PRESIDENT JOHNSON II User manual

JOHNSON II
SERVICE MANUAL

- TECNNICAL CHARACTERITICS
1 - GENERAL:
- Multiconfiguration (E, d, EU, EC, U, PL)
-E ⇒40 channels AM/FM 4W (from 26,965Mhz to 27,405Mhz)
-d ⇒80 channels FM 4W (from 26,565Mhz to 27,405Mhz)
40 channels AM 1W (from 26,965Mhz to 27,405Mhz)
-EU ⇒40 channels FM 4W/AM 1W (from 26,965Mhz to 27,405Mhz)
-EC ⇒40 channels FM 4W (from 26,965Mhz to 27,405Mhz)
-U ⇒40 channels FM 4W (from 26,965Mhz to 27,405Mhz)
40 channels FM 4W (from 27,60125Mhz to 27,99125Mhz)
-PL ⇒40 channels AM/FM 4W (from 26,960Mhz to 27,400Mhz)
-Channel step
-10KHz
-Class of emission
-AM(A3E)/FM(F3E)
- Power supply
-13,2V (from10,8V to 15,6V)
- Antenna impedance
- 50Ω
- Dimensions(in mm)
- 170(W)x150(D)x52(H)
- Weight
- 1Kg
2 - TRANSMISSION:
- Frequency allowance
-±300Hz
- Transmission interference
-Inferior to 4nW(-54dBm)
- Audio frequency response
-From 300Hz to 3kHz in AM/FM
- Emitted power in the adjacent channel
-Inferior to 20µW
- Microphone sensitivity
-Inferior to 10mV
-Current drain
-2A(in transmission mode with modulation)
- Modulated signal distortion
-Inferior to 2%

3 - RECEPTION:
-Maximum sensitivity at 20dB sinad
-0,5µV(-113dBm) AM/FM
-Audio frequency response
-From 300Hz to 3kHz in AM/FM
-Adjacent channel selectivity
-Superior to 60dB
-Frequency image rejection
-Superior to 60dB
-Intermodulation response
-Superior to 54dB
-Maximum audio power
-5W
-Squelch sensitivity
-Threshold 0,2µV(-120dBm)/Tight 1mV(-47dBm)
-Current drain
-400mA nominal/1000mA maximum

ALIGNMENT PROCEDURE
(JOHNSON II)
* VCO/PLL PORTION
- Alignment procedure
- Test points
- Frequencies chart
* TRANSMITTER
- Alignment procedure
- Test points
* RECEIVER
- Alignment procedure
- Test points
Test equipement required
Frequency counter 200 Mhz HF Generator
DCVolmeter BFVolmeter
Distortiometer HFVolmeter
Wattmeter - Dummy load Osilloscope
FM linear detector Load 8 Ω
AF generator Sinad meter
Conditions of Measurements on HF Generator
Reception
AM mode: Level - 107 dBm Frequency 1 KHz with 60% of modulation.
FM mode: Level - 107 dBm Frequency 1 KHz with 1,2KHz of deviation.
Transmission
Frequency1 KHz 30mV.

ALIGNMENT VCO/PLL
1 - Alignment procedure(13,2V;configuration”EU,E,d”)
STEP CONDITION ADJUSTMENT REMARKS OF ADJUSTMENT
1 FM(EU,E)
TX mode
Channel 40
L302 Connect a voltmeter to TP 301,
adjust L302 to reach 2V±0,2V.
2 FM(EU,E)
RX mode
Channel 40
L301 Connect a voltmeter to TP 301,
adjust L301 to reach 2,3V±0,2V.
3 FM(EU,E)
TX/RX mode
Channel 1
Connect a voltmeter to TP 301,and check:
Rx Channel 1=2V±0,2V
Tx Channel 1=1,7V±0,2V
4 FM(EU,E)
RX mode
Channel 20
CT301 Connect a frequency counter to TP302,and
adjust CT301 to reach
37,900MHz.
5 FM(EU,E)
TX/RX mode
Channel 1 to 40
or 1 to 80(d)
Connect a frequency counter to TP302,and
check frequencies.

VCO/PLL ALIGNMENT POINTS
TP302

VCO/PLL ALIGNMENT POINTS
L301
L302
TP301

- FREQUENCY LIST (EU,E,EC)
CH Channels
Frequencies
(MHz)
VCO
Frequencies
(MHz)
1 26,965 37,660
2 26,975 37,670
3 26,985 37,680
4 27,005 37,700
5 27,015 37,710
6 27,025 37,720
7 27,035 37,730
8 27,055 37,750
9 27,065 37,760
10 27,075 37,770
11 27,085 37,780
12 27,105 37,800
13 27,115 37,810
14 27,125 37,820
15 27,135 37,830
16 27,155 37,850
17 27,165 37,860
18 27,175 37,870
19 27,185 37,880
20 27,205 37,900
21 27,215 37,910
22 27,225 37,930
23 27,255 37,950
24 27,235 37,930
25 27,245 37,940
26 27,265 37,960
27 27,275 37,970
28 27,285 37,980
29 27,295 37,990
30 27,305 38,000
31 27,315 38,010
32 27,325 38,020
33 27,335 38,030
34 27,345 38,040
35 27,355 38,050
36 27,365 38,060
37 27,375 38,070
38 27,385 38,080
39 27,395 38,090
40 27,405 38,100

- FREQUENCY LIST (PL)
CH Channels
Frequencies
(MHz)
VCO
Frequencies
(MHz)
1 26,960 37,655
2 26,970 37,665
3 26,980 37,675
4 27,000 37,695
5 27,010 37,705
6 27,020 37,715
7 27,030 37,725
8 27,050 37,745
9 27,060 37,755
10 27,070 37,765
11 27,080 37,775
12 27,100 37,795
13 27,110 37,805
14 27,120 37,815
15 27,130 37,825
16 27,150 37,845
17 27,160 37,855
18 27,170 37,865
19 27,180 37,875
20 27,200 37,895
21 27,210 37,905
22 27,220 37,915
23 27,250 37,945
24 27,230 37,925
25 27,240 37,935
26 27,260 37,955
27 27,270 37,965
28 27,280 37,975
29 27,290 37,985
30 27,300 37,995
31 27,310 38,005
32 27,320 38,015
33 27,330 38,025
34 27,340 38,035
35 27,350 38,045
36 27,360 38,055
37 27,370 38,065
38 27,380 38,075
39 27,390 38,085
40 27,400 38,095

- FREQUENCY LIST (U)
CH
CEPT
Channels
Frequencies
(MHz)
VCO
Frequencies
(MHz)
1 26,965 37,660
2 26,975 37,670
3 26,985 37,680
4 27,005 37,700
5 27,015 37,710
6 27,025 37,720
7 27,035 37,730
8 27,055 37,750
9 27,065 37,760
10 27,075 37,770
11 27,085 37,780
12 27,105 37,800
13 27,115 37,810
14 27,125 37,820
15 27,135 37,830
16 27,155 37,850
17 27,165 37,860
18 27,175 37,870
19 27,185 37,880
20 27,205 37,900
21 27,215 37,910
22 27,225 37,930
23 27,255 37,950
24 27,235 37,930
25 27,245 37,940
26 27,265 37,960
27 27,275 37,970
28 27,285 37,980
29 27,295 37,990
30 27,305 38,000
31 27,315 38,010
32 27,325 38,020
33 27,335 38,030
34 27,345 38,040
35 27,355 38,050
36 27,365 38,060
37 27,375 38,070
38 27,385 38,080
39 27,395 38,090
40 27,405 38,100

- FREQUENCY LIST (U)
CH
ENG
Channels
Frequencies
(MHz)
VCO
Frequencies
(MHz)
1 27,60125 38,29625
2 27,61125 38,30625
3 27,62125 38,31625
4 27,63125 38,32625
5 27,64125 38,33625
6 27,65125 38,34625
7 27,66125 38,35625
8 27,67125 38,36625
9 27,68125 38,37625
10 27,69125 38,38625
11 27,70125 38,39625
12 27,71125 38,40625
13 27,72125 38,41625
14 27,73125 38,42625
15 27,74125 38,43625
16 27,75125 38,44625
17 27,76125 38,45625
18 27,77125 38,46625
19 27,78125 38,47625
20 27,79125 38,48625
21 27,80125 38,49625
22 27,81125 38,50625
23 27,82125 38,51625
24 27,83125 38,52625
25 27,84125 38,53625
26 27,85125 38,54625
27 27,86125 38,55625
28 27,87125 38,56625
29 27,88125 38,57625
30 27,89125 38,58625
31 27,90125 38,59625
32 27,91125 38,60625
33 27,92125 38,61625
34 27,93125 38,62625
35 27,94125 38,63625
36 27,95125 38,64625
37 27,96125 38,65625
38 27,97125 38,66625
39 27,98125 38,67625
40 27,99125 38,68625

- FREQUENCY LIST (d)
CH Channels VCO CH Channels VCO
d Frequencies Frequencies D Frequencies Frequencies
(MHz) (MHz) (MHz) (MHz)
1 26,965 37,660 41 26,565 37,260
2 26,975 37,670 42 26,575 37,270
3 26,985 37,680 43 26,585 37,280
4 27,005 37,70 44 26,595 37,290
5 27,015 37,710 45 26,605 37,300
6 27,025 37,720 46 26,615 37,310
7 27,035 37,730 47 26,625 37,320
8 27,055 37,750 48 26,635 37,330
9 27,065 37,760 49 26,645 37,340
10 27,075 37,770 50 26,655 37,350
11 27,085 37,780 51 26,665 37,360
12 27,105 37,800 52 26,675 37,370
13 27,115 37,810 53 26,685 37,380
14 27,125 37,820 54 26,695 37,390
15 27,135 37,830 55 26,705 37,400
16 27,155 37,850 56 26,715 37,410
17 27,165 37,860 57 26,725 37,420
18 27,175 37,870 58 26,735 37,430
19 27,185 37,880 59 26,745 37,440
20 27,205 37,900 60 26,755 37,450
21 27,215 37,910 61 26,765 37,460
22 27,225 37,930 62 26,775 37,470
23 27,255 37,950 63 26,785 37,480
24 27,235 37,930 64 26,795 37,490
25 27,245 37,940 65 26,805 37,500
26 27,265 37,960 66 26,815 37,510
27 27,275 37,970 67 26,825 37,520
28 27,285 37,980 68 26,835 37,530
29 27,295 37,990 69 26,845 37,540
30 27,305 38,000 70 26,855 37,550
31 27,315 38,010 71 26,865 37,560
32 27,325 38,020 72 26,875 37,570
33 27,335 38,030 73 26,885 37,580
34 27,345 38,040 74 26,895 37,590
35 27,355 38,050 75 26,905 37,600
36 27,365 38,060 76 26,915 37,610
37 27,375 38,070 77 26,925 37,620
38 27,385 38,080 78 26,935 37,630
39 27,395 38,090 79 26,945 37,640
40 27,405 38,100 80 26,955 37,650

ALIGNMENT TRANSMITTER
1 - Alignment procedure(13,2V;configuration”EU,E”)
STEP CONDITION ADJUSTMENT REMARKS OF ADJUSTMENT
1 AM(EU)
Channel 20
RT202(LOW) Connect a wattmeter to jack antenna,
adjust RT202 to reach 1W on the
wattmeter.
2 FM(EU)
Channel 20
RT203(HI) Connect a wattmeter to jack antenna,
adjust RT203 to reach 4W on the
wattmeter.
3 FM(EU)
Mod
30 mV 1 KHz
CH 20
RT206(DEV) Adjust RT206 to reach +/- 1,2KHz of
deviation.
4 AM(EU)
Mod
30 mV 1 KHz
CH 20
RT204(AMC) Adjust RT204 to reach +/- 90% of
modulation.
5 AM(E)
Mod
30 mV 1 KHz
CH 20
RT205(ALC) Adjust RT205 to reach +/- 90% of
modulation.

TRANSMITTER ALIGNMENT POINTS
RT206
RT202
RT203
RT205
RT204

ALIGNMENT RECEIVER
1 - Alignment procedure(13,2V;configuration”EU,E,d”)
STEP CONDITION ADJUSTMENT REMARKS OF ADJUSTMENT
1 AM(EU,E)
Channel 20
Middle volume
level.
No squelch active
L1-L3-L6
L7-L8-L9-L10
Connect HF generator to jack antenna
adjusted at ( –107dBm 1KHz 60%),
connect sinad meter to jack EXT speaker
and adjust coils for maximum sensitivity(
≥20dB sinad).
2 FM(EU,E)
Channel 20
Middle volume
level
No squelch active
L 11 Connect HF generator to jack antenna
adjusted at ( –107dBm 1KHz 1,2KHz
Dev),connect sinad meter to jack EXT
speaker and adjust L11 for maximum
sensitivity( ≥20dB sinad).
3 AM(EU,E)
Channel 20
Middle volume
level
No squelch active
RT2(S-METER) Connect HF generator to jack antenna
adjusted at ( –67dBm 1KHz 60%) and
adjust RT2 so that S9 on Smeter.
4 AM(EU,E)
Channel 20
Middle volume
level
Squelch maximum
clockwise
RT1(SQ) Connect HF generator to jack antenna
adjusted at ( –47dBm 1KHz 60%) and
adjust RT1 so that the signal is audible .
5 AM(EU,E)
Channel 20
Middle volume
level
Squelch maximum
counterclockwise
(ASC)
RT401(ASC) Connect HF generator to jack antenna .
Connect sinad meter to jack EXT speaker,
adjust the ouput level of HF generator and
adjust RT401 to reach at the opening ASC
a sinad of 17dB±2dB.

RECEIVER ALIGNMENT POINTS
L1
L3
L6
L11
L7
L8
L9
L10

RECEIVER ALIGNMENT POINTS
RT401
RT2
RT1

JOHNSON II
BLOC DIAGRAM

JOHNSON II
SCHEMATIC DIAGRAM