FRS 3000-PK SERVICE MANUAL 2-WAY PORTABLE HANDHELD RADIO OCTOBER 19, 2001 1/21
CONTENT 1. GENERAL 1.1 General 1.2 Characteristic 1.3 Composition 2. SPECIFICATION 2.1 General Specification 2.2 Electrical Specification 3. OPERATION 3.1 ICON on LCD 3.2 Key Functions 3.3 Setting and Operation 4. ADJUSTMENT 4.1 4.2 4.3 4.4 4.5 4.6 Frequency synthesizer Transmitter Transmitter Test Receiver Receiver Test Symptoms, check point & Correction 5. DESCRIPTION OF RADIO CIRCUIT 5.1 Frequency Synthesizer 5.2 Receiver 5.3 Transmitter 6. BLOCK DIAGRAM 7. SCHEMATIC 8. COMPONENT PARTLIST 9.
1. GENERAL 1.1 GENERAL This equipment, FRS 3000-PK is called 2 way portable handheld radios. The frequency range is 462 ~ 467MHz, UHF operating Channels for international 2 way radio. Also it has a 38 CTCSS feature to get the clear communication without interference. 1.2 CHARACTERISTIC a) All active device in this radio is composed of semiconductor and high density IC. b) To design this radio in compact and weight approximately 140g with out battery.
2. SPECIFICATION 2.1 GENERAL SPECIFICATIONS a) Frequency range : 462.5625 ~ 467.7125 MHz b) Output Impedance : 50Ω Unbalanced c) Modulation Type : 8K0F3E d) Communication Mode : Half duplex e) Channel Capacity : 14 channel f) Channel Spacing : 12.5 kHz g) Power : 6.0V(alkaline) h) Battery Life : Alkaline.1000mAh >14.5hours (Tx5%, Rx5%, Stand-by90%) i) Operating Temperature : -20°C ~ +60°C j) Dimension : 107(H) x 58(W) x 28(D) k) Weight : 140g (without battery) 2.
3. OPERATION 3.1 ICONS on LCD 1) Monitor indicator : Appears when the CTCSS isn’t in use and squelch is open. 2) Key lock indicator : Indicates that the key lock function is in use. 3) Beep ON/OFF indicator : Appears while key tone is in use. 4) Roger On/Off indicator : Appears while Roger tone is in use. 5) Battery indicator : Indicates the battery status 6) Receive signal indicator : Appears when receiving signal or squelch noise is existing. 7) ID indicator : Appears when the ID function is in use.
1) PTT switch : Push and hold to transmit ; release to receive. 2) Monitor : Press and hold this key for over 2 seconds to enable the receive CTCSS feature. 3) Up/Down key : In the stand-by mode, Pressing this button will increment or decrement the listening volume. When in function edit mode, this button will be used to adjust the unit settings.. 4) Scan / Lock key : Push this key to momentarily to enable or disable the scan. Press and hold this key for over 2seconds to lock or unlock keypad.
button is pressed, the LED will light red. These LED’s are used for backlighting as well. 9)External speaker/mic jacks : Connect an optional speaker/mic or headset, if desired. The internal mic and speaker will not function when either is connected. 2) Function display Monitor Indicator: Icon appears when the monitor button is pressed and the channel monitor function is activated. Key Lock Indicator: Icon appears when the keypad is locked. This function disables keys such as channel up/down and mode.
Scan Indicator: This function allows users to scan a channel to search for a valid signal. Dual Watch mode Indicator: Icon appears when dual watch mode is active. Voice Activated Transmission (VOX) Indicator: This function allows handsfree conversation. The Icon appears when the VOX mode is activated. Out of Range Alarm Indicator: When this function is active, Icon blinks the receiving signal is getting weaker. The Icon stops blinking when the receiving signal comes back to the normal strength.
To select the channel * Turn the radio on. * Press MODE button once, [XX] digit will blink on the LCD. XX is a channel. * Press up[ù]or down[ü] button to choose the channel. * Press the PTT button or MODE button to confirm. To set the tone codes(CTCSS) * Press MODE button once more, [XX 00 up to 38] will appear and CTC icon and tone code digit will blink on the LCD. “00” means no CTCSS code. * Press up[ù]or down[ü] button to choose the desired sub-channel to use.
“01 up to 15” means the channel that is dual-watched. * Press the PTT button or MODE button to confirm. 5) Roger tone This feature will give the tone signal to other parties when transmitting finished (when PTT button is released.) To activate or disable the Roger tone * Press the Mode button until [rb on or oF] and the roger icon blink on the LCD. * Press the up[ù]or down[ü] button. * Press the PTT button or MODE button to confirm.
9) Call Ringer Selection Mode This feature Provides 3 user selectable call ringer signal. To set your favorite call ringer signal. * Press the MODE button until the [C 01 or up to 03] appears on the LCD. * Press the up[ù]or down[ü] button to select the call melody type. * Press the PTT button to confirm. * To activate the call, click the “PTT” button twice quickly. 10) Transmitting * Press and hold the PTT button (The LED light red during transmission.
14) Monitoring the Channel It is used for listening the week signal or to here all activities on the channel by Manually overriding channel sub tone code setting. To activate the monitor feature * Press and hold the “MON”(monitor) button for over two seconds. * When you hear the sound, release the “MON” button. ( The monitor icon will appear on the LCD.) To disable the monitor feature * Press and hold the “MON”(monitor) button for over two seconds. ( The monitor icon will disappear on the LCD.
4. ADJUSTMENT 4-1. Frequency synthesizer a) After connecting the power meter and dummy load(50 ohm), join the antenna connector of FRS 3000-PK with above equipment. b) Check the voltage between RF BOARD BT POINT & GND in digital volt meter c) Then set the low channel of FRS 3000-PK the lowest frequency. d) After pressed PTT key of FRS 3000-PK, check if the lowest frequency of Tx channel to DC 1.5V in the voltage of test point(VT).
b) Connect DC 6.0V voltage preset to EUT. c) Connect ‘Power Meter’ and ‘Dummy Load ( 50 ) d) Adjust Tx frequency according to trimming trimmer VC1. e) Connect AF Oscillator to mic terminal for conform modulation degree. f) Adjust the frequency of AF Oscillator to 1 kHz and adjust AF level Should be 100mV. g) Checking Oscilloscope and Modulation Meter. Max deviation should be in ±5 kHz. 4-3. Transmitter Test a) Output Power Test Power(DC 6.0V) should be Max. 500 mW(ERP) and in –50% range.
b) Connection method SSG EUT Power Supply 4 Load Oscilloscope AV VTVM Distortion Meter SINAD Meter c) The Conform of Rx sensitivity 1) Adjust SSG to channel frequency. 2) Adjust modulation frequency , 1Khz to modulation degree, 3kHz. 3) After adjusting the frequency of SSG to channel frequency, RF level sets to –47dBm. d) The Conform of Squelch sensitivity 1) Set the standard channel. 2) In squelch mode, SQ volume VR2 must be turned counterclockwise.
4-6. Symptoms, Check point & Correction a) Diagnosis method 1) Check each switch to work well. 2) Check voltage of battery. 3) Problem develops from transmitter or receiver? b) Troubleshooting 1) Transmitter -. Power key is on condition but does not work. Battery could completely discharge. Battery cell twist .. Touch problem come between Battery and Radio. -. Fail to transmit. Run out of battery or charge problem. Fault of PTT key. Fault of Q4,Q3,Q2.Q1 -.
IF IC U8 problem. VCO circuit problem. -. Rx sensitivity is weak Antenna mounting problem. Receiver front-end circuit problem. Local oscillation frequency deviation. FL1,FL2 SAW filter fail. VCO circuit problem. -. Squelch does not work IF IC U8 problem. Control logic circuit problem.
5. DESCRIPTION OF RADIO CIRCUIT 5-1. Frequency synthesizer Frequency synthesizerconsists of VCO, loop filter and RFIC. RFIC includes MIX,IF, Compander and PLL. Frequency synthesizer uses the PLL of thte RFIC. a) VCO VCO is composed of ONE VCO Oscillation circuit takes colpitts circuit using variable Diode. The VCO generates FRS frequencies and consists of L17, D5, C65, L19, C69, C70, R45, R44, R46, C71, C72, Q14, R47, C74, R48, Q15, L29, C147, C151.
L21,C87 resonate serially and make impedance matching at receiver bandpass filter.(FL1,FL2) b) Front End Front-end has Q6 to provide a high sensitivity and low noise feature. It employs SAW filter as band pass filter to eliminate image frequency and to produce enough pass band by Q6 input and output. c) 1st Mixer The receiver which has been amplifier in the RF front-end is provided to the base of the 1st mixer Q7.
Max. Frequency modulation deviation is adjusted by U4,VR1 keeps noise and audio from entering to VCO at time of Tx. Audio modulation and Audio Amplification has characteristic of 6 /OCT pre-emphasis by U4. 9.
10. CHANNEL DATA 1) FRS Frequency Chart Channel 1 2 3 4 5 6 7 Frequency (MHz) 462.5625 462.5875 462.6125 462.6375 462.6625 462.6875 462.7125 Channel 8 9 10 11 12 13 14 Frequency (MHz) 467.5625 467.5875 467.6125 467.6375 467.6625 467.6875 467.7125 2) CTCSS Tone Frequency Chart NO FREQ.(Hz) NO FREQ. (Hz) NO FREQ. (Hz) 1 67.0 14 107.2 27 167.9 2 71.9 15 110.9 28 186.2 3 74.4 16 114.8 29 179.9 4 77.0 17 118.8 30 186.2 5 79.7 18 123.0 31 192.8 6 82.5 19 127.3 32 203.
