EFJohnson 764X, 761X service manual Channel Scan

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CODE

OPERATION

3.5.15 SCAN LIST PROGRAMMING

Pressing the TAG key changes the scan list sta- tus of the current channel. Refer to the scan list description in Section 3.6.2 for more information.

3.5.16 TALK-AROUND SELECT

The talk-around mode causes transmissions to occur on the receive frequency to permit direct mobile-to-mobile communication when a repeater is being used. The talk-around mode is turned on and off by pressing the TA key. Either “AR ON” or “AR

OF” is briefly displayed to indicate the current mode. Changing the channel or turning power off causes talk- around to revert to the off condition.

3.5.17 2-TONE CALLING FEATURES

If the optional 2-tone signaling option is used, pressing the CALL key transmits the 2-tone codes on

the selected channel or on a non-busy channel if pressed while scanning.

3.5.18 5-TONE CALLING FEATURES

If the optional 5-tone signaling option is used, the following keys may be programmed to control various functions.

CALL CAL A CAL B - Transmit the 5-tone call. Depending on your signaling system, call transmission may be necessary before you call another station. The CAL A and CAL B keys may be programmed when selective Individual/Group calls are used.

TX CH - Selects the 5-tone code to be transmitted. To change the contents of the station code, push and hold

this key and then press the keys.

- Selects the transmit code directory.

MR CH - Recalls last five codes received. Press and

hold to erase all codes. To scroll, press .

3.5.19 WIDE/NARROW BAND SELECT

Pressing the W/N key switches the receiver

between narrowband and wideband operation. The

display briefly indicates “WIDE” or “NARROW” to indicate the current mode. Each channel can also be programmed for wide or narrow band operation, and this switch toggles that setting. However, the change is only temporary because the programmed condition is reselected if the channel is changed or power is cycled.

3.6 CHANNEL SCAN

3.6.1 INTRODUCTION

The channel scan feature monitors the channels in the current scan list. When a message is detected that the transceiver is programmed to receive, scanning stops and the message is received. Shortly after the message is complete, scanning resumes (after the resume timer counts down). The selected channel changes to that of the call.

If the microphone is taken off-hook or the trans- mitter is keyed while scanning, scanning resumes when the auto reset timer selected for the channel counts down. Scanning does restart if this timer is dis- abled or if the Scan A key is programmed with power- on scan disabled (see Tables 4-2and 4-5).

Scanning is turned on and off by the SCAN key. The transceiver also may be programmed so that scan- ning automatically turns on whenever power is turned on or the microphone is placed on-hook. The micro- phone must be on-hook for scanning to occur.

The decimal point in the display flashes when the scan mode is enabled. Then when scanning is actually occurring, either the scan list identification (see next section) or the rapidly cycling channel identification is displayed as the channels are scanned. Programming determines which occurs (see Table 4-5).

3.6.2 SCAN LISTS

Up to five scan lists can be selected by pressing and holding the SCAN key until the scan list identifi-

cation appears and then pressing the keys. Press the SCAN key again to exit this mode (this also

occurs automatically in about 30 seconds) and again to enable scanning (if desired).

 

November 1998

3-7

Part No. 001-7600-001

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Contents 761x VHF 764x UHF Conventional Mobile Conventional FM TWO-WAY Radio Table of Contents Table of Contents CONT’D Schematic Diagrams and Component Layouts General Information 75xx Accessories AccessoryToll-Free 800 Factory ReturnsReplacement Parts Internet HomeThis page intentionally left blank VHF and 7640 UHF Mobile Specifications GeneralGeneral Information Installation and Disassembly Transceiver InstallationInstalling Mounting Bracket Installing Microphone HangerPower Cable Installation Cable InstallationPower Cable Fuses Changing 20-Ampere Power Cable FusesUsing AN External Speaker Accessory Cable InstallationTransceiver Disassembly Removing PC BoardRemove shield E 2-TONE/5-TONE Module Installation Installation ProcedureSetting 5-Tone Deviation 2 2-TONE ProgrammingInstallation and Disassembly Features OperationControls and Display Transceiver Back PanelBasic Operation Direct Selection The F1-F4 Receiving and Placing Calls TIME-OUT Timer Programmable FunctionsOption Key Programmable Functions Function Key Label Description Section NoMonitor Mode Select Output Power SelectCall Guard Tone Select Channel SelectChannel Scan Priority Channel Sampling Programming Setup Section ProgrammingProgramming Cables Programming SoftwareStarting the Program Special Keys and FunctionsMenu Flow File MenuScreen Menu Program MenuPrint Menu Model MenuSetup Menu Memory Channel Screen Description LMR ModelsParameter Description Bank Select Timer Ch AtrFrequency Rx/TxAuto Reset LockoutScan ToneKey and Display Assign Screen Description Key DescriptionKey Description Label RF Power Dtmf Autodial Screen DescriptionSelection Bank/FreeContinuous Tone Screen Description Scan Function Screen DescriptionParameter Description Stop Timer 2-Tone Code Channel Screen DescriptionResume Auto CHEXO Timer Timer Auto TxAuto Tx StunCommon Screen Description Expert Screen Description Unique PMR European Screens Unique PMR ScreensCloning Programming ONE Transceiver with Another Memory Channel Screen PMR Models This page intentionally left blank VHF 7610 Circuit Description VHF Receiver CircuitAudio Amplifier Circuit Receiver Mute CircuitPower Amplifier Module VHF Transmitter CircuitMicrophone Amplifier Circuit Modulation CircuitAPC Circuit VHF PLL CircuitPLL Circuit VHF IC PIN Descriptions Line DescriptionPin Port Description VHF I/O Expander IC5 Main Unit PinVHF Port Expander IC11 Main Unit Pin Port Description NameUHF 7640 Circuit Description UHF Receiver CircuitSecond if System IC1 UHF UHF Transmitter Circuit PLL Circuit UHF UHF PLL CircuitUHF Power Supply UHF CPU IC1 Port AllocationUHF I/O Expander IC12 Main Unit UHF Port Expander IC13 Main UnitAdjustment Procedure Test SetupSuggested Test Equipment Equipment Grade and RangeTest Channels Test CableCOMPUTER-AIDED Tuning VHF Test FrequenciesUHF Test Frequencies VHF Adjustments VHF AdjustmentsPreliminary Setup PLL Adjustment VHF ModelsVHF Adjustments CONT’D Output Power AdjustFM Deviation Adjust Dtcs Waveform Adjust Receiver Adjustments VHF ModelsBandpass Filter Adjust Squelch AdjustBeep Tone Level Adjustment Beep Tone LevelUHF Adjustments PLL Adjustment UHF ModelsTransmitter Adjustments UHF Models UHF Adjustments CONT’D UHF Adjustment PointsUHF Adjustments CONT’D Receiver Adjustments UHF Models Parts List Æçìíýõ9+ôý0$,1ý81,7Íäç HUDPLFý&ìçíåý-%ýì+ýìíë.ð7ð$ Íëëðêäíçðíçí Íäæ Ìää HUDPLFý&ìçíåý-%ýì&ýìíé.7ð1 Íëëðêäíçðçìé Ëíí Ëäí HUDPLFý&ìçíåý-%ýìýìíê.ð7ð$ Íëëðêäíçðíçê Ëäì RLOý0/ìçíå$ýì5í.ð7 Íëëðêäíçðçèç 03ì Ýìäëëý9&2ýFDVH 5íéé 5HVý5-ê*-ýìííý9ýõìíýRKPô Íëëðêäíçðìêå 5íéè 5ìèé 5HVý5-ê*-ýìíéý9ýõìííýNýRKPô Æçéíýõ8+ôý0$,1ý81,7 Íêì HUDPLFý&ìçíåý-%ýì+ýìíë.ð7ð$ Íëëðêäíçðíçí Íêë Íäé HUDPLFý+0çí6-ý&+ýíêíýèíí9ý Õéäíðèìëý0+ô Ìèì 5HIý1Rï Êëç Íëëðêäíçðäèë 4éì 7UDQVLVWRUý7&êçê.ý7ìéæ 5íæé 5ìçå 5HVý5-ê*-ýìíéý9ýõìííýNýRKPô 5217ý81,7 Õ9+ý$1ý8+ý02/6ô =HQHUý0$åíèìð0ýõ7ô Æçìíýõ9+ôý&+$66,6ý3$576 VHF 7610 Exploded View Front UnitUHF 7640 Exploded View Schematic Diagrams and Component Layouts VHF 7610 Block DiagramMain Unit Front UnitVHF 7610 Transistor Basing Diagrams Foldout → VHF 7610 Main Board TOP View VHF 7610 Main Board Schematic VHF Main UnitUHF 7640 Block Diagram UHF 7640 Main Board Bottom View UHF 7640 Main Board TOP View J4 T o O p tion al Un itUHF 7640 Main Board Schematic VHF/UHF Front Unit Board TOP View VHF/UHF Front Unit Board Bottom ViewVHF/UHF Front Unit Schematic UHF 7640 Transistor Basing Diagrams