PRESIDENT uniden BENJAMIN UT-552B User manual

Service Manual
CB TRANSCEIVER
Model BENJAMIN
UT -552B
uniden
CORPORATION

TABLE OF CONTENTS
I. SPECIFICATIONS
A. GENERAL
B. MEASUREMENT CONDITIONS
C. TRANSMITTER
D. RECEIVER
E. GENERAL PERFORMANCE
II. ALIGNMENT PROCEDURES
A. CHECK OF FRONT PCB ASSEMBLY
B. ADJUSTMENT POWER SUPPLY PCB ASSEMBIY
C. PLL SECTION AND CARRIER OSCILLATOR SECTION
ADJUSTMENT_________________________________
D. ALIGNMENT PROCEDURE OF TRANSMITTER
E. ALIGNMENT PROCEDURE OF RECEIVER
F. FRE UENCIES OF LOCAL OSCILLATORS AND IF STAGE
IN RECEIVING STATE ___________________________
G. VOLTAGE CHART : TR & FED
III. MEASUREMENT CONDITIONS
A. SPECIFICATIONS
B. HOWLING TEST STANDARD
C. ALIGNMENT PROCEDURE
IV. BŁOCK DIAGRAM
V. SCHEMATICS/PC BOARDS/WIRING DIAGRAMS
A. EM2- : MAIN PCB (1/2) PARTS LIST ASSEMBLY
TOP VIEW
B. EM2—0123 : MAIN PCB (2/2) PARTS LIST
C. EM2—0125 : FRONT CH SW PCB PARTS ASSEMBLY
BOTTOM VIEW
D. EM3—0126 : PWR SUPPLY PCB PARTS ASSEMBLY
TOP VIEW
E. EM3-0127 : ADDITIONAL PARTS ON BOTTOM
F. EM4—0128 : SR PCB PARTS ASSEMBLY TOP VIEW
G. EM4—0181 : FM PCB PARTS ASSEMBLY

TABLE OF CONTENTS
H. ES2— : SCHEMATIC DIAGRAM (1/3)
I. ES3—0025 : SCHEMATIC DIAGRAM (2/3)
J. ES4—0043 : SCHEMATIC DIAGRAM (3/3)
K. EW2—0022 : WIRING DIAGRAM (1/2)
L. EW3—0032 : WIRING DIAGRAM (2/2)
VI. BILL OF MATERIAL : 17 P.S

I. SPECIFICATIONS
À. GENERAŁ
1. Channels
2. Frequency Range
3- Semiconductors
4. Crystal
5. Microphone
6. Speaker
7. An terma Connector
8. Jacks & Connector
9. Controls
10. Meter
11. Illuminations
12. Size
13. Weight
14. Accessories
B. MEASUREMENT CONDITIONS
1. Power Source
2. An terma Impédance
3. Test Température
4. AM/FM Modulation Frequency
5. SSB Modulation Frequency
Transmit Two Tone
6. Mean Signal Input Level
7. Standard Reference Modulation
AM
8. Standard Reference Modulation
FM
9. Standard Audio Output
10. Audio Frequency, SSB Receive
11. Audio Output Load
26.965 MHz - 27.405 MHz
46 Transistors, 83 diodes, 8 I.C.s
3 LEDS
2
500 û, Dynamic Type
16 û, 7 W Max
M - Type
MIKE-4P METAL, EXT SP-3.5 0.
Channel Selector, Mode Selector
(AM-USB-LSB), FM Mode Selector,
ON/OFF Power Switch & Volume & Squelchj
Mike Gain & RF Gain, Clarifier,
Hi Cut Switch, Noise Blanker-ANL Switch,
Channel 19 Switch
RF Output Power/Signal Strength
Channel Number Indication (LED),
TX Indication, RX Indication (LED)
W : 14 3/8"
H : 3 3/4"
D : 8 7/8"
3 Ibs. 2 oz.
Microphone, Microphone Hanger
220 V (AC)
50 û
25° C
1 kHz
500 Hz, 2.400 Hz
1.000 JJ V
1 kHz, 30%
1 kHz, ± 1.5 kHz Dev.
0.5 W
1 kHz
8 û Résistive
40

12. Measuring Channel : 19
13. Standard Method of Measurement : EIA RS—382 (ISS : 8 — 26— 86)
C. TRANSMITTER
ITEMS MODE UNIT NOMINAL LIMIT
1. Frequency Tolérance at 25°C
(5 minutes after switch on) AM Hz ± 130 ± 800
FM Hz ± 130 ± 800
SSB Hz ± 130 ± 800
2. Carrier Power at No Modulation AM W43.6 - ■
FM W 4 3.6 - .
3. PEP Power, Two Tone, SSB SSB Wpep 12 10.8 - :
4. Spuriouś & Harmonie Emission AM dB - 65 - 60
FM dB - 65 - 60
SSB dB - 65 - 60
5. Carrier Suppression SSB dB - 50 - 40
6. Current Drain (AC) at No
Modulation AM mA 300 700
FM mA 300 700
SSB mA 150 300
7. Current Drain (AC)
AM : MAX Mod. AM mA 300 700
FM : MAX Dev. FM mA 300 700
SSB : MAX Wpep,
Two Tone SSB mA 300 350
8. Modulation Frequency Response
(1kHz, 0 dB reference)
Lower at 450 Hz AM dB - 4 - 8
FM dB - 10 - 10
SSB dB - 4 - 8
üpper at 2.5 kHz AM dB - 4 - 8
FM dB - 5 - 10
SSB dB - 4 - 8
9. Microphone Sensitivity
AM : For 50% Mod. AM mV 12
FM : For ± 1 kHz Dev. FM mV 12
SSB : For 6 Wpep SSB mV 12
10. AMC Range & ALC Range
AM : 50-100 % Mod. AM dB 50 40

SSB : 9-13.2 Wpep SSB dB 50 40
11. Hum and Noise in Transmit
AM : 50 % Mod. AM dB 50 40
FM : For ± 1 . 5 kHz Dev. FM dB 40 30
12. Maximum Deviation FM kHz 2.7 3.5
RECEIVER
ITEMS MODE UNIT NOMINAL LIMIT
1. Max Sensitivity AM pv 0.50 1.5
SSB pv 0.25 0.50
2. Sensitivity
AM : For 10 dB S/N AM pv 1 2
FM : For 20 dB S/N FM pv 12
SSB : For 10 dB S/N SSB pv 0.25 0.50
3. AGC Figure of Merit 50 mV for
10 dB change in Audio Output AM dB 90 70
SSB dB 90 70
4. Overall Audio Fidelity
(6 dB down, 1 kHz ref.)
Upper Frequency AM Hz 2.000 1.500 ~ 3.000
FM Hz 2.500 1.500 - 4.000
SSB Hz 2.500 1.500 - 4.000
Lower Frequency AM Hz 250 200 ~ 500
FM Hz 250 100 ~ 500
SSB Hz 250 200 ~ 500
5. Distortion AM %2 7
FM %27
SSB %2 7
6. S/N Ratio at 1 mV Input AM dB 35 25
FM dB 40 30
SSB dB 40 30
7. Squelch Sensitivity at AM pv 12
Threshold FM W12
SSB pv 12
8. Squelch Sensitivity at Tight AM pv 1.000 250 - 4.000

FM V1V 1.000 250 - 4.000
SSB pv 1.000 250 - 4.000
9. S-Meter Sensitivity at "S—9" AM pv 100 40 - 250
FM pv 100 40 - 250
SSB pv 100 40 - 250
10. RF Gain Range AM dB 40 30
FM dB 40 30
SSB dB 40 30
11. Audio Output Power at Maximum AM V 3 2.5
FM W 3 2.5
SSB W 32.5
12. Audio Output Power at 10 % THD AM W 2.5 2
FM W 2.5 2
SSB U 2.5 2
13. Hi-Cut Effect at 2 kHz AM dB - 6 - 3
FM dB - 6 - 3
SSB dB - 6 - 3
14. Clarifier Range AM Hz ± 1.500 ± 600- ± 2.500
FM Hz ± 1.500 ± 600- ± 2.500
SSB Hz ± 1.500 ± 600- ± 2.500
15. Noise Blanker Performance (EIA)
AM dB 36
FM dB 36
SSB dB 36
16. ANL & NB Loss at ipV Input AM dB 82 -12
17. Current Drain at No Signal AM mA 100 200
FM mA 100 200
SSB mA 100 200
18. Current Drain
at MAX Audio Output
Power AM mA 150 300
FM mA 150 300
SSB mA 150 300
19. Dropout Voltage (AC) AM V130 175
FM V130 175
SSB V130 175
20. Image Rejection Ratio AM dB 80 70
(for ± 910 kHz) FM dB 80 70
SSB dB 80 70

21. Ist IF Rejection Ratio AM dB 80
(10.695 MHz) FM dB 80
22. 2nd IF Rejection Ratio AM dB 80
(455 kHz) FM dB 80
SSB dB 80
23. Adjacent Rejection (±1 0 kHz) AM dB 60
FM dB 70
SSB dB 70
E. GENERAL PERFORMANCE
1. Output Protection : Shall meet for 5 minutes for all VSWR's
(around the Smith Chart) of 20 : 1 without damage.
2. Output stability of all VSWR's (around the Smith Chart) of
up to 5 : 1 under continuous operation of a duty cycle of
5 minutes transmitting, and 1 minute receiving.
3. Reverse Polarity Protection : Shall hâve reverse polarity pro
tection and be operable with positive and negative grounding.
4. Standard Operating Température : -10°C ~ +55°C
5. Storage Température : -30°C - +70°C
6. Electrostatic Discharge Protection : Ail external case and
component parts shall withstand the application of 15 kV ESD
without causing failure or malfunction to the unit.
Test Conditions - Probe : 150pF with 500 û in sériés
Temp. : 25° C
70
70
70
70
70
50
60
60

II . ALIGNMENT PROCEDURES
A. CHECK OF FRONT PCB ASSEMBLY
1. Préparations
Front PCB Check jig
2. Conditions
SuppJy Voltage : 110 V 60 Hz
Unless otherwise specified, S551, 552, 553 and 554 shall be switched
OFF.
3. Procedure
STEP ITEMS TO BE CHECKED
1 Rotate CH rotary switch and check if CH LED's in ail channels from
CHI - CH40 are correctly displayed. Furtherraore, check if there
are no notable différences in luminance.
2 When S554 is switched "ON", check that "19" is displayed on CH LED.
3 Check that me ter lamp, PL551 and 552 are always turned ON.
Likewise, there should be no notable différence in luminance.
4Check that TX LED and RX LED are properly lit. When the jig's PTT
is ON, the TX LED should be ON and the RX and jig's PA LEDs should
be OFF. When the jig's PTT is OFF, the TX, RX and PA LED indicators
output will be reverse.
5When S551 is switched ON, check that the jig*s NB/ANL LED turns ON.
6When S553 is switched ON, check that the jig*s hi—eut LED turns OFF.
FRONT PANEL JIG
FC004 FC006 FC005

В . ADJUSTMENT POWER SUPPLY PCB ASS'Y
1. Préparations : Stabilized Power Supply (AC)
DC Voltmeter
2. Conditions : Supply Voltage : 220V 60 Hz (AC)
Probe Earth : TP10
3. Adjustment
STEF MODE MEASURING
DEVICÉ
CONNECTIONS
PT.S ТО
BE ADJ. PROCEDURE
1K.*
RX
Standby DC Voltmeter
to JP32.
VR801 Connect WA501 to power source
and switch power ON. Then
adjust so that DC Voltmeter
indication is 13.8 ± 0.1V.
VR801 is shown in Figure 4.
FIGURE 4
B801 PA—241
VR801