EFJohnson 7780 service manual Removing RF Unit, Removing Logic Unit

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GENERAL INFORMATION

LOCK

UNLOCK

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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Contents 7780 Page Page Table of Contents Table of Contents CONT’D List of Figures List of TablesScope of Manual Equipment Description General InformationFactory Customer Service AccessoriesPart Number Breakdown Transceiver IdentificationAccessory AccessoriesToll-Free 800 Factory ReturnsInternet Home Intrinsically Safe Information Replacement PartsDefinitions Possible Ignition Sources Temperature Code T3CIntrinsically Safe and Nonincendive Ratings Classification of Hazardous Areas and AtmospheresMaterial Classification Accessing PC BoardsTypical Hazard Group Class Area ClassificationRemoving Logic Unit Removing RF UnitGeneral SpecificationsTransceiver Operation FeaturesControls and Display Low-Battery Indicator Amber TX Indicator Red Indicates when the transmitter is keyedFront Panel Keys Full Keypad Model DisplayDisplay Option Switches Turning Power on and Setting VolumeGeneral Operation BacklightFunction Conv Option Switch FunctionsSee Scanning Tone ENABLE/DISABLEConventional 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 ScanningPriority Channel Sampling Standard Conventional Calls DTMF/ANI SignalingViewing Unit ID SMARTNET/SMARTZONE FeaturesStandard Group Calls Enhanced Private Conversation CallsTransceiver 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 DescriptionStarting and Exiting Connecting RPI to Computer and TransceiverProgramming File Types Help FilesProgramming Procedure Screen Pop-Up Buttons and File Size IndicatorFile Size Indication Creating and Displaying SystemsMenu Bar Menu CommandsDownload Menu Upload Menu Radio Type MenuSystems Menu Window MenuRADIO-WIDE Parameter Screens DefaultsBand ZonesRadio-Wide Scan List Screen Radio Wide Scan ListModify List Screen Assign Function ButtonsRADIO-WIDE SMARTNET/SMARTZONE Screen RADIO-WIDE Conventional ScreenFull Spectrum CC Scan Hot DtmfRADIO-WIDE Portable Options Screen Adjustable ParametersProgramming Conventional Systems and Channels Conventional System General ScreenConventional System Modify Scan List Screen TimersKeypad Editing Scan List ButtonSetting UP Conventional Channels Scan TimersPriority Channel Selection Selected Channel Conventional Channel Screen ParametersSignaling Transmit PowerChannel Type Tx Time-OutTime-Out Timer Restricted AccessISW Delay Time Splinter ChannelsSMARTNET/SMARTZONE System Phone Interconnect Screen SMARTNET/SMARTZONE System Other ID’S ScreenPhone Interconnect Private CallEmergency Alarm SMARTNET/SMARTZONE System Emergency Settings ScreenSMARTNET/SMARTZONE System Talk Groups Screen Failsoft ChannelTrunking Phone List Screen SMARTNET/SMARTZONE System Lists ScreensMessage Aliasing Screen Control Channels Screen Announcement Groups ScreenTrunking Call List Screen Status Aliasing Screen Setting UP SMARTNET/SMART- Zone ChannelsSMARTNET/SMARTZONE Channel Screen Parameters Other Screen Parameters SMARTNET/SmartZone Channel ScreenRecommended Tone Call Guard Codes Freq Call Guard CTCSS/DCS Codes and TonesMHz Channels MHz Channels MHz Channels MHz Channels MHz Channels MHz Channels Power Switching Power Switching and RegulationCircuit Description Synthesizer DescriptionSynthesizer 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 Q8Receive Audio Processing Control Logic and DisplayPin Port Name Input or Description Active High Output Microprocessor IC306 Pin DescriptionsHvfulswlrq Receive and Transmit Data Processing Audio Amplifier IC104-IC106Receive Data FILTER/DETECTOR IC102A/B, IC107A/B Transmit Audio Processing Transmit Data Filter IC206B/ IC206ASmartnet Data Processing LOW-PASS Filter IC205A/BBattery Pack Battery Pack and Charger InformationPower Setting Operating Time Function Fahrenheit CelsiusBattery Pack and Charger Information Test Setup Alignment Procedure and Performance TestsMm/3/32 Mm/1/8 Phone Jack Tune Software HqhudoMain Pctune Screen Preliminary SetupTransmit Power Adjustment Screen Transmit Frequency and PowerHigh Power Level = 3.0 watts Low Power Level = 1.0 watt Modulation BalanceRssi Adjust Squelch AdjustAudio Deviation Data DeviationReceiver Performance Tests Performance TestsTransmitter Performance Tests Power OutputTransmit Frequency Transmit ModulationThis page intentionally left blank Display Assembly Parts ListChassis Parts Ref No DescriptionDisplay Assembly KEY AssemblyKEY Assembly If AssemblyIf Assembly RF Unit PLL AssemblyRF Unit NJM2904V-TE1 IC RF Unit Logic Unit Logic Unit TDA7233D IC Logic Unit 200K ERJ3GE MP35 MP18 MP25 EP2 KEY Front PanelEP1 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 ViewRF Unit Transceiver Block DiagramMIC RF Board TOP ViewIf AMP RF Board SchematicHD1 Logic Board TOP ViewReceive Audio Processing Logic Board SchematicGND KEYR3 KEYR2 KEYR1 KEYR0 KEYS3 KEYS2 KEYS1 KEYS0 GND Display Board Bottom ViewDS3 DS4 DS5 Display Board SchematicKEY Board Back View KEY Board Front ViewS S R R R R KEY Board SchematicScan HC2 HC7 HC8 HC3 Schematic Diagrams and Component Layouts