LTV G-187 User manual

INSTRUCTION BOOK
FOR
MODEL G-187 SPECIAL PURPOSE RECEIVER
LTV - Electrosystems, Inc.
(A Subsidiary of Ling-Temco-Vought)
TEMCO Aerosystems Division
P.O. Box 1056
Greenville, Texas 75402

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WARNING
This equipment employs voltages which are dangerous and may be fatal if
contacted by operating personnel. Extreme caution should be exercised
while working with this equipment with any of the protective covers removed.
NOTICE
This is not the original Istruction Manual of the LTV G-187 Receiver,
it is only an attempt to write one from scratch (but for sure it is very
close to the original manual however). It is based upon visual
inspection and visual circuit tracing on an existing and unmodified
LTV G-187 Receiver that has survived and upon the Instruction Manuals
of some Nems-Clarke units using similar components.
The work is dated 2010-2011 and the author is Paolo Viappiani
of La Spezia, Italy ([email protected]), a radio collector whose
only purpose was to share information on this particular unit.
It is a no-profit work and consequently in no way this manual may be sold
and/or made object of commercial transactions.
The work is still in progress, so any contribution and suggestion
is very welcome. The author also apologizes for eventual ad unwanted
mistakes, misprints or omissions of which he cannot be held as responsible.
La Spezia, Italy, March 2011

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TABLE OF CONTENTS
Paragraph Page
WARNING & NOTICE………………………………………………………. 2
SECTION 1 - GENERAL DESCRIPTION
1. PURPOSE OF EQUIPMENT............................................................……… 11
2. DESCRIPTION OF EQUIPMENT...................................................……… 11
SECTION 2 - THEORY OF OPERATION
1. ANALYSIS, MODEL G-187 RECEIVER……………………………………15
2. “MASTER” AND “SLAVE” RF TUNERS.......................................………...16
a. Antenna Inputs ..................... ...................................................... ………..16
b. First RF Stage ("Master or "Slave" Tuner)……………………………….16
c. Second RF Stage ("Master" or "Slave" Tuner)…………………………...17
d. Mixer ("Master " or "Slave" Tuner)............................................ ………..18
e. Local Oscillator ("Master" Tuner Only) ..................................... ………..18
f. Oscillator Buffer ("Slave" Tuner Only)...................................... ………...19
3. IF STAGES .................................................................................……..…19
a. Function Switch in 200 Kc. FM Position, Master IF Channel……………19
b. Function Switch in 200 Kc. AM Position, Master IF Channel…………...20
c. Function Switch in 200 Kc. FM or AM Position, Slave IF Channel……..20
d. Function Switch in 40 Kc. FM Position, Master IF Channel…………….20
e. Function Switch in 40 Kc. AM Position, Master IF Channel......……….21
f. Function Switch in 40 Kc. FM or AM Position, Slave IF Channel………21
4. OTHER CIRCUITS .....................................................................……….22
a. Video............................................................................................……….22
b. Squelch.........................................................................................……….22
c. Audio Amplifier...........................................................................……….24
d. Carrier Operated Relay (COR).....................................................……….24
e. Power Supply ............................................................................................26
f. Signal Strength and Tuning Meters............................................................27
SECTION 3 - OPERATION
1. INTRODUCTION ............................................................................. ………..28

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2. CONTROL SETTINGS ...................... ..............................................………..28
a. Power .........................................................................................………....28
b. Function Switch...........................................................................................28
c. Squelch.........................................................................................................28
d. Audio Gain....................................................................................................28
SECTION 4 - MAINTENANCE
1. INTRODUCTION........................................................................... .................29.
2. IF ALIGNMENT PROCEDURE (Sweep Method)
a. General Instructions........ .................. .......................................................30
b. Equipment Required . ................................................................………..30
c. Control Settings ............................... .......................................... ………..30
"Master" 200 Kc. IF Channel Alignment...........................................................31
d. Second Limiter, Adjustment of T-507........................................………..31
e. Discriminator, Adjustment of T-508 ..........................................………..31
f. First Limiter, Adjustment of T-505 and T-506 .........................………..31
g. Second IF Amplifier, Adjustment of T-503 and T-504 ............. ………..31
h. First IF Amplifier, Adjustment of T-501 and T-502 ..................………..31
"Slave" 200 Kc. IF Channel Alignment..............................................................32
d. Third IF amplifier, Adjustment of T-307 and T-308..................………..32
e. Third-Second IF amplifier, Adjustment of T-305 and T-306.... ………..32
f. Second IF Amplifier, Adjustment of T-303 and T-304 .............………..32
g. First IF Amplifier, Adjustment of T-301 and T-302 ..................………..32
"Master" 40 Kc. IF Channel Alignment.............................................................33
d. 40 Kc. Band-Pass Filter, Adjustment of L-606 and L-607.......................33.
e. 2.5 Mc. IF Amplifier...................................................................………..33
"Slave" 40 Kc. IF Channel Alignment................................................................34.
d. 40 Kc. Band-Pass Filter, Adjustment of L-602 and L-603........………..34
e. 2.5 Mc. IF Amplifier...................................................................………..34
3. LOCAL OSCILLATOR ADJUSTMENTS ........................................………..34
a. Local Oscillator Adjustment, "Master" RF Tuner only..............………..34
b. Mechanical Adjustments ............................................................………..34
4. RF AMPLIFIER ALIGNMENT………………………………………….…....35
a. RF Amplifier Alignment............................................................. ………..35
5. IF ALIGNMENT (CW Method) ......................................................... ………..36
a. Introduction................................................................................. ………..36
"Master" 200 Kc. IF Channel Alignment............................................. ………..36
b. Second Limiter Alignment - (CW Method)................................ ………..36

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c. Discriminator Alignment - (CW Method) .................................. ………..36
d. IF Amplifiers - (CW Method)......................................................………..36
"Slave" 200 Kc. IF Channel Alignment................................................ ………..39
b. Third IF amplifier, Adjustment of T-307 and T-308.................. ………..39
c. IF amplifiers.......................................…………………………………...39
"Master" 40 Kc. IF Channel Alignment.............................................................40
b. 40 Kc. Band-Pass Filter, Adjustment of L-606 and L-607.......................40
c. 2.5 Mc. IF Amplifier................................................................... ………..40
"Slave" 40 Kc. IF Channel Alignment................................................................41
b. 40 Kc. Band-Pass Filter, Adjustment of L-602 and L-603........ ………..41
c. 2.5 Mc. IF Amplifier................................................................... ………..41
SECTION 5 - PARTS LIST
a. Parts List...................................................................(currently under construction)
DISCLAIMER…………………………………………………………………… 75
LIST OF ILLUSTRATIONS
Figure Title Page
1-1 Model G-187 Special Purpose Receiver, Front View……………………. 7
2-1 Block Diagram, Model G-187 Receiver ........................................……… 14
2-2 Receiver Squelch Circuit, Simplified Schematic........................... ……… 23
2-3 Receiver COR Circuit, Simplified Schematic................................ ……… 24
4-1 Model G-187 Receiver, Top View (Dust Cover Removed)........... ……… 44
4-2 Model G-187 Receiver, Bottom View (Dust Cover Removed) .... ……… 45
4-3 Model G-187 Receiver, Rear View ............................................... ……… 46
4-4 Model G-187 Receiver, Panoramic Top View (Cover Removed)………... 47
4-5 Model G-187 Receiver, Panoramic Top View Left Side (C. R.)…………. 48
4-6 Model G-187 Receiver, Panoramic Top View Right Side (C. R.)………… 49
4-7 Model G-187 Receiver, Panoramic Bottom View (C. R.)………………… 50
4-8 Model G-187 Receiver, Panoramic Bottom View Left Side (C. R.)……… 51
4-9 Model G-187 Receiver, Panoramic Bott. View Right Side (C. R.)……… 52
4-10 Model G-187 Receiver, Large Component Board……………………….. 54
4-11 Model G-187 Receiver, Small Component Board………………………. 55
4-12 Model G-187 Receiver, Auxiliary & Output Circuits (Top View)……… 55
4-13 Model G-187 Receiver, Auxiliary & Output Circuits (Bott. View)…….. 55
4-14 Model G-187 Receiver, Auxiliary & Output Circuits (Bott. View)……. 56

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4-15 Master & Slave RF Tuners, Bottom View (Covers Removed)…………. 57
4-16 Master & Slave RF Tuners, Panoramic Bottom View (C. R.)…………. 58
4-17 Master RF Tuner, Bottom View (Cover Removed)………………………. . 59
4-18 Slave RF Tuner, Bottom View (Cover Removed)………………………….. 60
4-19 21.4 Mc - 200 Kc. BW IF Strip, Top View…………………………………. 61
4-20 21.4 Mc - 200 Kc. BW IF Strip, Bottom View……………………………… 61
4-21 21.4 Mc - 200 Kc. BW IF Strip, Bottom, Input Side…………………………62
4-22 21.4 Mc - 200 Kc. BW IF Strip Bottom, Output Side………………………. 62
4-23 2.5 Mc - 40 Kc. BW IF Strip, Top View……………………………………. 63
4-24 2.5 Mc - 40 Kc. BW IF Strip, CEI Label…………………………………… 63
4-25 2.5 Mc - 40 Kc. BW IF Strip,B.P.Filter Details……………………………. 63
4-26 2.5 Mc - 40 Kc. BW IF Master Channel Bottom View……………………. 64
4-27 2.5 Mc - 40 Kc. BW IF Slave Channel Bottom View……………............... 64
4-28 Controls in the Front Panel (Bottom Side)………………………………… 65
4-29 AGC “MON/DF” and Function Switches, Front Panel……………………. 65
4-30 Front Panel Function Switch, Rear View………………………………….. 65
4-31 AGC “MON/DF” Rotary Switch, rear View………………………………. 66
4-32 Power Supply Section, Top View………………………………………….. 66
4-33 Power Supply Section, Bottom View………………………………………. 66
5-1. Schematic Diagram: Master RF Tuner……………………………………… 67
5-2 Schematic Diagram: Slave RF Tuner………………………………………. 68
5-3 Schematic Diagram: 21.4 Mc.- 200 Kc. BW IF Strip………………………. 69
5-4 Schematic Diagram: 2.5 Mc.- 40 Kc. BW IF Strip………………................. 70
5-5 Schematic Diagram: Main Chassis Circuits………………………………… 71
5-6 Schematic Diagram: Mainframe…………………………………………….. 72
5-7 Schematic Diagram: Power Supply Circuits………………………………… 73
5-8 Schematic Diagram: Various Details…………………………………………74
LIST OF CHARTS AND TABLES
Table Title Pages
1-1 Performance Specifications ............................................................ ………. 8
1-2 Semiconductor and Tube Complement ......................................... …… 9, 10
4-1 Voltage Measurements, Model G-187 Receiver..............................…… 42, 43
5 Parts List............................................................(currently under construction)

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Figure 1-1. Model G-187 Special Purpose Receiver, Front View

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PERFORMANCE SPECIFICATIONS
Model G-187 Receiver
Tuning Range 55-260 Mc.
IF Rejection 70 dB, minimum
Image Rejection 58 dB, minimum
Noise Figure 6 dB, maximum
Absolute Sensitivity 4 uV produces at least 23 db S/N with 100 kc deviation, 1 kc
modulation frequency.
IF Frequencies 21.4 Mc. and 2.5 Mc.
IF Bandwidth 200 Kc and 40 Kc
FM Output 0.10 Volt per Kc, approximately
AM Outputs,
200 Kc and 40 Kc strips Approx. 10V RMS for 500 uV input modulated 50% at 1 Kc.
FM Output Stability Varies less than 2 dB for inputs above 1 uV.
AM Output Stability
200 kc and 40 kc strips 7 dB maximum variation for 40 dB variation in input.
Input (Ant.) Impedance Approx. 50 Ohms.
Video Response 10 Cps to 300 Kc
Power Input 115 VAC, 50-60 Cps (400 Cps on special order);
28 V (DC or AC) for front panel lamps.
Power Consumption 170 Watts
Weight 40 lbs.
Power Input connector: 12-pole round male DEUTSCH, “DS” Series (12-0), J-106;
Output connector: 19-pole round female DEUTSCH, “DS” Series (19-0), J-108.
Table 1-1. Performance Specifications

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Table 1-2. Semiconductor and Tube Complement.

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Table 1-2. Semiconductor and Tube Complement (continued).