Removing RF Unit, Removing Logic Unit | EFJohnson 7780 specs

GENERAL INFORMATION

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1.11.4 REMOVING RF UNIT

1.Remove the five screws attaching the shield to the PC board.

2.Remove the two screws securing the RF power module to the chassis. Then remove the four stand- offs attaching the RF board to the chassis.

3.Unsolder the antenna connector from the PC board by removing the solder at the locations shown in the following illustration.

SOLDER

WIRE IN	ANTENNA
PC BD	CONNECTOR

4.Remove the PC board by lifting it upward. The RF- to-logic board connector under the IF board must unplug, so some resistance may be encountered. Do not pull on the IF or PLL board assemblies because they can be easily damaged.

1.11.5 REMOVING LOGIC UNIT

1.Remove the top panel knobs. Then remove the spanner nuts on the quick select and on-off/volume switches. Remove the plastic top panel.

2.Unplug the flex cables from the front panel, acces- sory connector, and PTT switch as described in Section 1.11.3.

3.Unsolder the DC power flex circuit attached to the logic unit near the accessory flex circuit connector.

4.Remove the four screws attaching the logic unit to the chassis.

5.Remove the logic unit by carefully lifting it outward. The RF-to-logic board connector under the IF board must unplug, so some resistance may be encountered. There is a pry hole (indicated by an arrow) on the lower left edge of the PC board.

	November 1999
1-7	Part No. 001-7780-500

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EFJohnson 7780 service manual Removing RF Unit, Removing Logic Unit

Contents

7780 Page Page Table of Contents Table of Contents CONT’D List of Figures List of Tables Scope of Manual Equipment Description General Information Factory Customer Service AccessoriesPart Number Breakdown Transceiver Identification Accessory AccessoriesToll-Free 800 Factory Returns Internet Home Intrinsically Safe Information Replacement PartsDefinitions Possible Ignition Sources Temperature Code T3CIntrinsically Safe and Nonincendive Ratings Classification of Hazardous Areas and Atmospheres Material Classification Accessing PC BoardsTypical Hazard Group Class Area Classification Removing Logic Unit Removing RF Unit General Specifications Transceiver Operation FeaturesControls and Display Low-Battery Indicator Amber TX Indicator Red Indicates when the transmitter is keyed Front Panel Keys Full Keypad Model DisplayDisplay Option Switches Turning Power on and Setting VolumeGeneral Operation Backlight Function Conv Option Switch FunctionsSee Scanning Tone ENABLE/DISABLE Conventional and SMARTNET/ Smartzone Operation Display Mode Selection Conventional FeaturesMonitoring Before Transmitting Busy Channel Lockout Monitor ModeCall Guard Squelch Conversation Timer Penalty TimerPower Output Select Conventional Mode Scanning Priority Channel Sampling Standard Conventional Calls DTMF/ANI Signaling Viewing Unit ID SMARTNET/SMARTZONE FeaturesStandard Group Calls Enhanced Private Conversation Calls Transceiver Operation Private Conversation II Calls Telephone Calls Call Alert Messaging Emergency Alarm and CallSending Status Conditions SMARTNET/SMARTZONE Scanning Failsoft OperationDynamic Regrouping Supervisory Tones Menu Description Keypad ProgrammingZone Change Parameter System Parameters Channel Change ParameterChannel Parameters Pctrunk Software Installation Programming SetupTransceiver Programming Computer Description Starting and Exiting Connecting RPI to Computer and TransceiverProgramming File Types Help Files Programming Procedure Screen Pop-Up Buttons and File Size IndicatorFile Size Indication Creating and Displaying Systems Menu Bar Menu Commands Download Menu Upload Menu Radio Type MenuSystems Menu Window Menu RADIO-WIDE Parameter Screens DefaultsBand Zones Radio-Wide Scan List Screen Radio Wide Scan ListModify List Screen Assign Function Buttons RADIO-WIDE SMARTNET/SMARTZONE Screen RADIO-WIDE Conventional ScreenFull Spectrum CC Scan Hot Dtmf RADIO-WIDE Portable Options Screen Adjustable ParametersProgramming Conventional Systems and Channels Conventional System General Screen Conventional System Modify Scan List Screen TimersKeypad Editing Scan List Button Setting UP Conventional Channels Scan TimersPriority Channel Selection Selected Channel Conventional Channel Screen Parameters Signaling Transmit PowerChannel Type Tx Time-Out Time-Out Timer Restricted AccessISW Delay Time Splinter Channels SMARTNET/SMARTZONE System Phone Interconnect Screen SMARTNET/SMARTZONE System Other ID’S ScreenPhone Interconnect Private Call Emergency Alarm SMARTNET/SMARTZONE System Emergency Settings ScreenSMARTNET/SMARTZONE System Talk Groups Screen Failsoft Channel Trunking Phone List Screen SMARTNET/SMARTZONE System Lists ScreensMessage Aliasing Screen Control Channels Screen Announcement Groups Screen Trunking Call List Screen Status Aliasing Screen Setting UP SMARTNET/SMART- Zone ChannelsSMARTNET/SMARTZONE Channel Screen Parameters Other Screen Parameters SMARTNET/SmartZone Channel Screen Recommended Tone Call Guard Codes Freq Call Guard CTCSS/DCS Codes and Tones MHz Channels MHz Channels MHz Channels MHz Channels MHz Channels MHz Channels Power Switching Power Switching and RegulationCircuit Description Synthesizer Description Synthesizer Chip IC1 VCO and Tcxo ModulationCharge Pump Q1, Q2, Loop Filter RF Amplifier Q1, First Mixer Q2 Receiver Circuit DescriptionIf Amplifier Q2, LIMITER/DETECTOR IC3 Squelch Circuit IC4A/B, IC5A Antenna Switch and LOW-PASS FilterTransmitter Description Amplifier Q9, Driver Q8 Receive Audio Processing Control Logic and Display Pin Port Name Input or Description Active High Output Microprocessor IC306 Pin Descriptions Hvfulswlrq Receive and Transmit Data Processing Audio Amplifier IC104-IC106Receive Data FILTER/DETECTOR IC102A/B, IC107A/B Transmit Audio Processing Transmit Data Filter IC206B/ IC206A Smartnet Data Processing LOW-PASS Filter IC205A/B Battery Pack Battery Pack and Charger InformationPower Setting Operating Time Function Fahrenheit Celsius Battery Pack and Charger Information Test Setup Alignment Procedure and Performance Tests Mm/3/32 Mm/1/8 Phone Jack Tune Software Hqhudo Main Pctune Screen Preliminary Setup Transmit Power Adjustment Screen Transmit Frequency and PowerHigh Power Level = 3.0 watts Low Power Level = 1.0 watt Modulation Balance Rssi Adjust Squelch AdjustAudio Deviation Data Deviation Receiver Performance Tests Performance Tests Transmitter Performance Tests Power OutputTransmit Frequency Transmit Modulation This page intentionally left blank Display Assembly Parts ListChassis Parts Ref No Description Display Assembly KEY Assembly KEY Assembly If AssemblyIf Assembly RF Unit PLL Assembly RF Unit NJM2904V-TE1 IC RF Unit Logic Unit Logic Unit TDA7233D IC Logic Unit 200K ERJ3GE MP35 MP18 MP25 EP2 KEY Front Panel EP1 MP32 MP33 MP27 MP34 MP28 MP29 MP23 MP22 MP30 MP24 MP26 MP18 PLL Board TOP View Schematic Diagrams and Component LayoutsPLL Board Bottom View If Board Bottom View If Board TOP View RF Unit Transceiver Block Diagram MIC RF Board TOP View If AMP RF Board Schematic HD1 Logic Board TOP View Receive Audio Processing Logic Board Schematic GND KEYR3 KEYR2 KEYR1 KEYR0 KEYS3 KEYS2 KEYS1 KEYS0 GND Display Board Bottom View DS3 DS4 DS5 Display Board Schematic KEY Board Back View KEY Board Front View S S R R R R KEY Board Schematic Scan HC2 HC7 HC8 HC3 Schematic Diagrams and Component Layouts