLACEMENT z PROGRAMMING ALIGNMENT PROCEDURE z Page -23- TEST EQUIPMENT SETUP 1. S.S.G. : @ 1kHz Audio: 154.625445681125661 ALIGNMENT POINTS DIAGRAM ALIGNMENT POINTS VHF & UHF WITH TCXO MODULE ALIGNMENT POINTS UHF WITH OUT TCXO MODULE Page -25- TROUBLESHOOTING GUIDE Page -26- VOLTAGE CHARTS z z z CONTROL CIRCUIT RX SP-300 HAND HELD z RECEIVE STATE Page -28- TRANSMIT STATE Page -29- SP-300 SERIES UHF & VHF DIGITAL SECTION PARTS LIST Page -30- Page -31- SP-300 SERIES VHF RF SECTION PARTS LIST Page -32- Page -33- Page -34- SP-300 SERIES UHF RF SECTION PARTS LIST Page -35- Page -36- Page Page -38- COMPONENT PINOUT MMBR951 Q16,17,501,601 KRA104S (PD) Q5,410,412 KRA102S (PB) Q1 D405, 406, 407 Page -39- REFERENCE NO. SCHEMATIC D15 D201,202,301 Page -40- PIN DESCRIPTION 1 12 15 RX/TX VCO SCHEMATICS & BLOCK DIAGRAM ues may differ from schematics shown. VHF FRONT-END Schematic P/N: 770-110-0012 Rev. C PCB Assy. P/N: 650-110-0012 Rev C VHF POWER AMP VCO TX VCO R X 97 10 8 13 - 3 1 47K MMBR9426 PAGE -44- May 2001 Digital Schematic PTT SCHEMATIC P/N:480-042-0028 DESCRIPTIONDESCRIPTIONREV ARELEASED TO MANUFACTURING DGC 5/01 SP-300 Series Digital Schematic Diagram VHF RF Schematic AUDIO AMP DESCRIPTIONDESCRIPTIONREV VCO RX SECTION FUSE SCHEMATIC P/N: 650-200-0004 PAGE -46- May 2001 UHF RF Schematic P.A. MODULE(UHF) SCHEMATIC P/N: 650-230-0013 VCO TX SECTION (UHF) P/N: 650-030-0020 VCO RX SECTION FRONT-END (UHF) SCHEMATIC P/N: 650-110-0013 FUSE SCHEMATIC P/N: 650-200-0004 Block Diagram REVISIONS NA DESCRIPTIONDESCRIPTION RELEASED TO MANUFACTURING REV A PCB LAYOUTS TCXO1 VR3 J3 Board Layout (Top) Main Board Assembly 416121B Exploded View SEE NOTE 3 SEE NOTE 1 SEE NOTE 2