Uniden 2020 User manual

UNIDEN 2020
Sid 1(26)
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) FrequencyCounter.
2-2. Adjustment Procedures
(1) Connect FrequencyCounter 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..
2-3Adjustment 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 2(26)
3.R.I.T CIRCUIT ALIGNMENT
3-1Test Equipment Required
(1) None
3-2Adjustment 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.
(3) Set R.I.T knob to 0 at the WIDE (normal) position.
(4) Adjust potentiometer R665 in AVR unit to obtain the same beat at ON or
OFF of the R.I.T SWITCH.
(5) Again try the same adjustment on R664 in AVR at the NARROW (pull)
position of R.I.T.
4. S-METER ADJUSTMENT
4-1Test Equipment Required
(1) Standard Signal Generator (SSG)
4-2Adjustment Procedures
(1) Connect SSG output to antenna jack.
(2) Set MODE SWITCH to USB.
(3) Set BAND SWITCH to 14.0, SEGMENT SWITCH at 200/300, and tune the
main dial to recive 14.200 MHz signal.
(4) TurnRF GAIN CONTROL fully clockwise.
(5) Turn RF ATT CONTROLL fully clockwise.
(6) Tune PRESELECT knob to obtain maximum nois output.
(7) Set SSG frequency at other than 14.200 MHz and keep minimum output
level.
(8) Turn potentiometer R387 in the IF unit fully counterclockwise. Then, return
it slowly clockwise and stop just befor S-Meter start moving.
(9) Feed 40 dB of 14.200 MHz unmodulated output to tranciver, and turn the
dial to obtain maximum S-Meter readings.
(10) Adjust potentiometer R389 on the IF unit, so that the S-Meter indicator S-9
readings.
(11) Set SSG Output at 80 dB.
(12) Adjust potentiometer R392 on the IF unit, so that the indicator shows full-
scale readings.
(13) Repeat (9) –(12) adjustment until both prospected readings ar available.

UNIDEN 2020
Sid 3(26)
5. 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.
(2) Set two AGs and ATT as described in Fig. 5-2-1, to provide two-tone signals
to the microphone jack.
(3) Tune and load transmitter at 14.2 MHz to obtain maximum outout.
(4) Set MODE SWITCH to USB.
(5) Turn MIC GAIN CONTROL fully clockwise.
(6) Set Meter Switch to ALC position.
(7) Set AG 1 frequency to 1,900 Hz and AG 2´s to 2300 Hz.
(8) Measure each output voltage at the mV and set them to 10 mV.
(9) Adjust and set the attenuator just before ALC Meter starts moving.
(10) Reduce attenuation for 10 dB and increase microphone input.
(11) Adjust potentiometer R388 on the IF unit so that the indicator points the
right end of the green ALC scale on the meter.
1
2
4
3
R = 200 ohm
R
R
R
AG 1
AG 2
ATT
Fig 5-2-1

UNIDEN 2020
Sid 4(26)
RECEIVER ALIGNMENT
1. ALIGNMENT PREPARATIONS
1-1. Set controls and switches on the front panel as indicated
below:
(1) FUNCTION SWITCH INT.
(2) HTR SWITCH OFF
(3) STANDBY SWITCH PTT
(4) R.I.T SWITCH OFF
(5) N.B. SWITCH OFF
(6) AGC SWITCH FAST
(7) MODE SWITCH USB
(8) RF GAIN SWITCH Fully Clockwise
(9) AG GAIN CONTROLL Center position.
(10) SEGMENT SWITCH 0/500 KHz
(11) RF. ATT. CONTROL Fully Clockwise
(12) OTHER CONTROLS & SWITCHES Option
1-2. Set rera panel switch and jack as indicated below:
(1) RF POWER AMP SWITCH Off
(2) Connect external speaker (4 ohms), or 4 ohm dummy load to the EXT. SP
jack.
1-3. Set PWR SWITCH to ON after completion of all preparations as mentioned
above.
2. RX RF UNIT ALIGNMENT
2-1. Test Equipment Required
(1) Standard Signal Generator (SSG)
(2) AF milli-volt Meter (mV)
2-2. IF Trap Coil Alignment
(1) Connect SSG output to antenna jack.
(2) Connect mV to speaker or dummy load in parallel.
(3) Set BAND Switch to 7.0, and SEGMENT SWITCH to 0/500.
(4) Turn PRESELECT CONTROL fully counter-clockwise.
(5) Provide 80 dB of 6.187 MHz unmodulated signal from SSG.
(6) Adjust L01 and L207, so as indicate minimum readings on S-Meter or mV.

UNIDEN 2020
Sid 5(26)
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.
(4) Get maximum S-Meter or mV readings by adjusting tuning coils as indicated
(L201 –L213) on each band.
(5) Control SSG output during this process to make adjustment easier.
Chart 2-2-1
ABC
BAND SEGMENT FREQ. (MHz) COIL No.
15.0 0/500 15.000 L201, L208
3.5 100/600 3.600 L202, L209
7.0 100/600 7.100 L203, L210
14.0 200/700 14.200 L204, L211
21.0 200/700 21.200 L205, L212
28.5 0/500 28.500 L206, L213
2-4. IF Tuning Coil Alignment.
(1) Connect SSG and mV as 2-2 (1), (2)
(2) Set BAND SWITCH to 14.0, and SEGMENT SWITCH to 200/700.
(3) Provide 40 dB of 14.200 MHz unmodulated signal from SSG.
(4) Tune the main dial and receive the input signal, then control PRESELECT
knob to get maximum output readings.
(5) Adjust L214 –L218 so as to get the maximum readings on S-Meter or mV.

UNIDEN 2020
Sid 6(26)
3. 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.
(1) Process the same as 2-4, (1) –(4).
(2) Adjust L351 –L354 to get the maximum readings or S-Meter or mV.
3-4. Carrier Balance Adjustment.
(1) Process the same as 2-4, (1) –(4), but note that SSG output should be 20 dB.
(2) Adjust CARRIER BALANCE potentiometer R374 and trimmer capacitor
C370 to get the maximum readings on mV.

UNIDEN 2020
Sid 7(26)
TRANSMITTER ALIGNMENT
1. ALIGNMENT PREPARATION
1-1. Set controll and swiches on the front panel as folows.
(1) FUNCTION SWITCH INT.
(2STANDBY SWITCH PTT
(3) METER SWITCH IK
(4) MIC GAIN CONTROL Fully counterclockwise
(5) CARRIER CONTROL Fully counterclockwise
(6) OTHER CONTROLS & SWITCHES Option
1-2. Set rear panel switch and jack as indicated below:
(1) RF POWER SWITCH ON
(2) Connect RF power meter (50 ohms impedance) to antenna jack.
1-3. Set PWR and HTR switch to ON after completion of all prepatarions as
mentioned abov.
1-4. Please note following instructions at the position of the
wordings:
OBTAIN MAXIMUM OUTPUT AT…….MHz, which will be mentioned here
after during tuning procedures and marked *
(1) Make 1-1 …. 1-3 preparations.
(2) Set MODE SWITCH to TUNE.
(3) Select BAND and SEGMENT SWITCHES according to the desired
frequency.
(4) Set METER SWITCH to ALC position.
(5) Set PLATE CONTROL knob around the desired frequency range.
(6) Set LOAD CONTROL knob to center position.
(7) Set CARRIER CONTROL knob to center position.
(8) Set STANDBY SWITCH to MANU.
(9) Tune PRESELECT CONTROL to get maximum meter readings.
(10) Set METER SWITCH to PWR.
(11) Adjust PLATE and LOAD controls by turns to get maximum meter
readings.
(12) Reset the STANDBY SWITCH to PPT position.
(13) Turn CARRIER CONTROL knob fully counterclockwise.

UNIDEN 2020
Sid 8(26)
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. Don’t touch part of them.
2. PA IDLING CURRENT ADJUSTMENT
2-1. Test Equipment Required
(1) None
2-2. Adjustment Procedure.
(1) Set MODE SWITCH to USB.
(2) Set STANDBY SWITCH to MANU
(3) Adjust the BIAS potentiometer, R16 on the rear panel so as to indicate
GREEN TRIANGLE MARK on the meter.
3. GENERATOR UNIT ALIGNMENT
3-1. Test Equipment Required
(1) RF voltage Meter
(2) AF milli-volt Meter (mV)
(3) Audio Generator (AG)
(4) Frequency Counter.
(5) Oscilloscope
3-2. Preparations
Take out Generator Unit (PC-080) and put a SERVICE EXTENSION BOARD
in its place, then connect the GENERATOR UNIT to the EXTENSION
BOARD.
3-3. (1) Connect RF voltage meter the (RF VTVM) to Pin 16 of J18.
(2) Adjust L510 to get maximum meter readings.
(3) Remove RF VTVM and connect frequency counter to Pin 16 of J18.
(4) Set MODE SWITCH to USB, and adjust trimmer capacitor C541 so that the
frequency counter indicates 6,187.000 kHz.
(5) Set MODE SWITCH to TUNE, and adjust trimmer capacitor C542 so that
the counter reading indicates 6,187.750 kHz.

UNIDEN 2020
Sid 9(26)
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.
(5) Set STANDBY SWITCH to MANU.
(6) Adjust L501 for maximum VFVM indication. It will indicate around
0.2V r.m.s.
(7) Reset CARRIER CONTROL fully counter-clockwise and STANDBY
SWITCH to PTT.
(8) Connect AG output to the microphone jack and provide 1,500 Hz, 10 mV
output.
(9) Set MODE SWITCH to USB.
(10) Turn MIC GAIN CONTROL fully clockwise.
(11) Set STANDBY SWITCH to MANU.
(12) Adjust L504 for maximum meter indication. It will indicate around
0,3V r.m.s.
3-5. Balanced Modulator Alignment.
(1) This alignment should be taken place after completion of OUTPUT METER
adjustment (5-1, 5-2).
*(2) Obtain maximum output at 14.2 MHz.
(3) Set MODE SWITCH to USB.
(4) Connect RF meter to antenna jack.
(5) Make sure that MIC GAIN CONTROL is set fully counter-clockwise.
(6) Set STANBY SWITCH to MANU and adjust R530 for the minimum meter
indication.
(7) Change MODE SWITCH to LSB and USB by yurns, and make presise
tuning by adjusting R530 to get equal meter readings on both modes.
3-6. AM Modulation Adjustment
(1) This alignment also should be made after completion of OUTPUT METER
adjustment (5-1, 5-2).
*(2) Obtain maximum output at 14.2 MHz.
(3) Set MODE SWITCH to AM
(4) Set STANDBY SWITCH to MANU.
(5) Turn CARRIER CONTROL to get 120 mV reading on the meter.
(6) Connect AG output to microphone jack and provide 1,500 Hz, 10 mV
output.
(7) Set MIC GAIN CONTROL to 3 o’clock position.
(8) Use Oscilloscope to observe output envelope.
(9) Adjust R509 to keep about 80% of output modulation level.

UNIDEN 2020
Sid 10 (26)
4. 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.
(3) Turn CARRIER CONTROL knob fully clockwise.
(4) Set STANDBY SWITCH to MANU.
(5) Adjust each coil in chart 4-2-1-B to get the maximum meter reading.
(6) Return CARRIER CONTROL counterclockwise so as to make tuning more
easily upon adjustment.
(7) Repeat (1) to (6) procedures on each band in order as show in the
chart 4-2-1.
Chart 4-2-1
AB
Adjusting Frequency (MHz) Adjusting Coil No.
3.600 L251, L252, L259
7.100 L253, L260
14.200 L254, L261
21.200 L255, L262
28.500 L256, L263