SECTION 1 GENERAL INFORMATION 1.1 SCOPE OF MANUAL This service manual contains operation, installa- tion, programming, alignment, and service information for the EFJohnson® 7610 and 7640 mobile transceiv- ers. 1.2 TRANSCEIVER DESCRIPTION 1.2.1 GENERAL The 7600-series mobile transceivers operate on conventional (non-trunked) channels.
NOTE: Emergency 24-hour technical support is also available at the 800 and preceding numbers during off hours, holidays, and weekends. When your call is answered at EFJohnson, you will hear a brief message informing you of numbers that can be entered to reach various departments. This number may be entered during or after the message using a tone-type telephone.
P.O. Box 1249 Waseca, MN 56093-0514 1.10 INTERNET HOME PAGE EFJohnson has a site on the World Wide Web that can be accessed for information on the company and such things as products, systems, and regulations. The address is http://www.efjohnson.com.
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7610 (VHF) AND 7640 (UHF) MOBILE SPECIFICATIONS The following are general specifications intended for use in testing and servicing this transceiver. For current advertised specifications, refer to the specification sheet available from your sales representative. Values are typical and are subject to change without notice. Frequency Range Operating Modes Channels...
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GENERAL INFORMATION NOTES November 1998 Part No. 001-7600-001...
Section 4. Transceivers normally contain UHF-Type Ant Jack 10-Ft. Power Cable Black (–) Optional External Speaker P .N. 250-0151-010 20A Fuses Figure 2-1 Installation Components factory test channels and other test parameters when they are shipped. The included labels should be attached to the option keys to indicate the function.
INSTALLATION AND DISASSEMBLY Figure 2-2 Mounting Bracket Installation WARNING • Do not mount the transceiver where it may inter- fere with the operation of vehicle controls. • Do not mount the transceiver where the user can- not easily reach the controls and view the display.
2.4 USING AN EXTERNAL SPEAKER An external speaker can be plugged into the external speaker jack on the back of the transceiver. This speaker should have an impedance of 4-8 ohms and a power handling capability of at least 3.5 watts.
INSTALLATION AND DISASSEMBLY 2.6 TRANSCEIVER DISASSEMBLY Removing Bottom Cover and Front Panel 1. Remove the bottom cover by removing four screws (A) as shown in Figure 2-4. 2. Remove the front panel by removing two screws (B). Figure 2-4 Cover and Front Panel Removal Removing PC Board 3.
2.7 2-TONE/5-TONE MODULE INSTALLATION 2.7.1 INSTALLATION PROCEDURE 1. Turn power off and disconnect the power cable. 2. Remove the bottom cover by removing the four screws (A) shown in Figure 2-5. 3. Install the module as shown in Figure 2-7. The included foam pad is not used with this transceiver.
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INSTALLATION AND DISASSEMBLY 1. Monitor the transmit signal with a communications monitor. Set it for HPF = Off, LPF = 20 kHz, De- emphasis = Off, and Level = (P-P)/2. 2. Select a channel near the center of the band and turn a long tone on (see preceding “NOTE”) by pressing the appropriate front panel key.
Volume Volume Transmit Down Indicator Scan List Microphone Indicator Connector * The Channel Up/Down switches can also be programmed for other functions. 3.1 FEATURES • Up to 32 channels programmable • Multi-tone (CTCSS) and/or Multi-code (CDCSS) Call Guard® squelch programmable •...
8 VDC. ) - Adjust the vol- 3.2.3 BACK PANEL External Speaker Jack - Miniature phone jack for connecting an optional 4-8 ohm external speaker. The internal speaker is automatically disabled when a speaker is plugged into this jack.
2. Press the F4 option key to select the squelch adjust mode indicated by “SQ xx”. 3. Press the down the speaker (adjust the volume if necessary). Then press the up “SQ xx” number indicates the relative squelch level).
OPERATION 3.3.7 BANK SELECT Two banks of up to 16 channels each can be pro- grammed. Only the channels in the current bank are then selectable. This would allow, for example, groups of channels to be programmed for operation in differ- ent cities.
• Note if the busy indicator ( is being displayed. If it is not, the channel is not busy and a message can be transmitted. • Taking the microphone off-hook disables coded squelch control if it is programmed for the monitor function.
OPERATION 3.5.5 CALL GUARD TONE SELECT If the transceiver has a TONE Guard (CTCSS) tone can be selected. This allows calls to be placed to different mobiles or groups of mobiles and received on different groups than is normal for the channel.
3.5.15 SCAN LIST PROGRAMMING Pressing the 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.
OPERATION The scan lists are user programmable if the key is available. Pressing this key changes the status of the displayed channel in the current scan list only. The display indicates “SC ON” if the channel was just added to the scan list and “SC OF” if it was just deleted.
Programming Cable (Includes Level Convert. Circuit) P .N. 585-7500-031 4.1 GENERAL 4.1.1 PROGRAMMING SETUP The following items are required to program this transceiver. The part numbers of the programming cable and software are shown in Table 1-1. A printer is also recommended for making a hard copy record of the information programmed into the transceiver.
PROGRAMMING on the disk called ADJ. The use of this program is described in Section 5. These are DOS programs, so Windows® 3.x, 95, or NT are not required to run them. If the program does not run properly in Windows, run it in the DOS mode.
4.4.3 SCREEN MENU LMR (U.S.) Format NOTE: The Screen menu for PMR (European) models is slightly different than the LMR version shown above. Refer to Section 4.5 for more information on PMR models. Memory Channel - Displays the screen shown in Table 4-1 which is used to program channel parame- ters such as frequency, Call Guard (CTCSS/DCTS) coding, and power output.
PROGRAMMING in the Screen menu (see Section 4.4.3), Memory Channel screen (see Table 4-1), and DTMF Autodial screen (see Table 4-3). PMR - Selects PMR (European) models. Selecting this model displays unique parameters for program- ming a 5-tone option. As with the LMR selection, unique parameters are displayed in the Screen menu and Memory Channel and DTMF Autodial screens.
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Table 4-1 Memory Channel Screen Description (LMR Models) (Continued) Parameter Ch Atr Press (Enter) to display the menu which selects one of the following choices: (Channel Attribute) A: Priority A - The channel is selected when the Prio A key is pressed, and it is monitored during priority scan. In addition, the microphone hanger can be programmed so that this channel is automatically selected when- ever an off-hook condition occurs (see Table 4-2).
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PROGRAMMING Table 4-1 Memory Channel Screen Description (LMR Models) (Continued) Parameter RF PWR Programs the RF power output for the channel (High, Low1, Low2). This setting can be temporarily or perma- nently overridden by the HIGH, LOW1, or LOW2 power option switch if it is programmed (see Table 4-2). Lockout Transmit Disable On Busy.
Table 4-2 Key and Display Assign Screen Description and F1-F4 option keys can be programmed for the following functions. Press the (Enter) key and then PgUp/PgDn to display and then select the desired function. Parameter Label Null No function (key disabled). CH Up CH UP Scroll up or down through the programmed channels.
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PROGRAMMING Table 4-2 Key and Display Assign Screen Description (Continued) Parameter Label RF ATT Toggles the receive attenuate function on and off (see Section 3.5.13). Lock LOCK Locks/unlocks all programmable keys except CALL, MONI, and EMER to prevent them from being accidentally pressed (see Section 3.5.9).
Table 4-2 Key and Display Assign Screen Description (Continued) Parameter Light Enables or disables the display and key backlight. This programming can be overridden by the power-on menu (see Section 3.3.4) or LITE key (see Section 3.3.9). The “Auto” configuration allows it to be controlled by pin 1 of the DB9 connector on the optional accessory cable.
PROGRAMMING Table 4-4 Continuous Tone Screen Description The continuous tones programmed in this screen are selected by pressing the C.Tone CH Ent function key (see Table 4-2) and then pressing the up/down and received on the current channel. To transmit or receive using the codes programmed for the channel in the channel screen (see Table 4-1), select “TON--M”...
Table 4-5 Scan Function Screen Description (Continued) Parameter Stop Timer When Mode 2 or 3 above is programmed (priority scanning), this sets how often in seconds the priority channel is checked while receiving a message on some other channel. Resume This sets the scan resume delay in seconds.
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PROGRAMMING Table 4-6 2-Tone Code Channel Screen Description (Continued) Parameter Beep Emits (or turns off) the following beeps when receiving a matched 2-tone: Null - Beep emission (or non-emission) is retained even when receiving a matched 2-tone. Off - Repeater beep emission is turned off. Pi (Single) - One high beep once.
Table 4-7 Common Screen Description Parameter User Programs the password that must be entered at power on if the following “PWR ON Password” parameter is Password “On” or to cancel the “STUN” condition described in Table 4-6. Any four-digit number from 0000-9999 can be programmed.
PROGRAMMING Table 4-7 Common Screen Description (Continued) Parameter Power On This turns the password function on and off. When it is turned on, “PWoRd” is displayed when power is turned Password on and a four-digit password must be entered to enable the transceiver (see Section 3.3.2). The password is pro- grammed in “User Password”...
Table 4-8 Expert Screen Description (Continued) Parameter Emer Sw Sets the period in seconds that the Emergency function key must be pressed to activate the emergency function. On Timer An emergency call is initiated by pressing the Emergency key for longer than this time. Emer Sw Sets the period in seconds that the Emergency function switch must be pressed to cancel an emergency call.
PROGRAMMING The following screens selected in the preceding Screen menu are unique to PMR models. Refer to on- line help for information on parameters in these screens. Rx Code Channel - This screen is shown below and it programs the receive 5-tone code information. Tx Code Channel - This screen is shown below and it programs the transmit 5-tone code information.
4. Connect the master transceiver to the slave (target) transceiver by plugging the cloning cable into the microphone jack of each. 5. Turn the slave transceiver on. Then momentarily press the POWER switch of the master transceiver to begin the data transfer. Figure 4-2 Memory Channel Screen (PMR Models) 6.
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SECTION 5A VHF (7610) CIRCUIT DESCRIPTION NOTE: A VHF transceiver block diagram is located on page 8-1. 5.1 VHF RECEIVER CIRCUIT 5.1.1 ANTENNA SWITCHING CIRCUIT The antenna switching circuit functions as a low- pass filter while receiving and a resonator circuit while transmitting.
5.1.5 AUDIO AMPLIFIER CIRCUIT The AF (audio frequency) amplifier circuit pro- vides drive to the speaker (a block diagram is shown in Figure 5-2). The audio signal from IC3, pin 9 is applied to AF amplifier IC7A and then fed to pin 1 of AF switching circuit IC4.
Part of the AF signal from pin 9 of FM IF circuit IC3 is applied to pin 24 of level controller IC5. This device allows the CPU to control the squelch threshold level. The level-controlled output signal on pin 23 is applied to IC3, pin 8 which is the input of an internal filter (see Figure 5-1).
VHF (7610) CIRCUIT DESCRIPTION 5.2.5 APC CIRCUIT The APC (Automatic Power Control) circuit pro- tects the power amplifier from damage caused by a mismatched antenna load, and provides a stable power output. Detector D2 detects forward signals, and D1 detects reverse signals. The combined voltage is at minimum level when a matched antenna load of 50 ohms is present and then increases as it becomes mis- matched.
The phase detector determines the phase differ- ence between these signals and then produces output pulses on pin 8 which are filtered by the loop filter. This filter consists of R43-R45, C60, and C61. The output of this filter is the DC control voltage applied to the VCO.
VHF (7610) CIRCUIT DESCRIPTION Port Description Name Outputs control signal for beep mute cir- cuit Q10. High = Beep muted. CTDA0- Output port for CTCSS/DTCS signals. CTDA2 HANG Input port for the microphone hanger detection signal. Low = Microphone on hook.
SECTION 5B UHF (7640) CIRCUIT DESCRIPTION NOTE: The UHF transceiver block diagram is located on page 8-6. 5.5 UHF RECEIVER CIRCUIT 5.5.1 ANTENNA SWITCHING CIRCUIT The antenna switching circuit functions as a low- pass filter while receiving and a resonator circuit while transmitting.
5.5.5 AUDIO AMPLIFIER CIRCUIT The AF (audio frequency) amplifier circuit pro- vides drive to the speaker (see block diagram in Figure 5-5). The audio signal from IC1, pin 9 is applied to AF amplifier IC7b and then fed to high-pass filter IC6c/ IC6d.
Part of the AF signal from pin 9 of FM IF circuit IC1 is applied to pin 24 of level controller IC12. This device allows the CPU to control the squelch threshold level. The level-controlled output signal on pin 23 is applied to IC1, pin 8 which is the input of an internal filter (see Figure 5-4).
UHF (7640) CIRCUIT DESCRIPTION 5.6.5 APC CIRCUIT The APC (Automatic Power Control) circuit pro- tects the power amplifier from damage caused by a mismatched antenna load, and provides a stable power output. One diode in D1 detects forward signals and the other detects reverse signals.
The phase detector determines the phase differ- ence between these signals and then produces output pulses on pin 8 which are filtered by the loop filter. This filter consists of Q34, R180, R181, and C202- C204. The output of this filter is the DC control volt- age applied to the VCO.
UHF (7640) CIRCUIT DESCRIPTION Port Description Name Outputs control signal for beep mute cir- cuit Q10. High = Beep muted. CTDA0- Output port for CTCSS/DTCS signals. CTDA2 HANG Input port for the microphone hanger detection signal. Low = Microphone on hook.
External Speaker ±1 ppm or better 100 mV or better ADJUSTMENT PROCEDURE Frequency Monitor 13.6 Volt, 17A Power Supply 4.0 Ohm Speaker Load Grade and Range Freq range DC-520 MHz Measuring range 0 to ±10 kHz Freq range 67-3000 Hz...
ADJUSTMENT PROCEDURE Supply Voltage Internal Temp PLL Lock Voltage RSSI DTCS Bal Level Squelch Level Selected Channel Info RF Power Output FM Deviation DTCS Balance Reference Frequency NOTE: The above values for the various settings are examples only. Because of component tolerances, the optimum setting for each transceiver will probably be different.
Test Channel 7 [1] 8 [1] [1] If the transceiver operates on only narrow or wide band channels, program only chan- nels 1-6, and program them for the type of channels used (narrow or wide band). If the transceiver operates on both wide and narrow band channels, program additional channels 7 and 8 for the other type of operation.
ADJUSTMENT PROCEDURE in the upper part of the screen is for the currently selected channel. 5. To move the cursor between the parameters on the left side of the bar graph, press the To change a parameter, press the backspace, or spacebar keys. Refer to the individual adjustment descriptions for more information on the functions performed using this screen.
4. Press (Enter) again to select the second adjust chan- nel. Key the transmitter and adjust for the displayed frequency. Unkey the transmitter and press (Enter) again to exit this function. 6.4.2 OUTPUT POWER ADJUST 1. Select the high power channel in the middle of the band (Test Ch.
Repeat for the other three filters. a. Connect a SINAD meter with a 4-ohm load to the external speaker jack (see Figure 6-4). b. Select “BPF T1” and press the adjust keys ( / PgUp/PgDn, or spacebar/backspace) to obtain minimum distortion.
3. Connect an RF signal generator to the antenna jack. Set it to the channel frequency with an output mod- ulated with 1 kHz at the following deviation: Wideband (30 kHz) Models - 3.5 kHz Narrowband (12.5 kHz) Models - 1.75 kHz 4.
ADJUSTMENT PROCEDURE NOTE: Perform the preliminary setup described in Section 6.2 before proceeding with these adjustments. 6.6 PLL ADJUSTMENT (UHF MODELS) 1. Remove the bottom cover by removing four screws. Connect a DC voltmeter to check point CP1 shown in Figure 6-6. 2.
6.7.4 DTCS WAVEFORM ADJUST 1. Select the channel on the low end of the pro- grammed for DTCS code 007N (Test Ch. 5). 2. On the computer screen, scroll to “DTCS N” if set- ting a narrow band channel or “DTCS W” if setting a wideband channel.
Repeat for the other three filters. Manual Adjustment a. Connect a SINAD meter with a 4-ohm load to the external speaker jack (see Figure 6-6). b. Select “BPF T1” and press the adjust keys ( / PgUp/PgDn, or spacebar/backspace) to obtain minimum distortion.
UHF (7640) EXPLODED VIEW November 1998 FOLDOUT 7-22 (VHF Exploded View) Part No. 001-7600-001...
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SECTION 8 - SCHEMATIC DIAGRAMS AND COMPONENT LAYOUTS DTCS IC7a IC7d CPU5 RESET CPU5 IC2.Q1 COM1-COM3 SEG1-SEG32 BACK LIGHT CTRL DS2-DS11 Q3.D6 AF CH U/D.Etc KEY X8 KR0-KR3 SW2-SW9 KS0.KS1 POSW POSW CLONE CLONE HANGER COMMON LINE LINE RX LINE TX LINE DATA BUS LINE RIPPLE...
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VHF (7610) Transistor Basing Diagrams VHF (7610) Diode Basing Diagrams November 1998 Part No. 001-7600-001...
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November 1998 VHF (7610) MAIN BOARD BOTTOM VIEW FOLDOUT Part No. 001-7600-001...
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November 1998 VHF (7610) MAIN BOARD TOP VIEW Part No. 001-7600-001...
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V-UP DS10 V-DN J1 (To Microphone) J2 (To Main Unit) November 1998 Part No. 001-7600-001 VHF/UHF FRONT UNIT BOARD TOP VIEW VHF/UHF FRONT UNIT BOARD BOTTOM VIEW 8-10...
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