Fidelity CB-3000FM 40 Channel FM Transceiver Base Station Owner’s Manual
- June 9, 2024
- Fidelity
Table of Contents
Fidelity CB-3000FM 40 Channel FM Transceiver Base Station
CONTROL IDENTIFICATION
- Calibrate Button Reflected Button
- 3. Power/Signal Button Channel
- Button P.A. Button Phones Button
- Channel 9 Indicator
- Channel Selector
- Channel Indicator
- Microphone Socket
- Headphone Socket
- Microphone Holder
- R.F. Gain Control
- Calibrate Control
- Tone Control
- . Squelch Control
- Volume, On/Off Control
- S/RF Meter External Speaker Socket 19
- P.A. Speaker Socket
- Tape Recorder Socket
- 10dB ATT. Switch.
- Antenna Socket
- Microphone
- Microphone Transmit Key
SPECIFICATION SEMICONDUCTORS
General
- Channels: 40 digital PLL synthesised
- Frequency range: See last page
- Operating temperature range:-5 degree C to+45 degree
- C Power Source: 220-250 V A.C 50 Hz
- Dimensions: Depth: 185m/m (7-9/32″)
- Height: 89m/m (3%”) Width: 394m/m (15%”)
Receiver.
- Conversion system: Dual conversion superheterodyne
- IF: 10.7 mHz 1st and 455 kHz 2nd
- Channel display: Digital 7 segment LED’s
- Audio output power:1.5W into 8 Ohm
- Sensitivity: <1 microvolt 20 dB NO
- Adjacent channel rejection: 50 dB
- Spurious emission: <20nW
- Squelch sensitivity: 1 to 10 microvolt
Transmitter.
- Modulation: FM RF power output: 4W
- Frequency tolerance: t1.5 kHz RF
- power attenuator: >10 dB
- Frequency rseponse: 500 to 2,500 Hz +4/-12 dB
- Frequency deviation: >t1.5kHz 1,250 Hz audio
- Adjacent channel power:10 microwatt
- Spurious emission: (1) <50nW within the following frequency bands- 80 MHz- 85 MHz 87.5 MHz- 118 MHz 135 MHz- 118 MHz 174 MHz- 230 MHz 470 MHz- 862 MHz (2)0.25 microwatt at any other frequency.
OTHER FACILITIES
- S.W.R. (Standing Wave Radio) measurement capability
- Headphone socket
- Channel
- LED indicator
- External speaker socket
- P.A. speaker socket.
- Tape recorder socket
CHANGES TO SPECIFICATION
The aim of Fidelity Radio is continually to improve their products and
therefore reserve the right to alter specifications.
DISMANTLING PROCEDURE
TOP CABINET
Remove four screws marked ‘A (above diagram) and five screws marked ‘B’. Then
remove control knobs and the channel selector knob. Slide the top towards the
front to unslot from the push button knobs.
NOTE: If the control knobs are tight, then we suggest that a piece of string be hooked from under neath the knobs and pulled so as to remove the knobs.
CHASSISS
To remove chassis from the base, remove eight screws marked ‘D’ on below diagram. Unsolder the link and the capacitor from the aerial socket and the relevant leads from the microphone socket. Then carefully unslot the chassis from the base. Screws ‘E denote mains transformer bracket fixing screws.
A. LOCAL OSCILLATION SECTION (P.LL. SECTION)
- Set the channel selector to channel 20.
- Set CB to receiving condition, then connect an oscilloscope to pin 14 of IC2 to check for high eve, 1.e. logic” T 7-5V).
- Set CB to transmitting condition and adjust TC1 to give +7.5V on pin 14, i.e. high level. Check: Pin 20 upon transmitting should be at low level, i.e. logic ‘0’.
B. TRANSMITTER
- Set channel at CH -20, connect a frequency counter and RF VTVM to C110 and adjust L6, L8. L9, and L10 to give maximum reading of RF VTVM and frequency of 27-791XX. Then adjust TC2 to correct the frequency to 27-79125.
- Connect an RF wattmeter and a 50 ohm dummy load across the antenna connector and adjust 6, L8, L9, L10, LT1 and Li3 to maximum output. Then adjust L15 so as to give an output power oT
- SVR3 so that the needle of S/RF meter is at the position of 3-5 of RF power indication.
- Modulation level adiustment: Feed a 1KHz audio signal at 5mV to the Mic. input and adjust SVR2 so that the deviation is 1-5 KHz.
C. RECEIVER
- F Section al Connect a sweep signal generator to base of Q3. DConnect an oscioscope to NZs. CSet sweep generator to 455 KHz and adjust 3 and 14 tor maximum output. d) Adjust T5 and T6 for maximum output and an ‘S’ curve.
- Mixer Section
- Connect the SSG to the antenna connector. Set SsG to 27-79125 MHz (CHZ20) and adjust the output so that the modulation signal is at 1 KHz and Dev. 1-5KHZ.
- Connect an oscilloscope and VTVM to the speaker.
- Set the tested unit to CH-20 and adjust L1, 12, L3 and T2 so that the reading on VTVM is at maximum position. when making this alignment the output or the S>o should be adustea nat the ahove for CH-1 and CH-40.
The output level of SSG at CH1 to CH-40 should be within +3db as compared to that at CH-20. Repeat the above process to check the sensitivity of all other channels.