Uniden 2020 Manual
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Uniden 2020 Manual

Accessory circuits alignment
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ACCESSORY CIRCUITS ALIGNMENT
1.
NOISE BLANKER Adjustment
1-1.
Test Equipment Required
(1) DC Voltage Meter
1-2.
Adjustment Procedures.
(1) Set MODE SWITCH to USB, and recive 14.200 Mhz.
(2) Activate MARKER OSCILLATOR by pulling out RF ATT knob.
(3) Set NOISE BLANKER SWITCH to OFF.
(4) Tune the main dial to generate about 1,000 Hz beat from a speaker.
(5) Put the meter to the COLLECTOR of Q119.
(6) Adjust L139 and L140 to obtain minimum meter readings.
2.
MARKER OSCILLATOR ADJUSTMENT
2-1.
Test Equipment Required
(1) Frequency Counter.
2-2.
Adjustment Procedures
(1) Connect Frequency Counter to the Pin 1 (Marker output) of J751 on the
operation unit.
(2) Activate MARKER OSCILLATOR by pulling out RF ATT knob.
(3) Tune trimmer capacitor C753, so that the counter indicates 25.000 KHz
± 2 Hz..
2-3
Adjustment by Standard Radio Signals
(1) Connect antenna-to-antenna jack.
(2) Set BAND SWITCH to 15.0 SEGMENT SWITCH at 0/500, and recive 15
MHz Standard Signal (JJY, WWV, etc.)
(3) Pull out RF ATT knob to activate MARKER OSCILLATOR.
(4) Set MODE SWITCH to AM.
(5) Adjust trimmer C753 to make zero beat of calibration signal. It is easlily
adjustable Standard Radio Signal (A2), because double beat is generated.
(6) Adjust attenuator control to make the calibration easy against excessive
incoming signal.
UNIDEN 2020
Sid 1 (26)

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  • Page 1 UNIDEN 2020 ACCESSORY CIRCUITS ALIGNMENT NOISE BLANKER Adjustment 1-1. Test Equipment Required (1) DC Voltage Meter 1-2. Adjustment Procedures. (1) Set MODE SWITCH to USB, and recive 14.200 Mhz. (2) Activate MARKER OSCILLATOR by pulling out RF ATT knob. (3) Set NOISE BLANKER SWITCH to OFF.

  • Page 2: S-Meter Adjustment

    UNIDEN 2020 R.I.T CIRCUIT ALIGNMENT Test Equipment Required (1) None Adjustment Procedures (1) Set the main dial at 50, on any BAND or SEGMENT selection. (2) Pull out RF ATT knob and make the marker oscillator work to obtain about 1,000 Hz beat.
  • Page 3 UNIDEN 2020 ALC METER ADJUSTMENT 5-1. Test Equipment Required (1) RF Power Meter. (2) Audio Generator (AG) x 2. (3) Audio Attenuator (ATT) (4) AF Milli- volt Meter (mV) 5-2. Adjustment Procedures (1) Connect RF power meter to antenna jack.

  • Page 4: Receiver Alignment

    UNIDEN 2020 RECEIVER ALIGNMENT ALIGNMENT PREPARATIONS 1-1. Set controls and switches on the front panel as indicated below: (1) FUNCTION SWITCH INT. (2) HTR SWITCH (3) STANDBY SWITCH (4) R.I.T SWITCH (5) N.B. SWITCH (6) AGC SWITCH FAST (7) MODE SWITCH...
  • Page 5 UNIDEN 2020 2-3. Tuning Coil Alignment (1) Connect SSG output and mV as 2-2 (1), (2). (2) Set PRESELECT CONTROL to center position. (3) Select BAND SWITCH and SEGMENT SWITCH in order, starting from 15.0 MHz according to the chart 2-2-1-A, and also provide listed frequency signals (unmodulated 40 dB) from SSG as show in the chart 2-2-1-B and recive them by tuning the main dial.
  • Page 6 UNIDEN 2020 IF UNIT ALIGNMENT 3-1. Test Equipment Required (1) Same as 2-1 3-2. Preparations Take out IF UNIT (PC-078) and put SERVICE EXTENSION BOARD in its place, then CONNECT the IF UNIT to the EXTENSION BOARD. 3-3. Coil Adjustment.

  • Page 7: Transmitter Alignment

    UNIDEN 2020 TRANSMITTER ALIGNMENT ALIGNMENT PREPARATION 1-1. Set controll and swiches on the front panel as folows. (1) FUNCTION SWITCH INT. (2 STANDBY SWITCH (3) METER SWITCH (4) MIC GAIN CONTROL Fully counterclockwise (5) CARRIER CONTROL Fully counterclockwise (6) OTHER CONTROLS & SWITCHES Option 1-2.
  • Page 8 UNIDEN 2020 CAUTION (1) During transmitter tuning, do not keep the final tube running untuned for a long period of time. Make quick adjustment of PLATE and LOAD controls. (2) High voltage is generated especially inside of the final amplifier and also bottom of the PA compartment.
  • Page 9 UNIDEN 2020 3-4. Modulator Output Coil Adjustment (1) Connect RF VTVM to Pin 6 of J16 (IF UNIT). (2) Set RF AMP SWITCH on the rear panel to OFF. (3) Set MODE SWITCH to TUNE. (4) Turn CARRIER CONTROL knob fully clockwise.
  • Page 10 UNIDEN 2020 TRANSMITTER RF CIRCUITS ALIGNMENT 4-1. Test Equipment Required (1) RF Power Meter. 4-2. Tuning Coil Adjustment *(1) Obtain maximum output at each frequency in chart 4-2-1-A, but note that PRESELECT CONTROL should be center position. (2) Set METER SWITCH to ALC.

  • Page 11: Feedback Neutralizing

    UNIDEN 2020 RF output meter adjustment 5-1. Test Equipment Required (1) RF Power Meter. 5-2. Adjustment Procedure. *(1) Obtain maximum output at 14.2 MHz (2) Set METER SWITCH to PWR. (3) Turn CARRIER CONTROL knob fully clockwise. (4) Adjust the meter adjustment potentiometer R08 on the rear panel, so that the IK reading shows 200 mA.
  • Page 12 UNIDEN 2020 POWER SUPPLY ALIGNMENT AVR UNIT (PC-082) ALIGNMENT. 1-1. Test Equipment Required (1) DC Voltage Meter. 1-2. Voltage Measurement and Adjustment. 8.2V DC Power Source: Connect DC Voltage meter to Pin 3 of J651, and adjust potentiometer R659 to get 8.2V ±0.2V of meter readings.
  • Page 13 UNIDEN 2020 LOCAL OSCILLATOR CIRCUITS ALIGNMENT VFO UNIT (PC-083, PC-084) ALIGNMENT 1-1. Test Equipment Required (1) Frequency Counter (2) RF voltage Meter (RF VTVM) 1-2. Oscillator Frequency Adjustment. (1) Set FUNCTION SWITCH to INT (2) Set R.I.T SWITCH to OFF (3) Connect Frequency Counter to Pin 5 J701.
  • Page 14 UNIDEN 2020 PLL UNIT (PC-086, PC-087) ALIGNMENT. 2-1. Test Equipment Required (1) Frequency Counter (2) RF voltage Meter (RF VTVM) 2-2. VCO Unlocked-oscillation Frequency Adjustment. (1) Set FUNCTION SWITCH to R. EXT. (2) Connect Frequency Counter to the DRAIN of Q807.
  • Page 15 UNIDEN 2020 LOCAL OSCILLATOR UNIT (PC-092) ALIGNMENT. 3-1. Test Equipment Required (1) RF Voltage Meter. (2) Frequency Counter. (3) Sweep Generator. (4) Oscilloscope. 3-2. Xtal Oscillator Output Adjustment. (1) Connect RF voltage meter to TP102. (2) Select BAND SWITCH in order, starting from 15.0 MHz, according to chart 3-2-1-A and adjust each coils in 3-2-1-B so as to get 1.5V r.m.s.
  • Page 16 UNIDEN 2020 3-5. Bandpass Filter Adjustment. (1) Connect test equipments as show in Fig 3-5-1 Fig 3-5-1 Oscilloscope Sweep Generator TP101 J104 (1) (2) Select BAND SWITCH in order, starting from 15.0 MHZ according to the chart 3-5-1 and adjust each coil (3-5-1-C) so as to get the assigned wave from on oscilloscope (3-5-1-B) respectively.

  • Page 17: Voltage Measurements

    UNIDEN 2020 VOLTAGE MEASUREMENTS 1. TUBE Pin No Section Tube V251 -3.2 (12.6) (6.3) TX RF 12BY7A -16.5 (12.6) (6.3) V1001 0.29 (12.6) 0.29 0.29 (6.3) 6146B (12.6) (6.3) Final V1002 0.29 (6.3) 0.29 0.29 6146B (6.3) V1001 0.23 (12.6) 0.23...
  • Page 18 UNIDEN 2020 Section Q Nr. TYPE T or R E or S C or D B or G1 Q 401 2SK30AY 2SC372Y 2SC372Y 2SC372Y 2SA495Y 10.2 2SC372Y 2SC735Y 12.0 2SC372Y CW R 2SC372Y Q 502 2SC380Y 2SC372Y 2SC372Y SSB T 2SC380Y T &...

  • Page 19: Voltage Measurement

    UNIDEN 2020 VOLTAGE MEASUREMENT PLL UNIT Set SEGMENT SWITCH 0 position Set BAND 14.0 MHz Set VFO DIAL E or S B or G1 C or D Q 803 2SC1682 1.2 V 1.7 V 5.0 V 2SC373 2SC373 2SK19 2SK19...
  • Page 20 UNIDEN 2020 (0.1 uS/DIV) (0.1 uS/DIV) (5 uS/DIV) (5 uS/DIV) (0.5 uS/DIV) (0.5 uS/DIV) Sid 20 (26)
  • Page 21 UNIDEN 2020 PLL Unit (PC-086) Operation Unit (PC-085) Sid 24 (26)
  • Page 22 UNIDEN 2020 Sid 21 (26)
  • Page 23 UNIDEN 2020 (5 uS/DIV) (0.1 uS/DIV) (0.1 mS/DIV) (5 uS/DIV) (0.1 mS/DIV) Sid 22 (26)
  • Page 24 UNIDEN 2020 (0,1 Us /DIV) (20 Us /DIV) (20 Us /DIV) (1 Us /DIV) (0,1 Us /DIV) (20 Us /DIV) Sid 23 (26)
  • Page 25 UNIDEN 2020 Sid 25 (26)
  • Page 26 UNIDEN 2020 Sid 26 (26)

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