HP 9800 54

CIRCUIT DESCRIPTION

800/900 MHz TRANSMITTER DESCRIPTION

Over Current Shutdown

Current to the second and third amplifier stages in power module U600 on the PA board is monitored by sensing the voltage drop across R601. Pins 5 and 6 of U500B are effectively connected across this resistor.

As current increases, the voltage on U500B, pin 6 decreases which causes the output voltage on pin 7 to increase. The gain of each U500B input is set at about ten by R509/R504 and R502/R507.

Emitter biasing for Q501 is provided by R506 and R511. Normally, the output voltage of U500B is not high enough to turn on Q501. However, if current becomes excessive, for example because of an antenna mismatch, Q501 begins turning on. This decreases the base voltage of Q502 which turns off Q500 slightly and cuts back power output. Over-current shutdown is disabled in 15-watt models because CR500 is not used.

	February 2001
3-32	Part No. 001-9800-001

Contents

25 or 40 Watts (UHF); 15 or 30 Watts (800/900 MHz) 13.6 VDC Part No 13.6 VDC 25 or 40 Watts, UHF 15 or 30 Watts, 800/900 MHz Part No. 242-984x-2xx(UHF) Part No. 242-988x-2xx(800 MHz) TABLE OF CONTENTS 1 GENERAL INFORMATION 3 CIRCUIT DESCRIPTION 2 INSTALLATION TABLE OF CONTENTS (CONT’D) 4 SERVICING 5 PARTS LIST 6SCHEMATIC DIAGRAMS AND COMPONENT LAYOUTS LIST OF TABLES LIST OF FIGURES SECTION 1 GENERAL INFORMATION 1.3 PART NUMBER BREAKDOWN Table 1-1Part Number Breakdown 1.4 TRANSCEIVER IDENTIFICATION Table 1-2Identification Number Breakdown Type 1.5 ACCESSORIES Table 1-398xx Accessories Accessory Cable Data/Accessory Cable Desktop Accessories 1.6 PRODUCT WARRANTY 1.7 FACTORY CUSTOMER SERVICE 1.8 FACTORY RETURNS 1.9 REPLACEMENT PARTS 1.10 INTERNET HOME PAGE UHF 984x SPECIFICATIONS 800 MHz 988x SPECIFICATIONS 900 MHz 989x SPECIFICATIONS SECTION 2 INSTALLATION 2.2 MOUNTING THE TRANSCEIVER WARNING Item Figure 2-2Remote Mount Installation Components 2.3 POWER CABLE INSTALLATION Figure 2-3Accessory Cable Installation 2.4 ACCESSORY CABLE INSTALLATION Function Figure 2-4Accessory Cable Connector Figure 2-5R170 Location Diagram Sw Bat Out (pin 2) Horn Alert (pin 4) - See Section Ignition Sense (pin 6) - See Section Output D (pin 7) 2.5 REMOTE CONTROL UNIT INSTALLATION Figure 2-6Data Cable Installation (-001Cable Shown) 2.6 USING AN EXTERNAL SPEAKER 2.7 DATA CABLE INSTALLATION CAUTION Table 2-1Data Cable Wire Chart J301 Pin No Wire Color 2.8 KEY CAP KITS EMER F1 F2 F3 SCAN SCAN BKLHT MSG HORN SECTION 3 CIRCUIT DESCRIPTION POWER DISTRIBUTION (ALL MODELS) 3.2 POWER DISTRIBUTION AND SWITCHING Figure 3-1Power Distribution and Switching Figure 3-2Power On-OffControl Circuit AUDIO/LOGIC DESCRIPTION (ALL MODELS) 3.3 AUDIO/LOGIC BOARD DIGITAL CIRCUIT VRH/VRL PE0 PE1 PE2 PE3 PA0 PA1 PA2 PA3 PA4/PA5 3.4 RECEIVE AUDIO/DATA PROCESSING Figure 3-3Audio and Data Processing Circuitry Block Diagram 3.5 TRANSMIT AUDIO/DATA PROCESSING 3.6 DISPLAY BOARD DISPLAY DESCRIPTION 3.7SYNTHESIZER CIRCUIT DESCRIPTION (UHF MODELS) UHF SYNTHESIZER DESCRIPTION 4-3Figure Diagram Block RF Models) (UHF DESCRIPTION SYNTHESIZER UHF DESCRIPTION CIRCUIT Page Page Figure 3-5Synthesizer Chip U804 Block Diagram 3.8RECEIVER CIRCUIT DESCRIPTION (UHF MODELS) UHF RECEIVER DESCRIPTION Figure 3-6Limiter/Detector U201 Block Diagram UHF TRANSMITTER DESCRIPTION 3.9TRANSMITTER CIRCUIT DESCRIPTION (UHF MODELS) Page Page 800/900 MHz SYNTHESIZER DESCRIPTION 3.10SYNTHESIZER CIRCUIT DESCRIPTION (800/900 MHz MODELS) 7-3Figure Models) MHz (800/900 DESCRIPTION SYNTHESIZER MHz 800/900 Normal Mode Talk-AroundMode Page Page Page 800/900 MHz RECEIVER DESCRIPTION 800/900 MHz TRANSMITTER DESCRIPTION 3.12TRANSMITTER CIRCUIT DESCRIPTION (800/900 MHz MODELS) Page Page Page SECTION 4 SERVICING American EIA Standard Japanese EIA Standard (pF) Color Multi Figure 4-1Simplified Synthesizer Block Diagram 4.3 SYNTHESIZER TROUBLESHOOTING Table 4-2SMD Inductor Identification Mode Supply Voltage Output Level Control Voltage VCO RF In (pin 6) Overall Div No. (K) = VCO freq ÷ “A” Divide No “N” Divide No Fractional-NDiv No. = (Fraction K) x 4.4RECEIVER SERVICING SECTION 5 PARTS LIST FRONT PANEL ASSEMBLY AND MECHANICAL PARTS FRONT PANEL ASSEMBLY AND MECHANICAL PARTS (CONT’D) UHF RF AND PA BOARDS UHF RF AND PA BOARDS (CONT ’D) Page Page Page Page Page Page Page Page Page Page Page Page Page 800/900 MHZ RF AND PA BOARDS 800/900 MHz RF AND PA BOARDS (CONT ’D) Page Page Page Page Page AUDIO/LOGIC BOARD (ALL MODELS) AUDIO/LOGIC BOARD (CONT’D) Page Page Page 9800-SERIESRADIO MOUNTING KIT 9800-SERIESREMOTE MOUNTING KIT DC POWER CABLE AND HARDWARE KIT PART NO. 023-9800-410(10 Ft) PART NO. 023-9800-422(22 Ft) FRONT PANEL EXPLODED VIEW FRONT AND TOP MECHANICAL PARTS BOTTOM MECHANICAL PARTS REMOTE TRANSCEIVER MECHANICAL PARTS REMOTE CONTROL UNIT MECHANICAL PARTS SECTION 6 SCHEMATIC DIAGRAMS AND COMPONENT LAYOUTS TRANSISTOR AND DIODE BASING DIAGRAMS Page Page CAUTION: INTERFACE BOARD LAYOUT INTERCONNECT SCHEMATIC DISPLAY BOARD TOP VIEW DISPLAY BOARD BOTTOM VIEW PROGRAMMING CABLE (P.N. 597-2002-200) RPI (P.N. 023-9800-000)BOARD LAYOUT RPI (P.N. 023-9800-000)SCHEMATIC RF BOARD COMPONENT LOCATOR GUIDE (UHF) UHF RF BOARD COMPONENT LOCATOR GUIDE (CONT’D) ’D) RF BOARD COMPONENT LOCATOR GUIDE (800/900 MHZ) Page Page Page Page RF BOARD SCHEMATIC (REVISED 430-470MHZ) PA BOARD SCHEMATIC (25W, 430-470MHZ)