Ericsson 19D902783G1 User manual

TABLE OF CONTENTS
Page
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front Cover
GENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
CIRCUIT ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INPUT MATCHING NETWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
CRYSTAL FILTERS, IF AMPLIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
OSCILLATOR/MIXER/DETECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
AUDIO AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SQUELCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
BufferAmplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
High Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Noise Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
DCAmplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Schmitt Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
FAULT DETECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
VOLTAGE REGULATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
BLOCK DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RECOMMENDED TEST EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
ALIGNMENT PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ASSEMBLY DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
OUTLINE DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SCHEMATIC DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
PRODUCTION CHANGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
IC DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MAINTENANCE MANUAL FOR
25kHz RECEIVER IF MODULE
19D902783G1
DESCRIPTION
The MASTR III Receiver IF Module provides ampli-
fication and demodulation of the 21.4 MHz Intermediate
Frequency signal. The IF Module also includes the re-
ceiver squelch circuitry. However, it does not include de-
emphasis or squelch audio gating circuits. Figure 1 is a
block diagram showing the functional operation of the
IF Module.
The IF Module circuitry contains the following:
•A 50 ohm input impedance matching network and
IF Amplifier
•A chain of two crystal filters and two integrated
circuit IF amplifiers
•An integrated circuit containing a crystal
oscillator, mixer, limiter, and quadrature detector
•A variable gain AF amplifier
•A squelch circuit
•A fault detector circuit
•An integrated circuit voltage regulator
LBI-38643C
ericssonz
Ericsson Inc.
Private Radio Systems
Mountain View Road
Lynchburg, Virginia 24502
1-800-528-7711 (Outside USA, 804-592-7711) Printed in U.S.A.

CIRCUITANALYSIS
INPUT MATCHING NETWORK
The input impedance matching network provides a 50 ohm
load for the receiver RF module. The network consists of C1
thru C3, L1 thru L3, and R1.
Capacitor C1 provides AC coupling and a DC block on the
input line (J1). This DC block protects the module in the event
of a failure in a preceding module. L2 and L3 are series reso-
nant at 21.4 MHz and provide a signal path to the FET ampli-
fier Q6. Parallel resonant circuit, L1 and C2, provide a path to
the 50 ohm load, R1, for frequencies other than 21.4 MHz.
CRYSTAL FILTERS, IF AMPLIFIERS
Y1, Y2, U1, U2, and associated circuitry provide IF filter-
ing and amplification at 21.4 MHz. Filters Y1 and Y2 are both
4 pole bandpass filters with a center frequency of 21.4 MHz
and a bandwidth of ±6.5 kHz. Amplifiers U1 and U2 are inte-
grated circuit amplifiers. U1 provides 30 dB of gain, U2 pro-
vides 18 dB of gain. The amplifiers and filters have terminal
impedances of 50 ohms. In circuit gain measurements can be
made using a high impedance probe.
Inductors L3, L4 and associated resistors and capacitors
provide power supply decoupling. R3 and R7 provide paths to
the input of the Fault Detector circuit. These inputs enable the
Fault Detector circuit to monitor the DC voltages of U1 and
U2.
The RF level detectors consist of transistors Q1 and Q2
along with associated resistors and capacitors. These detectors
play no role in the normal operation of the IF Module, but they
aid in unit testing and module troubleshooting.
OSCILLATOR/MIXER/DETECTOR
Integrated circuit U3 provides several functions including
2nd mixer, if amplifier and limiter, and quadrature detector.
The 20.945 MHz crystal oscillator provides local oscillator
injection to the mixer in U3. This mixer converts the 21.4 MHz
IF signal to 455 kHz. C20 and C21 are oscillator feedback ca-
pacitors and have been chosen to provide the proper capaci-
tance for crystal Y3. The proper oscillator output level is
difficult to measure directly without affecting the oscillation.
A preferable measurement is at TP3 which should read
about 50 mV pk. (Measured using a 10 megohm, 11 pF oscil-
loscope probe.)
The mixer is internally connected to the crystal oscillator.
Pins 16 and 3 of U3 are the mixer input and output respec-
tively. Typical mixer conversion gain is about 20 dB. The out-
put of the mixer drives the 4 pole ceramic bandpass filter FL1.
The limiter input is U3 pin 5, but the limiter output is inter-
nally connected to the detector and is not externally available.
A received signal strength indicator (RSSI) is provided at
U3 Pin 13. This indicator signal is generated within the limiter
circuitry and provides an output current proportional to the
logarithm of the input signal strength. This current develops a
voltage across R18. The voltage varies from about 0.7 Vdc for
noise input, to about 1 Vdc for a 12 dB SINAD signal, to a
maximum of about 2.7 Vdc for a high signal level (50 dB
stronger than that required for 12 dB SINAD).
The quadrature detector provides a demodulated audio fre-
quency output. The input to the detector is internally connected
to the limiter and is not externally available. The output of the
detector is U3 pin 9. R19 and C28 provide low-pass filtering to
remove 455 kHz feedthrough. Ceramic resonator Y4 provides
the frequency selective component needed for FM demodula-
tion. Y4 replaces the typical LC resonant circuit found in most
quadrature detectors. In contrast to the typical LC network, Y4
requires no adjustment.
The DC supply to U3 is provided through voltage dropping
resistor R11 to U3 pin 4. R12 provides a path to the input of
the Fault Detection circuit. This enables the Fault Detector to
monitor the DC voltage on U3.
AUDIO AMPLIFIER
Operational amplifier U6.3 provides audio frequency am-
plification. Its gain is set by its associated resistors, including
variable resistor VR1. VR1 allows for adjusting the AF output
level to 1 Vrms with a standard input signal to the module (1
kHz AF, 3 kHz peak deviation). U6.2 is used as a voltage regu-
lator to provide 4 Vdc for biasing the Operational amplifier.
SQUELCH
BufferAmplifier
Integrated circuit U6.4 is configured as a unity gain buffer
amplifier. It provides a high input impedance to minimize load-
ing of the previous circuits.
Copyright© February 1992, Ericsson Inc.
TABLE 1 - GENERAL SPECIFICATIONS
ITEM SPECIFICATION
I.F. frequency 21.4 MHz
Input Impedance 50 ohm
12 dB SINAD -120.0 dBm
Adj. CH SEL (25 kHz) -103 dB
Image (20.49 MHz) -100 dB
3rd order Intercept Pt 23 dBm
Variation of Sensitivity with Signal Frequency 2 kHz
2nd I.F. frequency 455 kHz
2nd L.O. frequency 20.945 MHz
AF output (J2 pin 31C) 1 Vrms adjustable (with standard input signal)
AF output impedance 1k ohm
AF distortion 5%
AF response
10 Hz -3 dB
300 Hz ±1 dB
1000 Hz 0 dB reference
3 kHz ±1 dB
Hum & Noise -55 dB
RSSI output (J2 pin 20C) 0.7 to 2.7 Vdc prop to log (sig level)
RSSI time constant 5 ms
SQ Threshold Sensitivity -119 dBm
SQ Maximum Sensitivity -102 dBm
SQ Clipping 3 kHz
SQ Attack 150 ms
SQ Close 250 ms
SQ output (J2 pin 26C) 5V logic (low = squelched)
Fault output (J2 pin 11C) 5V logic (low = fault)
DC Supply 1 Vrms (adjustable)
LBI-38643C
1

Highpass Filter
The audio frequency highpass filter consists of U7.1 and its
associated circuitry. The purpose of this filter is to reject all
voice frequencies and allow only demodulated noise to pass.
The functioning of the squelch circuit depends upon the pres-
ence or absence of this noise. (When a signal is being received,
i.e. the receiver is quiet, the squelch circuit senses the absence
of noise and unsquelches the radio.)
Noise Detector
U7.2 along with associated components act as a noise de-
tector. The rectified output of U7.2 charges C44 to a nearly
constant DC voltage.
DC Amplifier
U7.3 is configured as a basic amplifier with a gain of 11.
Schmitt Trigger
U7.4 is configured as an amplifier with positive feedback.
This arrangement provides hysteresis in the output verses input
characteristic. This eliminates the possibility of the squelch cir-
cuit repeatedly cutting in and out when the input signal is near
a threshold. R56 and R57 act as a voltage divider to provide a 5
volt logic level output. (Logic High = unsqelched)
FAULT DETECTOR
U4 and U5 are voltage comparators. These are configured
into four "window detectors" which sense the presence of volt-
ages within specified ranges (windows).
The four window detector circuits are U4.1 & U4.2, U4.4
& U4.3, U5.1 & U5.2, and U5.4 & U5.3. These monitor DC
operating voltages on U6.2, U1, U2, and U3 respectively. R29
and R30 comprise a voltage divider to provide a 5 volt logic
level output. A fault is indicated when the output drops to zero.
Diode D1 and transistor Q3 monitor the output of the 8V
regulator. D1 is a 8.2 volt breakdown diode. If the regulator
output voltage should rise above 8.9 V (8.2 + 0.7 base-emitter
drop) Q1 will turn on and a fault will be indicated.
Transistors Q4 and Q5 are drivers for the front panel LED
CR1. These are powered from the +13.8 Vdc line before the
8V regulator. Therefore, if the regulator opens, a fault will still
be indicated.
VOLTAGE REGULATOR
U8 is a monolithic integrated circuit voltage regulator pro-
viding 8 Vdc. This powers all circuitry in the module with ex-
ception of the front panel LED and its drivers.
MAINTENANCE
RECOMMENDED TEST EQUIPMENT
The following test equipment is required to test the IF
Module.
1. FM Signal Generator; HP 8640B, HP 8657A, or
equivalent
2. AF Generator or Function Generator
3. Audio Analyzer; HP 8903B, HP 339A, or equivalent
4. Oscilloscope
5. DC Meter for troubleshooting
6. Power Supply; 13.8 Vdc @ 150 mA
ALIGNMENT PROCEDURE
1. Apply 13.8 Vdc supply to module.
2. Verify DC current consumption is between 90 and 150
mA.
3. Verify fault output is 0 to 0.5 Vdc and front panel LED
is off.
4. Apply a standard input signal to the module input. (-60
dBm, 21.4 MHz signal modulated with 1kHz AF, 3 kHz
peak deviation)
5. Set VR1 for 1 Vrms ±3% at module output (pin 31C on
96 pin connector J2).
Figure 1 - 25 kHz Receiver IF Module
LBI-38643C
2

TROUBLESHOOTING
Each IF amplifier has a nominal 18 dB gain. U2 has a
nominal gain of 30 dB. The mixer has about 20 dB gain with
proper LO injection. The proper crystal oscillator level is 50
mV pk measured at TP3.
The following four test points are provided on the PWB for
additional test capability:
TP1: 100 mV pk @ 21.4 MHz with -30 dBm input sig-
nal
TP2: 100 mV PK @ 21.4 MHz with -50 dBm input
signal
TP3: 50 mV pk @ 20.945 MHz independent of input
signal
TP4: 100 mV pk @ 455 kHz with -60 dBm input sig-
nal
All RF voltages measured with 10 Megohm, 11 pF probe.
ASSEMBLY DIAGRAM
TROUBLE SHOOTING GUIDE
SYMPTOM CHECK
(CORRECT READING SHOWN) INCORRECT READING INDICATES DEFECTIVE
COMPONENT
Fault indicator on Check DC voltages
+8V at U8 Pin 1
+4v at U Pin 7
5.5V at U1 output pin
3.3V at 2 output pin
4.4V at U3 Pin 4
If DC voltages not correct
U8 or associated components
U6 or associated components
U1 or associated components
U2 or associated components
U3 or associated components
If DC voltages correct
U4, U5, U6, D1, Q3, Q4, Q5
No audio - no
noise With no signal applied to module IF input Check for AF noise @ C29 ; 200mV
Check for AF noise @ U6 Pin 8: 1 V U3 or associated components U6 or associated components
Noise only - no
demodulated audio Check crystal oscillator: TP3 50 mVpk 20.945 MHz
Apply -30 dBm 21.4 MHz input, check TP1 100 mVpk
Apply -50 dBm 21.4 MHz input, check TP2 100 mVpk
Apply -60 dBm 21.4 MHz input, check TP4 100 mVpk
U3, Y3 or associated components
Q6, Y1, U1 or associated components
U2, Y2 or associated components
U3, FL1 or associated components
Poor 12 dB SINAD Check crystal oscillator: TP3 50 mVpk 20.945 MHz U3, Y3 or associated components
Apply -30 dBm 21.4 MHz input, check TP1 100 mVpk
Apply -50 dBm 21.4 MHz input, check TP2 100 mVpk
Apply -60 dBm 21.4 MHz input, check TP4 100 mVpk
Q6, Y1, U1 or associated components
U2, Y2 or associated components
U3, FL1 or associated components
No squelch
function With squelch pot maximum, or with module AUDIO/ SQUELCH/HI connected to SQUELCH/ARM input
and with no signal to module IF input:
Check Presence of 1 Vpk noise at U6 Pin 14 U6 or associated components
Check presence of 1 Vpk noise U7 at Pin 1
Check presence of 1 Vpk noise U7 Pin 1
Check DC voltage U7 at Pin 8: 7 V
Check DC voltage U7 Pin 14: 0.5 V U7 or associated components
RECEIVER IF MODULE
19D902783G1
(19D902783, Sh. 1, Rev. 3)
LBI-38643C
3

RECEIVER IF MODULE
19D902494G1
OUTLINE DIAGRAM
(19D902494, Sh. 1, Rev. 5B)
(19D902493, Comp. Side, Rev. 5)
LBI-38643C
4

SCHEMATIC DIAGRAM
RECEIVER IF MODULE
19D902494G1
(19D902504, Sh. 1, Rev. 6)
LBI-38643C
5

SCHEMATIC DIAGRAM
RECEIVER IF MODULE
19D902494G1
(19D902504, Sh. 2, Rev. 6)
LBI-38643C
6

PARTS LIST
SYMBOL PART NO. DESCRIPTION
R39 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R40 19B800607P332 Metal film: 3.3K ohms ±5%, 1/8 w.
R41 19A702931P285 Metal film: 7500 ohms ±1%, 200 VDCW, 1/8
w.
R42 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R43 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R44 19B800607P153 Metal film: 15K ohms ±5%, 1/8 w.
R45 19A702931P273 Metal film: 5620 ohms ±1%, 200 VDCW, 1/8
w.
R46 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R47 19B800607P563 Metal film: 68K ohms ±5%, 1/8 w.
R48 19B800607P822 Metal film: 8.2K ohms ±5%, 1/8 w.
R49 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R50 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R51 19B800607P334 Metal film: 330K ohms ±5%, 1/8 w.
R52 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R53 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R54 19B800607P223 Metal film: 22K ohms ±5%, 1/8 w.
R55 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R56 19B800607P181 Metal film: 180 ohms ±5%, 1/8 w.
R57 19B800607P821 Metal film: 820 ohms ±5%, 1/8 w.
R58
thru
R66
19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R67 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w
R68 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R69 19B800607P101 Metal film: 100 ohms ±5%, 1/8 w.
R70
thru
R74
19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R75 19B800607P391 Metal film: 390 ohms ±5%, 1/8 w.
R76 19B800607P100 Metal film: 10 ohms ±5%, 1/8 w.
R77 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R78 19B800607P392 Metal film: 3.9K ohms ±5%, 1/8 w.
R79 19B800607P272 Metal film: 2.7K ohms ±5%, 1/8 w.
R80 19B800607P750 Metal film: 75 ohms ±5%, 1/8 w.
R81 19B800607P121 Metal film: 120 ohms ±5%, 1/8 w.
- - - - - -INTEGRATED CIRCUITS - - - - - -
U1 344A3740P1 Silicon, bipolar.
U2 19A705927P1 Silicon, bipolar.
U3 19A149980P2 Linear: Osc./Mixer/IF/Det./Amp.; sim to
MC3372D.
U4
and
U5
19A704125P1 Linear: Quad Comparator; sim to LM339D.
U6
and
U7
19A701789P5 Linear:Quad Op Amp; sim to LM224D.
U8 19A704971P10 Voltage regulator: 8 Vdc;sim to
MC78M08CDT.
- - - - - - - - VARIABLE RESISTOR - - - - - -
VR1 19B800779P12 Variable resistor: 22k ohms, 0.1 w;sim to
Murata RGV4E223.
*COMPONENTS, ADDED, DELETED OR CHANGED BY PRODUCTION CHANGES
VHF RECEIVER RF MODULE
19D902783G1
ISSUE 2
SYMBOL PART NO. DESCRIPTION
- - - - - MISCELLANEOUS - - - -
2 19D902508P1 Chassis.
3 19D902509P1 Cover.
4 19D902555P1 Handle.
6 19A702381P506 Screw, thread forming: TORX, No.M3.5 - 0.6
X 6.
7 19A702381P513 Screw, thread forming: TORX, No.M3.5 - 0.6
X 13.
11 19A702381P508 Screw, thread forming: No.3.5-0.6 x 8.
Receiver IF Board
19D902494G1
- - - - - - - - - CAPACITORS - - - - - - - - - - -
C1 19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C2 19A702236P52 Ceramic: 120 pF, ±5%, 50 VDCW.
C3 19A702236P49 Ceramic: 91 pF, ±5%, 50 VDCW.
C4 19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C5
thru
C7
19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C8
thru
C10
19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C11
thru
C13
19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C14
and
C15
19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C16
thru
C18
19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C19 19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C20
and
C21
19A702061P47 Ceramic: 51 pF ±5%, 50 VDCW, temp coef 0
±30 PPM.
C22 19A702061P1 Ceramic: 1 pF ±0.5 pF, 50 VDCW.
C23
thru
C25
19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C26 19A702061P33 Ceramic: 27 pF ±5%, 50 VDCW, temp coef 0
±30 PPM/°C.
C27 19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C28 19A702052P5 Ceramic: 1000 pF ±10%, 50 VDCW.
C29 19A705205P5 Tantalum: 6.8 µF, 10 VDCW; sim to Sprague
293D.
C30 19A705205P2 Tantalum: 1 µF, 16 VDCW; sim to Sprague
293D.
C31 19A705205P12 Tantalum: .33 µF, 16 VDCW; sim to
Sprague 293D.
C32
thru
C34
19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW
SYMBOL PART NO. DESCRIPTION
C35 19A705205P2 Tantalum: 1 µF, 16 VDCW;sim to Sprague 293D.
C36 19A705205P5 Tantalum: 6.8 µF, 10 VDCW;sim to Sprague
293D.
C37 19A705205P2 Tantalum: 1 µF, 16 VDCW;sim to Sprague 293D.
C38
thru
C40
19A702061P89 Ceramic: 1500 pF ±5%, 50 VDCW, temp coef 0
±30 PPM.
C41 19A702052P22 Ceramic: 0.047 µF ±10%, 50 VDCW.
C42
and
C43
19A702061P77 Ceramic: 470 pF ±5%, 50 VDCW, temp coef 0
±30 PPM.
C44 19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C45
thru
C52
19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C53 19A705205P12 Tantalum: .33 µF, 16 VDCW;sim to Sprague
293D.
C54
thru
C58
19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C59 19A702052P5 Ceramic: 1000 pF ±10%, 50 VDCW.
C60 19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C61 19A702052P5 Ceramic: 1000 pF ±10%, 50 VDCW.
C62
thru
C67
19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C68 19A702052P5 Ceramic: 1000 pF ±10%, 50 VDCW.
C69
and
C70
19A702052P14 Ceramic: 0.01 µF ±10%, 50 VDCW.
C71
and
C72
19A702052P26 Ceramic: 0.1 µF ±10%, 50 VDCW.
C74 19A702061P49 Ceramic: 56 pF ±5%, 50 VDCW, temp coef 0
±30 PPM.
- - - - - - - - - - - - DIODES - - - - - - - - - - - -
CR1 19A703595P10 Optoelectronic: Red LED in right angle housing;
sim to HP HLMP-1301-010.
D1 19A700083P105 Zener: 8.2V; sim to BZX84-C8V2.
- - - - - - - - - - - FILTERS - - - - - - - - - - - -
FL1 19A702171P3 Bandpass Filter: Fc = 455 kHz, 6dB BW = ±7.5
kHz; sim to Murata CFU455E2.
J1 19A115938P24 Connector, receptacle.
- - - - - - - - - - - JACKS - - - - - - - - - - - - -
J2 19B801587P7 Connector, DIN: 96 male contacts, right angle
mounting; sim to AMP 650887-1.
- - - - - - - - - - -INDUCTORS - - - - - - - - - - -
L1
and
L2
19A700021P13 Coil, fixed: 470 nH.
L3
thru
L7
19A705470P35 Coil, fixed: 6.8 µH.
L8 19A705470P24 Coil, fixed:820 nH.
L9 19A700021P17 Coil, fixed: 1 µH.
SYMBOL PART NO. DESCRIPTION
- - - - - - - - TRANSISTORS - - - - - - - - -
Q1
and
Q2
19A704708P2 Silicon, NPN: sim to NEC 2SC3356.
Q3
thru Q5 19A700076P2 Silicon, NPN: sim to MMBT3904, low profile.
Q6 19A702524P2 N-Type, field effect.
- - - - - - - - - RESISTORS - - - - - - - - - - -
R1 19B800607P510 Metal film: 51 ohms ±5%, 1/8 w.
R2 19B800607P820 Metal film: 82 ohms ±5%, 1/8 w.
R3 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R4 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R5 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R6 19A702931P141 Metal film: 261 ohms ±1%, 200 VDCW,
1/8 w.
R7 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R8 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R9 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R10 19B800607P330 Metal film: 33 ohms ±5%, 1/8 w.
R11 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R12 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R13 19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R14 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R15 19B800607P182 Metal film: 1.8K ohms ±5%, 1/8 w.
R16 19A702931P369 Metal film: 51.1K ohms ±1%, 200 VDCW, 1/8
w.
R17 19A702931P261 Metal film: 4220 ohms ±1%, 200 VDCW, 1/8
w.
R18 19A702931P369 Metal film: 51.1K ohms ±1%, 200 VDCW, 1/8
w.
R19 19B800607P822 Metal film: 8.2K ohms ±5%, 1/8 w.
R20 19B800607P392 Metal film: 3.9K ohms ±5%, 1/8 w.
R21
and
R22
19B800607P272 Metal film: 2.7K ohms ±5%, 1/8 w.
R23 19B800607P332 Metal film: 3.3K ohms ±5%, 1/8 w.
R24 19B800607P182 Metal film: 1.8K ohms ±5%, 1/8 w.
R25 19B800607P392 Metal film: 3.9K ohms ±5%, 1/8 w.
R26 19B800607P272 Metal film: 2.7K ohms ±5%, 1/8 w.
R27 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
R28 19B800607P272 Metal film: 2.7K ohms ±5%, 1/8 w.
R29 19B800607P822 Metal film: 8.2K ohms ±5%, 1/8 w.
R30 19B800607P153 Metal film: 15K ohms ±5%, 1/8 w.
R31 19B800607P103 Metal film: 10K ohms ±5%, 1/8 w.
R32
and
R33
19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R34 19B800607P153 Metal film: 15K ohms ±5%, 1/8 w.
R35 19B800607P331 Metal film: 330 ohms ±5%, 1/8 w.
R36
and
R37
19B800607P104 Metal film: 100K ohms ±5%, 1/8 w.
R38 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
LBI-38643C
7

PARTS LIST & PRODUCTION CHANGES
PRODUCTION CHANGES
Changes in the equipment to improve performance or to simplify circuits are
identified by a "Revision Letter" which is stamped after the model number of the
unit. The revision stamped on the unit includes all previous revisions. Refer to
the Parts List for the descriptions of parts affected by these revisions.
Rev. A - 19D902494G1, 25 kHz IF Module Board
To improve performance in high temperature environments and to
eliminate Audio Level drifting, changed voltage regulator U8 and vari-
able resistor VR1.
U8 was: 19A704971P11, 8 Vdc;sim to MC78L08ACD.
VR1 was: 19A705496P5 20K ohms 0.1w; sim to Murata RGV4E203.
Rev. B - 19D902494G1, 25 kHz IF Module Board
To change Squelch Driver operation to allow compatibility with GETC,
changed resistors R56, R57, and R69.
R56 was: 19B800607P182 Metal film: 1.8K ohms ±5%, 1/8 w.
R57 was: 19B800607P822 Metal film: 8.2K ohms ±5%, 1/8 w.
R69 was: 19B800607P102 Metal film: 1K ohms ±5%, 1/8 w.
SYMBOL PART NO. DESCRIPTION
- - - - - - - - - - -CRYSTALS - - - - - - - - -
Y1 19A149974G7 Filter, crystal: Fc = 21.4 MHz, 3 dB BW =
15.0 kHz.Insertion loss = 2.0 dB max.
Y2 19A149974G8 Filter, crystal: Fc = 21.4 MHz, 3 dB BW =
15.0 kHz.Insertion loss = 3.0 dB max.
Y3 19A702284G5 Quartz crystal unit:20.945000 MHz ±10 ppm
@ 25°C.
Y4 19A149976P1 Fixed: 455 kHz.
LBI-38643C
8

IC DATA
U4 & U5
19A704125P1
Quad Comparator
U6 & U7
19A701789P4
Quad Op-Amp
U8
19A704971P10
Voltage Regulator
U3
19A149980P2
FM Receiver
U1
344A3740P1
Silicon Bipolar IC
U2
19A705927P1
Silicon Bipolar IC
LBI-38643C
9