GE 4EX16A10 User manual

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SPEGIFICATIOTS
Input Power
Input Voltage
Output Voltage
Impedance
Input
Output
Amplifier Gain (t2%)
Input
Amplif ier
HF Probe
Temperature Range
One rnilliampere at L4 volts
(two ?-vo It mercury batteries)
5 volts maximum
t5 voLts maximum
150, O0O ohms
25 ohms
Xl, XlO and X50
DC to 2A kHz
5 MIIa to 5OO MHz
o"c to 45"c (32'F to llg"F)
the use of the servicemqn. Refer to the qppropricte Specificotion Sheet for the complefe

LBr -4097
TABLE OF CONTENTS
SPECIFICATIONS . ... Cover
DESCRIPTION
OPERATION
CIRCUIT ANALYSIS
MAINTENANCE ... I
Disassembly .... 1
Battery Replacement .... 2
Troubleshooting Procedure z
Gain Adjustment Procedure 3
CALIBRATION PROCEDURE
OUTLINE AND SCHEMATIC DIAGRAM
Test Amplifier .
RF Probe
5
7
PARTS LIST
PRODUCTION CHANGES
TYPICAL LOGIC AND SCHEMATIC DIAGRAM FOR IC-l
L1

DESCRIPTION
General Electric Test Amplifier Model
4EX16A1O uses a single Integrated Circuit
module for operation as a high impedance m
amp Ii f ier . lYhen used wi t h RF Probe
19C3 1137OG1, the Test Amplifier can be corl-
nected to Test Set Models 4EX3A1O & 11 (or a
standard multimeter) to function as a high-
sensitivity RF voltmeter.
The amplifier and probe are designed
for measuring the gain of receiver front end
and IF circuitsr oscillator injection volt-
ages, and for measuring RF leve1s in other
RF circuits. The amplifier may also be used
for amplifying low level audio signals.
OPERATION
All operating controls and the input
and output binding posts are conveniently
Iocated on the front of the amplifier. The
binding posts are spaced for use with a dual-
banana plug if desired.
GAIN SELECTOR
Gain selector switch SlOOl selects the
Xl (unity) , X10 and X5O amplif ier ranges,
and also turns the amplif i.er on and of f .
BAI"ANCE
Balance potentiometer R1OOZ is used to
set the 4EX3A1O (or multimeter) on zero be-
fore maklng measurements. with the Test set
and RF Probe connected to the anplifier and
the gain selector on X5O, R1O02 is adjusted
for zera meter reading on the Test Set or
multimeter.
ATTEI\TUATOR
Attenuator RlOOl controls the input
level to the Test Amplifier. To obtain
actual gains of XI, X10 or XbO, Rl0O1 must
be turned fully clockwise to the CALTBRATE
position.
References to symbol numbers mentioned
in the following text may be found on the
appricable outline Diagrailr schematic Dia-
gram or Parts List (see Table of contents).
CIRCUIT ANALYSIS
TEST AMPLIFIER
The basic amplifier circuit consists
of Integrated Circuit module IC-I and 8s-
LB I _40978
sociated circuitry mounted on printed wiring
boards A1OO1. IC-I is a high performance,
operational amplifier whose gain is con-
trolled by three feedback circuits. The
feedback circuits are selected by GAIN switch
S10O1. Resistors RB and R9 form the Xl
(unity) feedback loop; resistors R6 and R7
form the X10 feedback loop, and R4 and R5
form the X50 feedback loop. Instructlons
for setting potentiometers R5, R7 and R9 are
contained in the Maintenance section of this
manual (see Tab1e of Contents).
The input is coupled through ATTENUATOR
R1OOI and a voltage divider network (nf and
R2) to terminal 5 of the IC. The output is
taken from terminal 10 and applied to the
feedback loops and the output terminal.
Battery voltage (L4 volts) is applied to the
IC through terminals 11 (+) and 6 (-).
Terminal 4 connects to ground through R3.
A small difference in potential called
the "offset" voltage is present at terminal
10 regardless of the input voltage applied
to IC-l. This voltage can be cancelled out
by BAI"ANCE potent iometer R1002 so that the
Test Set or multimeter can be set on zeta.
Instructions for setting the BAI"ANCE control
are contained in the OPERATION section of
the manual as listed in the Table of Con-
tents.The amplif ler may also be used f or 8fi1-
plifying audio signals in the DC to z0-kEz
range. The audio frequency response of the
amplifier at the different gain levels is
shown in Figure 1.
RF PROBE
RF Probe 19C31137OG1 is a highly sen-
sitive, uncalibrated probe for detecting RF
s ignals in the 5-MIIZ to 500-MHz range .
Point-contact diodes are used in the probe
for better sensitivity. A curve showing
the frequency response of the probe is shown
in Figure 2.
The probe is terminated in a dual-ba-
nana plug that connects to the Test Amplifier.
The probe may also be connected directly to
a rc oscilloscope for checking RF levels.
As an aid to the servi.ceman in trouble-
shooting RF clrcuits, a calibration proc€-
dure is provided for calibrating the RF
Probe (see Table of Contents).
TIAIilTENANCE
DISASSEMBLY
To disassemble the amplifier for s€r-
vicing, remove the two Phillips-head screws
in the front of the nameplate and carefullyI

C IRCUIT ANALYSI S
FREQUENCY IN HERTZ
Figure 1 Test Amplifler Audio Frequency Response
l.o lo
FREQUENCY IN MHZ
Figure 2 - Frequency Response of RF
roo
Probe
slide the amplifier chassis out of the case. CAUTION
LBI -4097
2420
-2
-4
-6
BATTERY REPLACEMENT
To replace the battery, disassemble
the amplifier as directed in the procedure
above, and remove the old batteries. In-
stall the new batteries (Mallory TR-165 or
equivalent ) with the f lat end (+) toward
the + marked on the battery holder.
Do not dispose of mercury bat-
teries by burning as the bat-
teries may explode.
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TROUBLESHOOTING PROCEDURE
I[henever the BAI,ANCE
set the Test Set of zero,
rooo
control will not
or the gain po-
zooo | +ooo
3000 5000

tentlometers cannot be set for the proper
voltage readlngs , flrst check the appllcable
potentlometer. If the potentlometers are
operatlng properlyr r€place fC-l.
To replace the fC, cllp off all of the
leads as close to the body of the module as
posstble. Then unsolder and remove one lead
at a tine, belng careful not to put the
prlnted wtrtng pattern away from the board.
GAIN ADJUSTX{ENT PNOCEDUNE
If potentiometers R5, R7, R9 or fC-I
are ever replaced, lt will be necessary to
readjust R5, R7 and R9. Adjust the poten-
tiometers aceording to the following pro-
cedure :
EquipTnent Requlred
l. An audio oscillator with a lOO-IIz output.
2, An AC-VWM.
Procedure
I. Connect the audio oscillator and the
VT\IM to JtOOl and JIOOZ on the Test
Amplifier.
2. Turn R1O01 on the Test Amplifier fully
LBr -4097
clockwlse to the CALIBRATE positioor
and place the GAIN control in the XI
pos 1t lon .
3. Apply a lOO-Hz, .04-vo1t RMS signal to
the ampllf ler.
4. Now connect the VTVM to output j acks
J10O3 and JLOO4 on the Test Amplifier,
and adJust R9 for a meter reading of
. 04 vo lt m{S.
5. P1ace GAIN control Sl0Ol to the X10
positlon and adJust VI for a meter
readlng of O.4 volt FUUS.
6. Place GAIN control SIOO1 in the XsO
posltlon and adjust R5 for a meter
reading of 2.O volts RMS.
CATIBRATIO]I PROCEDURE
If desired, the output of the RF Probe
can be callbrated in millivolts. Calibrate
the probe as follows:
Equipment Required
1 . Signal Generator (U-560 or equ j-va len t )
with a Type N male to BNC female adapt-
or and a Type BNC Tee cotlnectof , and a
50-ohm load.
2. Test Amplifier and RF Probe.
UAINIENANCE
GE TEST SET
'mr,,sw'l
9
ffi
SIGNAT GENERATOR
:cL
:@
offi
TYPE ''N" MALE
TO TYPE BNC
FEMALE ADAPTOR
TYPE BNC
TEE.CONNECTOR
RF PROBE
50-oHM
LOAD TEST AMPTIFIER
Figure 3 - Calibration Test Set-Up

LBI -4097 MAINTENANCE
130
t20
ilo
too
90
80
70
60
50
40
30
20
to
3. GE Test Set Mode1 4EX3A1O or equivalent
mult imeter .
Pfocedure
1. Terminate one end of the I'Tt' connector
directly into a 50-ohm load (no cable) ,
and connect the RF Probe directly into
the unterminated end as shown in Figure
3.
2. Place the Test Set on the I-volt scale
and set the amplifier GAIN control in
the X5O positj.on.
3. Adjust the BAI,ANCE control for zero
meter reading, and turn the ATTENUATOR
control fully clockwise to the CALIBRATE
posltion.
4
2.O 2.2 ?.4 2.6 2,8
Adjust the signal generator output for
a meter reading of 0.1 volt on the Test
Set. Then record the millivolt reading
directly off of the signal generator.
Increase the signal generator output in
L/LO-volt steps and record the millivolt
readings. The readings can be plotted
on graph paper as shown in Figure 4.
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DC OUT PUT VOLTAG E
Figure 4 - TVpical Calibration Curve for RF Probe
4.
5.
TThenever three or f our of the read-
ings fall in a straight line in-
dicating that the output ls in-
creasing in a linear fashion with
the input (normally between I volt
and 1.6 volts). The straight line
may be continued to complete the
curve without further measurements.

OUTTINE DIAGRAM
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ON / OF F GAIN CONTROL
(198219054, Rev.1)
J toor
OUTPU T I NPUT
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SCHEMATIC DIAGRAM
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PL 198216390G I I
(PRINTED WIRINGU
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W-BK-R g;o t5s
6S
(19C3L7238, Rev. 2)

SCHEMATIC DIAGRAM
LBI-409?
NOTES:
I . A LL WIRES ARE S F24 EXCEPT AS
NOTED.
2. DA= #22 AWG WIRE SIZE.
3. ALL SIOOI CONNECTIONS ARE TO B
SECTION UNLESS OTHERWISE SPECIFIED.
Jto03
Jtoo4
ALL RESISTORS ARE I /2 WATT UNLESS
OTHERWISE SPECIFIED AND RESISTOR
VALUES IN CHMS UNLESS FOLLOWED BY
K= IOOO OHMS OR MEG = I.OOO.OOO OHMS ,
CAPACITOR VALUES IN PCOFARADS (trUAL
TO MICROMICROFARADS} UNLESS FOLLOV1IED
BY UF= MICROFARADS. INDTJCMNCE VALUES
IN MICROHENRYS UNLESS FOLLOWED BY
MH= MILLIHENRYS OR H= HENRYS.
IN ORDER TO RETAIN RATED EOUIPMENT
PERFORMANCE, REPLACEMENT OF ANY
SERVICE PART SHOULD BE MADE OryLY WITH
A COMPONENT HAVING THE SPECIFlCATIONS
SHOWN ON THE PARTS LIST FOR THAT PART.
SCHEMATIC & OUTLINE DIAGRAMS
TEST AMPLIFIER MODEL
I ssue 3
4EX16410
@Il-- AMPL'XFgorBoARo-l
5
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PL t982t6390c I I
( PRTNTED WtRtNG) |
SEE APPLICABLE PRODUCTION CHANGE
SHEETS IN INSTRUCTION BOOK SECTION
OEALING WITH THIS UNIT, FOR DES.
CRIPTION OF CHANGES UNDER EACH
REVISION LETTER.
THIS ELEM DIAG APPLIES TO
Rtoo3
IK
(19C3L7238, Rev.2)

LBT-4097 PRODUGTIOI{ CHANGES
Changes l-n the equipnent to lnprove perfornance or to stnlltfy clrcults
are identtfied Ui " I'RevLsion Letteri', whlch ls stanped after the nodel
number of ttre unit. The revislon stanped on the unit lncludes all pre-
vlous revislons. Refer to the Parts Llet for descrl'ptlons of parts af-
fected by these revlsions.
REV. A To improve anpllfier stabllity.
Added CI and R1OO3.
Y
PARTS LIST
LBr-4126C
TEST A"UPLIFIER IODEL 4EX16A1O
AND
BF PR,OBE I9C311370G1
SYMB()L GE PART T{0. DESCRIPTIOTI
AlOOI
cI*
I coIPisrENT BOARD
| 1eB2t63eoc1
| - - cAPAcrrGs
I -ff nv-.5r v
7489162P31 | Sitver mlca: 15O pf t5%, 5OO YDC[; slm to
I Electro lotlve'Type DF.I5. Added by REV A.
ICl 19A116297P1
3R77PL24J
3R77P82&t
3e77P755J
198209358PL15
3R77P155J
198209358P112
3R77p913J
198209358PI-O8
5492L74PL
198209238P1
198209238P2
198209238P1
LsB2os238P2
B8
R9
Bt'f1001
and
8T1002
J1001
J1002
J1003
J1004
lRl
l*,
I and
lns
l*n
l*u
l:;
QreratLonal AryIlfler: Ionollthlc; sln to
Fairchlld pA74LC.
a Crrt/lD G
Conpositlon: O.L2 negohm +5%, I/2 v.
Composltlon: 82,OOO ohms +5%, L/2 v.
Cornposltlon: 7.5 negohns t5%, L/2 Y.
Varl.able, carbon f llm: approx SOOO to 5 negohns
!2O%, O.25 v; sln to CfS Type X-2O1.
Couposltlon: I.5 negohrs t5%, L/2 v.
Varlable, cerbon flln: approx 2OOO to 1 negobn
+2O%, O.25 v| sln to CIS Type x-2O1.
Conpositlon: 91,OOO ohns +5%, L/2 Y.
Yarlable, carbon flln: appTox 1@ to SOTOOO
ohms tlO%, O.25 r; sln to CTS Type X-2O1.
Iercury z 7 v; slm to lallory Type Tt-I65
;;; ;""., "x, :";:::T"'; ;; ;,
Bindlng post: BLack, L5 aqr; sin to HX fulth
r517.
Blndlng post: Red, 15 aql; sLn to EH Snlth 15t.7
Blnding post: Black, 15 eqt; sln to ffi Snlth
1517.
Rl001
Rloo2
R1003*
s1001
xBflool
and
xB[roo2
19A116306P2
19A116306pl
3R77PLOzJ
Varlable, ca^rbon fllrnt SOOTOOO obns +N%t L/6 t
to CIS Serles 2OO.
YarLable, carbon flln: IO,OOO ohns +2O%t L/4 ti
sln to CtS Serles 2OO.
CoryosltLon: 1OOO ohns t5$, l/2 v. Added by
REV A.
19C311370Gl
L9AL227L9PL
19A116296P1
r98205453Gl
4037aO3P2
. - IISCELLAITEOUS
RF Probe. Includes 19A127381P1 spring.
Knob. (Used wlth SlOOl).
Knob. (Used wltb BlOOl and RIOO2).
f,ouslng.
CALIMATI$T CG{NE TORS
(Not Part of Test Arylifler)
Adapter, coaxial: slm to Type ,N'r to rr$lCrr
I9C3O?O6OP.[ | not"ry: 2 sectiou, 4 posltlon, 6 polesl sln to
I qns 2zz-L72s4-2.
I
l-- --scx'rs-
198216684cr I *rt""y holder.
I renare UCr-2OIA,/U.
777657opr.L I m;;r, coaxLal: sln to Tlpe "B{c" TEE
*COITNPONENTS ADDED, DELETED OR CHANGED BY PRODUCTION CHANGES.
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LBT-4097
(19C31757O, Rev. f)
SCHEMATIC DIAGRAM
RF PROBE 19 C3 1 1 370 Gl
OPTION 4382
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TYPICAL LOGIC & SCHEMATIG DIAGRAMS
OPERATI ONAL AMPLI FI M 19A 1 16297 PL
8 Issue I

LBr -4097
ORDERING SERVICE PARTS
Each component appearing on the schematic diagrarn is identified by a symbol number, to sim-
plify locating it in the parts 1ist. Each component is listed by symbol number, followed
by its description and GE Part No.
Service Parts may be obtained from Authorized GE Communication Equiprnent Service Stations
or through any GE Radio Communication Equipnent Sales Office. I[hen ordering a part, be sure
to give:
1. GE Part Number for component
2. Description of part
3. Model number of equipment
4. Revision letter stamped on unit
These instructions do not purport to cover aI1 details or variations in equipment nor to
provide for every possible contingency to be met in connection with installation, operation
or maintenance.
\ Should further information be desired, or should particular problems arise which are not
covered sufficiently for the purchaser's purposes, contact the nearest Radio Conmunication
Equipment Sales Office of the General Electric Company.

\
MAINTENANCE MANUAL
LBT-4097
U
ts
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MOBI LE RADIO DEPARTMENT
GENERAL ELECTRIC COMPANY O LYNCHBURG, VIRGINIA 24502
PRINTED IN U.S.A. GEil ERAL @ ELECTRIC