Forward Manual Scope This manual is intended for use by experienced technicians familiar with similar types of communication equipment. It contains all service information required for the equipment and is current as of the publication date.
Product Safety and RF Exposure for Portable Two-Way Radios Compliance with RF Energy Exposure Standards NOTICE: This radio is intended for use in occupational/controlled applications where users have been made aware of the potential for exposure and can exercise control over their exposure. This radio device is NOT authorized for general population, consumer or similar use.
important since the radio generates measurable RF energy exposure only when transmitting (in terms of measuring standards compliance). * Hold the radio in a vertical position in front of the face with the microphone positioned at least one inch (2.5 cm) away from the lips. Keeping the radio at the proper distance is important since RF exposure decreases with increasing distance from the antenna. * For body-worn operation, always use the radio with the HYT Belt-Clip.
Notices to The User This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. One or more of the following statements may be applicable: FCC WARNING This equipment generates or uses radio frequency energy.
INFORMATION TO THE DIGITAL DEVICE USER REQUIRED BY THE FCC This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can generate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.
Contents Brief Introduction LCD Display Software Description Circuit Description CPU Pins Adjustment Description Part List 1 Assembly and Disassembly for Repair Exploded View Part List 2 Packing TC1688P PC Board View TC1688P Block Diagram TC1688P Schematic Diagram Specifications 6
Brief Introduction 1. Antenna 2. Programming Jack 3. Speaker/Mic Jack 4. Power/Volume Knob Rotate the Power/Volume Knob clockwise until a “click” is heard to turn the radio on, fully counter clockwise to turn the radio off. When the radio is on, turn the knob to adjust volume. 5. LCD Display Indicate operation status of the radio. (Refer to “LCD Display” for details) 6. MENU key In standby mode, briefly press MENU key to display current channel information and hold down this key to enter menu mode.
Used to select the channel/interference eliminator code upwards or change menu settings. 13. PTT button Press and hold PTT, radio operates in transmit mode. Release PTT, radio returns to receive mode. 14. Belt Clip Used to clip radio on your belt. 15. Charging Connectors Connect the charging connectors with that on the charger to begin charging.
LCD Display 1. Battery Meter, used to indicate the battery power. 2. Appears when setting the Alarm Clock or the Alarm Clock is on; Flashes when the Alarm Clock rings. 3. Appears when keypad lock is on. 4. Appears when setting the call tone. 5. Appears when receiving signals from the selected channel. 6. Appears when transmitting. 7. Appears when transmitting/receiving is enabled. 8. Indicate that the number on the LCD displays interference eliminator code and channel number.
Software Description Radio Feature Description 4 Feature 56 UHF frequencies available Selectable number of available channels 1-8 Selectable 121 Interference Eliminator Codes LCD Display 5 6 LCD Backlight Keypad Lock 7 VOX Feature 8 Five VOX Sensitivity Levels Available 9 10 Battery Power Indicator Low Battery Alert 11 Channel Scan 12 Battery Save (Sleep Mode) 13 14 Clock Display and Alarm Clock Five CALL TONES available 15 PC Programmable 16 17 Enable/Disable Certain (through PC program
Radio Modes User Mode Conventional Mode Clock and Alarm Clock Setting Mode MENU Mode Channel Setting Mode Dealer Mode PC Programming Mode Wired Clone Mode Default Setting Mode Functions and Operations 1. Conventional Mode Turn the power on. If no key is pressed, the radio will enter conventional mode.
2. Clock and Alarm Clock Setting Mode Turn the power on while holding down CALL key and PTT key simultaneously. After 2 seconds, the radio enters clock and alarm clock setting mode. Press UP/DOWN to select upwards/downwards. Press MENU key to save and go to next setting item. Press CALL key to save and go to the first setting item. If the current item is the first setting item, press CALL key to save and exit.
the first setting item, press CALL key to save and exit. In this mode, you can operate as following: z Select channel number from 1 to 8; z Select frequency number from 1 to 56; z Select interference eliminator code from 0 to 121; z Set the number of available channels from 1 to 8; z Scan Add/Delete. 5. PC Programming Mode Insert programming cable into the programming jack and then turn the power on, the radio enters PC programming mode. 6.
Circuit Description 1. Frequency Configuration The receiver utilizes double conversion. The first IF is 21.7 MHz and the second is 450 KHz. The first local oscillator signal is supplied from PLL circuit. PLL circuit in the transmitter generates the necessary frequencies. Figure 1 shows the frequency configuration. Frequency range: TC1688P: 460—470MHz (Please refer to “appendix1: TC1688P frequency chart” for more details.
2) First Mixer The signal from RF amplifier is mixed with the first local oscillator signal from PLL frequency synthesizer in the first mixer Q15 to generate a 21.7 MHz first IF signal. The first IF signal is then fed through the 21.7MHz crystal filter F2 to remove spurious signals from adjacent channel. 3) IF Amplifier The first IF signal is amplified at Q6 and then enter the IF process chip IC3. The signal is mixed with the second local oscillator signal to generate a 450KHz second IF signal.
6) Receiving CTCSS/CDCSS signal 300Hz-and-higher audio frequency of the signal output from IC3 is filtered by low-pass filter IC2-B, C,D. The resulting signal TI enters the microprocessor IC8. IC8 determines whether the CTCSS/CDCSS matches the pre-set value, and controls the RX-MUTE, APA and the speaker output sounds according to the squelch result. 3. PLL Synthesizer PLL circuit generates the first local oscillator signal for reception and the RF signal for transmission.
4. Transmitter 1) Transmitting AF The AF signal from the microphone passes through a pre-emphasis circuit, is amplified and filtered by a low-pass filter at IC6-A, B, Q5 and Q7. The resulting signal enters VCO for direct modulation. (See figure 5) 2) CTCSS/CDCSS Encoder The necessary signal for 38 CTCSS and 83 CDCSS encoder is generated by TO pin of IC8 and FM-modulated to the PLL reference signal.
5. Power Supply IC4 supply stabilized power for the control circuit. In transmit mode, IC9 is turned on and supply voltage for the transmit VCO; Q2 is turned on and supply operation voltage for the transmitting front-end amplifier. In receiving mode, IC9 is turned on and supply voltage for the receive VCO high-frequency amplified circuit; Q1 is turned on and supply operation voltage for the receiving circuit. 6. Control System The IC8 CPU operates at 4.
Appendix 1: Frequency Chart (Initialization) Frequency No. Frequency (MHz) Frequency No. Frequency (MHz) 1 464.5000 29 462.9125 2 464.5500 30 464.4875 3 467.7625 31 464.5125 4 467.8125 32 464.5375 5 467.8500 33 464.5625 6 467.8750 34 466.0375 7 467.9000 35 466.0625 8 467.9250 36 466.0875 9 461.0375 37 466.1125 10 461.0625 38 466.1375 11 461.0875 39 466.1625 12 461.1125 40 466.1875 13 461.1375 41 466.2125 14 461.1625 42 466.2375 15 461.
Appendix 2: CTCSS Table Display Number 1 Frequency(Hz) Display Number Frequency(Hz) 67.0 20 131.8 2 71.9 21 136.5 3 74.4 22 141.3 4 77.0 23 146.2 5 79.7 24 151.4 6 82.5 25 156.7 7 85.4 26 162.2 8 88.5 27 167.9 9 91.5 28 173.8 10 94.8 29 179.9 11 97.4 30 186.2 12 100.0 31 192.8 13 103.5 32 203.5 14 107.2 33 210.7 15 110.9 34 218.1 16 114.8 35 225.7 17 118.8 36 233.6 18 123.0 37 241.8 19 127.3 38 250.
Appendix 3: CDCSS Table Display Number CDCSS Display Number CDCSS 39 023 82 331 40 025 83 343 41 026 84 346 42 031 85 351 43 032 86 364 44 043 87 365 45 047 88 371 46 051 89 411 47 054 90 412 48 065 91 413 49 071 92 423 50 072 93 431 51 073 94 432 52 074 95 445 53 114 96 464 54 115 97 465 55 116 98 466 56 125 99 503 57 131 100 506 58 132 101 516 59 134 102 532 60 143 103 546 61 152 104 565 62 155 105 606 63
70 226 113 664 71 243 114 703 72 244 115 712 73 245 116 723 74 251 117 731 75 261 118 732 76 263 119 734 77 265 120 743 78 271 121 754 79 306 80 311 81 315 22
CPU Pins Pin No. Pin Name I/O Description 1 SQ I Squelch detect input 2 EXT-PTT I External Mic PTT detect pin 3 TIBI I 4 TI I 5 NC - 6 NC - 7 CNVSS 8 RESET I Reset detect pin 9 XOUT2 O Auxiliary 10 XIN2 I 32.768KHz crystal 11 VSS 12 XIN1 I Master 13 XOUT1 O 4.
28 VL3 29 VL2 30 VL1 31 SEG12 O 32 SEG11 O 33 SEG10 O 34 SEG9 O 35 SEG8 O 36 SEG7 O 37 SEG6 O 38 SEG5 O 39 SEG4 O 40 SEG3 O 41 SEG2 O 42 SEG1 O 43 FILT-CTL O CTCSS/CDCSS LPF control 44 PLL-EN O PLL enable 45 PLL-CLK O PLL serial clock 46 PLL-DATA O PLL serial data 47 ST-CTL O VOX side-tone control 48 KEY-OUT2 O 49 KEY-OUT1 O 50 KEY-IN3 I 51 KEY-IN2 I 52 KEY-IN1 I 53 EEP-DATA I/O EEPROM serial data 54 EEP-CLK O EEPROM serial
57 NC - 58 TO O CTCSS/CDCSS signal output 59 POW-DET I Power switch detect input 60 EXT-MIC I External Mic detect pin 61 AVSS 62 VREF I Reference power supply input 63 BAT-DET I Battery voltage detect input 64 VOX-DET I VOX signal input GND input pin for A-D converter. Connect to VSS.
Adjustment Description Before the adjustment, please beforehand save the user’s setting. Required Test Instrument 1. Stabilized power supply 1set 1) The supply voltage can be changed between 2V and 6V DC, and the output current is 2A or more; 2) The standard output voltage is 3.6V DC; 3) The power supply output voltage stabilizes. 2. Ammeter 1 set 3. Digital Voltmeter 1 set 4. Radio Communication Test Set 1 set Test and Adjustment 1.
Measurement Item Condition Test Instrument Terminal Adjustment Parts Method Specification/Remarks Radio Communication Adjust Receiving Sensitivity to CH1. MON Press for second 1 to receive. Adjust to CH1 and set SQ as level 1 Squelch Test Set SSG: -119dBm, MOD:1KHz DEV: 1.5KHz FILTER: 0.
Test Set BPF:0.3~3KHz AF OUT: 1KHz/12mV transmit. Adjust to CH2 and CTCSS code automatically turns to “1”. Press PTT to Use screwdriver Radio Communication Test Set LPF:0.3KHz to adjust R153 and R152 so that Antenna CTC frequency Frequency deviation: 0.45±0.05KHz deviation is in the regulated range. transmit. Adjust to CH3 CTCSS /CDCSS Frequency Deviation and CTCSS code automatically turns to “38”. Press PTT to Radio Communication Test Set LPF:0.
Assembly and Disassembly for Repair Fig. 1 Remove the power knob. See figure1. Fig. 2 Remove the four screws on the chassis. See figure 2. Fig. 3 The disassembled unit is shown as figure 3.
Fig. 4 Take out the antenna spring, antenna cover and PCB. See figure 4.
Exploded View 37 36 35 34 33 32 9 8 8 9 10 6 31
Packing 32
Specifications Frequency Range 460MHz-470MHz Number of Channels 56 (Max.) Number of CTCSS 38 Number of CDCSS 83 Frequency Error ≤±2.5PPM Transmitting Power 1.0W Radiated Power 0.2W Transmitter Spurious Emission ≤20uW Modulation Limitation ±2.5KHz Bandwidth ≤8.5KHz Adjacent Channel Power Rejection ≥60dB Modulation AF Distortion ≤10% Receiving Sensitivity ≤0.