PRELIMINARY INSTRUCTION BOOK

FOR

RADIO RECEIVER BC-225-Tl

AND POWER SUPPLY

RESTRICTED Of T[ H

NOT TO Bt 1AK£i• i'imM THIS ROOM

PREPARED AT

SIGNAL CORPS LABORATORIES

FORT MONMOUTH, NEW JERSEY

SEPTEMBER 28, 1936

INSTRUCTION BOOK

FOR

RADIO RECEIVER BC-225-Tl AND POWER SUPPLY

RESTRICTED

Notice:- This document contains intormation affecting the national defense of the United States within the meaning of the Espionage Act (u.s.c. 50:31,32). The transmission of this document or the revelation of its contents in any manner to any unauthorized person is prohibited.

The information contained in documents marked RESTRICTED will not be communicated to the public or to the press, but it may be communicated to any lmo"RRl to be in the service of the United States, and to persons of undoubted loyalty and discretion who are cooperating in governmental work. (AR 3.30-5)

Prepared at

SIGNAL CORPS LABORATORIES

FORT MONMOUTH, NEW JERSEY

September 28, 1936

TABLE OF CONTENTS Page

SECTION I. GENERAL DESCRIPTION

1. Radio Receiver BC-225-Tl•·••••••••••••••••••••••••••••••••• 1 A• Use•••••••••••••••••••••••••••••••••••••••••••••••••••• 1 £.. Frequency Bands•••••••••••••••••••••••••••••••••••••••• 1 £• Tubes........ . • . . . . . • • • . . . . • . . • • • • • • • • • • . • . . • • • • • • • • • • • 1 Current Values......................................... 1 e. Average Performance (Primary Power Source- 14 volts).. 2 2. Receiver Mounting.......................................... 2

J. Power Unit PE-( >·••••••••••••••••••••••••••••••••••••••••• 2 4. Cords and Remote Control Shafts............................ 2

Cord from Radio Receiver BC-225-Tl to Remote Control Box BC-( >••••••••••••••••••••••••••••••••••••••••·•••• 2

£_. Cord from Re.Ulote Control Box BC-( ) to Storage Battery. 2 c. Remote Tuning Shaft MG-124••••••••••••••••••••••••••••• 2

5. Component Parts............................................ 3

SECTION II. DErAILED DESCRIPTION

6. Radio Receiver BC-225-Tl ••••••••••••••••••••••••••••••••••• General Mechanical Features ••••••••••••••••••••••••••••

b. Controls ••••••••••••••••••••••••••••••••••••••••••••••• c. Cirelli t . ...................................... , ....... . Cords and Remote Control Shafts ••••••••••••••••••••••••••••

Cord from Radio Receiver BC-225-Tl to Radio Control !!:• Box BC-( )••••••••••••••••••••••••••••••••••••••••••••• Cord from Radio Control Box BC-( ) to Storage Battery •• Remote Tuning Shaft MC-124•••••••••••••••••••••••••••••

SECTION III. INSTALLATIO}l

8. General ••. •••. • • • • • • • • • • • • • • • · • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

SECTION IV. PREPARATION FOR USE

9. 10.

11. 12.

Insertion or Tubes ••••••••••••••••••••••••••••••••••••••••• Connection of Chassis to Power Supply and Control Box ••••••

Power Unit PE-( >••••••••••• • •••••••••••••••••••••••••• Radio Control Box BC-( )•••••••••••••••••••••••••••••••

Connection of Antenna and Ground••••••••••••••••••••••••••• Connection of Headphones•••••••••••••••••••••••••••••••••••

SECTION V. OPERATION

lJ. Tuning Procedure •••••••••••••••••••••••••••••••••••••••••••

SECTION VI. MAINTENANCE

14· 15. 16.

Getleral •• ••••.•• • •• •. • ... • ••••••••••••••••••••••••••.••••••• Location and Remedy of Faulte •••••••••••••••••••••••••••••• Fuses •••• • • • • • • • • • • • • • • • • •,• • • • • • • •' • • • • • • • • • • • • • • • • • • • • • • • •

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3 J 4 4 5

5 6 6

6

6 6 6 6 7 7

7

7 8 8

Page

APP.EN'DIX • •••••••••••••• • ••••••••••••••••••••••••••••••••• • •• , • i-iii

LIST OF ILLUSTRATIONS

Photographs

Fig. 1 -Complete Radio Receiver BC-225-Tl with Remote Control Unit Attached

Fig. 2 - Three-quarter Rear View of Chassis, Radio Receiver BC-225-Tl . Showing Power Unit Attached

Fig. 3 - Top View of Radio Receiver BC-225-Tl with Power Unit Attached

Fig. 4 - Three-quarter Front View of Radio Receiver BC-225-Tl Showing Remote Control Cables Attached

Fig. 5 - Radio Receiver BC-225-Tl Removed from Cabinet with Mounting Plate Attached

Fig. 6 - Remote Control Box BC-( )

Fig. 7 -Front View of Radio Receiver BC-225-Tl with Povter Unit PE-( ) Attached

Diagr,ams

Fig. 8 - Schematic Wiring Diagram, Radio Receiver BC-225-Tl

Fig. 9 - Cord Diagram, Radio Receiver BC-225-Tl

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PRELIMINARY INSTRUCTION BOOK

FOR

RADIO RECEIVER BC-225-Tl AND POWER SUPPLY

SECTION I

GENERAL DESCRIPTION

1. Radio Receiver BC-225-Tl •

.!• Use. Radio Receiver BC-225-Tl is of the metal-tube, integral-coil superheterodyne type, intended for aircraft and vehicular use where remote control is required. It provides reception of modulated (phone-tone) signals over the frequency band or 190-400 , 2500-8000 kc when connected to a primary d-e source (storage battery) whose voltage is 11 to l4 volts. It eliminates the necessity tor using plug-in coil sets by including all necessary coils in a compact form inside the receiver.

J2_. Frequency Bands. The spectrum or 190-400 , 2500-8000 kc is covered in four bands without the use of plug-in coil sets and is divided as follows:

Band Nominal Frequency Band 1 190-400 kc 2 2500-3700 kc 3 3700-5500 kc 4 5500-8000 kc

S• The tollowing types of metal tubes are employed:

Position 1st r.r. lst detector (mixer) R-f oscillator 1st i.f. 2nd i.r.. 2nd detector and lst

audio amplifier AVC amplifier Audio amplifier

Current Values.

Type or Tube 6K7 6L7 6C5 6K7 6K7

6q'f 6J7 6F6

Filaments: approximately 2.8 amperes at 12.0 volts Total plate: 50 ma at 220 volts Total dynamotor and filament current without heaters:

4.15 amperes at 12 volts 4.65 amperes at l4 volts

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Total dynamotor and filament current wi. th heaters: 5.85 amperes at 12 volts 6.65 amperes at 14 volts

Average Performance (Primary Power Source - 14 volts).

(1) Sensitivity.

(a) Manual volume control; tone reception: approximately 5 microvolts input for 10 milliwatts output over the frequene.y range

kc . Approximately 10 microvolts input for stated output over the range 190-4UO kc.

(b) Automatic volume control; tone reception: approximately 5 microvolts input for 10 milliwatts output over the frequency range 2500-8<. kc. Approximately 10 microvolts input for stated output over tr . 190-400 kc.

( 2) Selectivity.

(a) Band width not greater than 19 kc at a ratio of 10 to 1.

(b) Band width not greater than 30 kc at a ratio or 100 to 1.

(c) Band width not greater -than 52 kc at a ratio or 1000 to 1.

2. Receiver Mounting. A special frame has been designed to flexibly mount the Radio Receiver BC-225-Tl. This frame attaches to the BC-225-Tl wi tJl four snap fasteners which are opera ted from the side of the receiver.

3. Power Unit PE-( ). This is a totally inclosed nni t, size 6-3/ 4" x 7-7 /16" x 4", provided with a special plug permitting direct attachment to the radio receiver without the use of an auxiliary cord. When the power unit is in place, the receiver length is increased 3-1/811 • One cord connecting to the remote Control Box BC-( ) is required. This unit supplies all the high-voltage powP.r required by Radio Receiver BC-225-Tl. It operates on 11-15 volts d.c.

4. Cords and Remote Control Shafts.

!.• Cord from Radio Receiver BC-225-Tl to Remote Control Box BC-( } • This is a special seven-conductor shielded cable terminating in a Plug PL-98 on the dynamotor end and a Plug PL-98 on the receiver end.

:Q.. Cord from Remote Control Box BC-( ) to Storage Batter,y. This is a seven-conduct-or shielded cable terminating in Plug PL-S9 on the dynamotor end and two battery clips on storage-battery end.

£• Remote Tuning Shaft MC-1?4_. Two remote Tnning Shafts MC-124 are required to connect from Radio Receiver BC-225-Tl to the remote

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Control Box BC-( ). These are ten feet long and are similar to those £urnished with Radio Set SCR-183.

5. Component Parts. The component parts are as follows:

1 Radio Receiver BC-225-Tl (complete with tubes)

1 Receiver mounting frame 3 Tubes, RCA 6K7, 1-1/2 oz ea. 1 Tube, RCA 6C5, 1-1/2 oz ea. 1 Tube, RCA 6Q7, 1 oz ea. 1 Tube, RCA 6J7, 1-1/2 oz ea. 1 Tube, RCA 6F6, 1-1/2 oz ea. 1 Tube, RCA 6L7, 1-1/2 oz ea. 1 Power Unit PE-( )

Size Length Height Depth

in. in. in.

8-1/2 x 8-3/4 x 12-7/8 (Overall) 8 x 1-1/8 x 11 (Overall)

3-1/8 x 1-5/16 Dia. 2-5/8 X 1-5/16 Dia. 3-1/8 x 1-5/16 Dia. 3-1./8 X 1-5/16 Dia. 3-1/4 x 1-5/16 Dia. 3-1/8 X 1-5/16 Dia.

6-3/4 x 7-7/16 x 4 (Overall) 1 Cord, BC- 225-Tl to Control

Box BC-( ) 10' 4-1/211 1 Cord, Control Box BC-( )

to Storage Battery 6' O" 2 Remote Tuning Shafts MC-124,

BC-225-Tl to remote Control Box BC-( ) 10' 1"

1 Control Box BC-( ) 9-l/2 x 3-5/8 x

Total weight of complete receiver

SECTION II

DETAILED DESCRIPTION

6. Radio Receiver BC-225-Tl •

8-1/4 (Overall)

Weight lbs.

19.25 1.10

.282

.094

.094

.094

.094

.094 8.25

2.10

3.70 5.50

4]..00

.!.• General Mechanical Features. The thought of compactness and sturdiness hes paramotmt in the_design of this receiver. At the same time certain components such s.s i-f and r-f transformers have beer made as detachable integral assemblies. Thus the separate units may he

permitting rapid test of components and quick inspection . dur:tng either production or repair. Further, in to secure the ma:r.:).'11U"1 of frequency stability the complete r-£ oscillator assembly is in a shielded, heat-in:nuated compar'bnent end mo.L'ltained at a temperature o£ 120 degrees F. Air-trimmer condensers are used .exclusivt-ly to insure that the maximwn of frequency stability is secured. 'J.Tnese air trimmers may be locked in place once they have been set, thus vibration and jarring should not impair receiver performance or necessitate frequent readjustment. While the use of air triromers of this type results in a considerably larger receiver than can be constructed using leaf-type mica

the disadvantage of increased size is eiilply repai u.

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.Q.. Controls.

(1) This receiver has been especially designed for entirely remote operation. The main tuning dial is located in the Control Box BC- ( ) and turns by means or a flexible Tuning Shaft MC-124 the vari bl condenser located in the radio receiver. A 100 to 1 gear reduction e empl oyed t o f acilitate resettability. 8

(2) Band Changing. The band-changing mechanism is operated the remote control box by means of a flexible shaft connecting to th f r om mechru1ism located the cabinet. An especially des· ed indicating device is provided remote Control Box BC-( enable the unused portion of the dial to be hidden fro on any of the four bands selected for reception. The electrical mi,iew is such that the r-f oscillator, 1.st r.f. and 1st detector por ti c l'CUit simul ta.neously connected to the proper bands grounding all are Thi s latter precaution bas been taken to eliminate aU. tendency t COils. "dead spots" due to absorption. owa.:x-ds

(3) OFF-MANUAL-AUTO Switch. This switch, located in th Control Box BC-( ), permits selection of either manual volume automatic volume control as as set off and on. It or located t o the left of the tunmg dial and is identif· l.s panel engraving OFF-MAN-AUTO. This switch is the only OFF-oN co by the provided and t urns on tpe filaments and the "B 11 supply when the ;11ANUAL or AUTO position. e to ei th

(4) Volume Control. A dual potentiometer is provid d signal attenuation to secure the optimum results on both manu:r for high control and automatic volume control by means of a special c' is locatea t o the right of the main calibrated ttming dial. It

.£• Circuit.

(1) General. The circuit is of the superheterod for either manual or automatic volume control. It type adapted for preselection, a special image rejection coupling network r-r stage detector, an r - f oscillator, ·two intermediate-frequency am first a diode second detector with means for securing automatic (470 kc)

ri th the first audio amplifier incorporated within thun.e control , an AVC amplifier and fl. final audio stage of amplification. e same tube,

· (2) Antenna Input. The antenna-input ci"rcuit ma: b . two parts, an inductively coupled antenna transformer and e into rejection circuit of the "Wheeler" type. This image-rej image-included only in the three upper bands. In the lowest frequ is intermediate-frequency wave trap is also included. Tile and an that the ant enna tracking is satisfactory for any antenna betw 200 mu mu f with the use of external trimmers once the hand been made. n as

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(3) Radio Frequency Stage. The r-£ stage is of the inductively c?upled, tuned-grid t,rpe, employing a 6K7 vacuum tube, ganged and tuned

both the oscillator and first detector stages. The automatic-volume-control voltage is applied to the grid return in such a manner that it does not interfere with the normal biasing secured by means of a "H. V." bleeder. Thus effective control of radio-frequency sensitivity is secured.

(4) First Detector (Mixe..cl_. The tube employed in this stage, a 6L7, is particularly suitable for use as a mixer, especially at high frequencies. The stage comprises a variable tuned-grid circuit, inductively couf .. led to the r-f amplifier stage, and a fixed tuned-plate circuit, coupled into the first i-f transformer. Grid bias is provided by means of a voltage-bleeder resistor and automatic-volume-control voltage is applied to the grid.

(5) Radio Freguengy Oscillator. This stage employs a 605 tube i n & modified Hartley circuit, directly coupled to the injector grid of the mixer tube. It is tracked with both the r-f amplifier stage and the first detector stage.

(6) Intermediate Frequency .Amglifiers·. The circuits for these amplif"iers are essentially the same, employing 6K7 tubes in a tuned-grid tuned-plate arrangement. The rrequency employed is 470 kc. The input to the first of the two amplifiers is inductively coupled from the mixer

Iron-core intermediate-frequency transformers are employed. The gB.lll of both stages is controlled by the automatic-volume- control volta.ge, and fixed bias i s secured by means of a voltage bleeder. In addition, tne cathode of the first i-f tube is. returned to the variable portion of' the r-r cathode resistance and hence varied simultaneously, permitting manual control of sensitivity.

(7) Second Detector and First Audio Ampli£ier. This stage employs a duo-diode triode tube of the 6Q7 type, utilizing the diode pl ates for i-f detection and the triode portion for audio amplification.

(8) Automatic Volume Control System. This stage employs a sharp cut-of£ triode tube of the 6J7 inductively coupled from the last i-f transformer by means of a third winding isolated from the normal

channel. By maintaining the plate of this tube it l. s possible to secure improved au tom a tic volume control nth 't?e mmJ.lllUlll of complication. The bias is 80 adjusted that delayed automatJ.c volume control starts at approximately 60-mw output. The time constant on phone signals is approximately 1/10 of a second.

7 Cords and Remote Control Shafts.

Cord from Radio Receiver BC-22 -Tl to Radio Control Box BC-This cord, 10 reet in length, comprised of' Cordage CO-( , carries the terminations already mentioned under General Description.

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•

£_. Cord from Radio Control Box BC-( ) to Storage Battery. This cord, six feet in length, comprised of Cordage C0-120, carries the terminations as already mentioned under General Description •

.£• Remote Tuning Shaft MC-1?4. See section I, paragraph 4, of GeneraJ Description.

SECTION III

INSTALLATION

8 General. The receiver installation is largely determined by the requirements and choice of position desired. Attention is invited to the fact that radio Control Box Be-( ) has twin terminations on opposite sides which will permit the tuning shafts and remote-control cable to enter where most convenient.

SECTION IV

PREPARATION FOR USE

9 Insertion of Tubes. The following tubes must be placed in the sockets which bear like identification:

Function R-f oscillator lst r.f. lst detector (mixer) 1st i.f. 2nd i.f. 2nd detector and 1st

audio amplifier AVC amplifier Audio amplifier

'lype of Tube 6C5 6K7 617 6K7 6K7

6C[l 6J7 6F6

10 Connection of Chassis to Power Supply and Control Box.

!!• Power Unit PE-( ) • Attach this power supply directly to the receiver cabinet by means of three threaded studs projecting from the front panel of the receiver. This requires removal of the front cover of the power wit. When in place, the power unit is electrically connected to the receiver by means of the special plug in corpora ted within the shielded housing. Attach the remote-control cable into the socket located on the bottom of the Power Unit PE-( ) .

£. Ra.dio Control Box BC-( ) • Connect the other end of the cable previously attached to the Power Unit PE-( ) to either of the input sockets of the Control Box BC-( ). Attach one Tuning Shaft MC-124 to

the radio receiver outlet marked "Tuning" and to the input s pline on the control box, taking care that the alignment of the tuning condenser on the receiver and the tuning dial on the control box correspond in the following manner: With the tuning condenser of the receiver at the minimum position, the calibrated dial located in the remote-control position should indicate the highest frequency on Band #1. A pointer is provided on the variable condenser to indicate when the condenser is set at this position. A window is provided in the receiver cabinet to permit installation with the receiver in its housing. The remote "Band Change" shaft is attached to the remaining two spline outlets which correspond to the position for Band #1. (When removing this remote shuft, care should be taken to always turn the band-change mechanism to #1 position.) Attach the battery cable to the socket located in the bottom side of the control box, connecting the ends with terminals to a source of voltage between 11 and 15 volts.

11 Connection o£ Antenna and Ground. Attach an antenna to the post marked ANT whose capacity does not exceed 200 mu mu f maximum or 50 mu mu f minimum, connecting a ground wire to the post marked GND.

12 Connection of Headphones. Insert a pair of headphones or a loud speaker into the phone jacks whose impedance does not depart materially from the range 1500 to 7000 ohms for maximum power transfer •

SECTION V

OPERATION

13. Tuning Procedure •

.!!:.• Set the tuning dial to the frequency desired as indicated by the calibrated dial on the remote control box. This may involve rotation o£ the band-change swltch to secure the wanted frequency.

b. Select the type of reception desired by turning the switch . . marked OFF -MANUAL-AUTO to the proper position. If set to the AUTO pos1 t1 Ol t J

automatic volume control results. In either position the action is to light the dial light and filaments, at the same time starting the "B" power supply •

.£.• Adjust the volume control by turning the knob mtil a satisfac-tory signal is obtained.

SECTION VI

MAINTENANCE

1.4. General. A periodic check of the equipment should be made to insure satisfactory performance. Each tube should be checked at regular

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intervals either by a tube checker or by interchange vd. th a tube known to be satisfactory. Filament batteries should be checked regularly and replaced when the potential has decreased to 11 volts. The antenna and ground system should be checked and inspected for loose connections, etc.

15. Location and Remedy of Faults.

Test all tubes on tube checker. The following average charac-teristics apply:

6K7 6L7 6C5 6Q7 6J7 6F6 Heater voltage 6.3 6.3 6.3 6.3 6.3 6.3 Heater current 0.3 0.3 0.3 0.3 0.3 0.7 Plate voltage 250 250 250 250 100 250 Screen voltage 100 100 100 250 Grid voltage -3 -3 -S -2 -3 -16.5 Plate current 7 5.3 8 0 .5 2 34 Screen current. 1.7 5.5 0.5 6 Plate resistance 800,000 800,000 100,000 1 Meg. 800,000 Amplification factor 1160 20 1185 200 Mutual conductance 1450 1100 2000 1185 2500 Load resistance - 200,000 7000 Max. overall length 3-1/811 3-1/811 2-5/8" 3-1/811 3-1/8" 3-1/4" Max. diameter 1-5/1611 1-5/1611 1-5/1611 1-5/1611 1-5/1611 1-5/16"

Q• Check all voltages at the tube socket by means of a high-resis-tance voltmeter. If normal, the following voltages will be noted when using the Po\orer Unit PE-( ) viith 14 volts input on MVC. All grid voltages measured at voltage divider.

Position Tube Plate Screen Filament Grid Jit..; 1st r.f. 6K7 215 94 7.0 1st detector (mixer) 617 222 82 7.0

R-f oscillator 6C5 (225 No. 4)

7.0 -(166 Band No. 3)-(16o Band No. 2)

70 Band No. 1 1st i.f. . 6K7 218 92 7.0 2nd i.f'. 6K7 215 94 7.0 2nd detector and 1st

audio amplifier f:/:[1 160 7.0 AVC amplifier 6J7 -2.4 -24 7.0 Audio amplifier 6F6 218 225 7.0

* At divider

Attention is invited to the f'act that the filaments are connected in series-parallel across the low-voltage line.

16. Fuses. Two fuses are provided in the Power Unit PE-(), one

-3.0 -3.0

-3.0 -J.O -2

-60* -24

a general fuse for the radio receiver chassis, rated at 10 amperes and the other f'or the dynamotor alone rated at 5 amperes.

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Fig. 1 - Complete Radio Receiver BC-225-Tl with Ranote Control thit Attached

Fig. 2 - Three-quarter Rear View of Chassis, Radio Receiver BC-225- Tl Showing Power Unit Attached

_I

Fig. 3 - Top View of Radio Receiver BC-225-Tl with Power Unit Attached

r.;-..

Fig. 4 - Three-quarter Front View of Radio Receiver BC-225-Tl Showing Remote Control Cables Attached

Fig. 5 - Radio Receiver BC-225-Tl Removed from Cabinet with Mounting Plate Attached

(' SIGNAL CORPS US ARMY -POWER UNIT PE-

PART OF RADIO SET SCR-AT CO"PIS U9C"Af01111(1

FCIH .. l .. ,'l"a(f OI'ICEA!4C ra.rt t-•J·)O ttAI&LMO•

SIGNAL C0RPS LABORATORIES 'O>rTY -.wcutH '

Fig. 7 -Front View ot Radio Receiver BC-225-Tl with Power Unit PE- ( ) Attached

PiRTS LIST OF BC-225-Tl CHASSIS

Qa,pacitors 01 10-100 mu mu t C2 50 mu mu t C3 10-50 mu mu t C4 100 mu mu t C5 10-75 mu mu f C6 100 mu mu r C7 10-75 mu mu t Cg 100 mu mu t 09 10-100 mu ·mu r C1o .01 mu t ell 256 max. , 13 min. C12 .OS mu t · c13 10-50 mu mu r 014 100 Diu r c15 10-75 mu mu r c16 100 mu mu r o17 10-75 mu mu r C18 100 mu mu r C19 10-100 mu mu t C20 .05 mu t 0:21 .01 mu t c22 256 max., 13 min, c23 .us mu r c24 .os mu t 025 C26 250 mu mu t 027 · 10-100 mu mu t 028 .01 mu r C29 10-100 mu mu t 030 10-100 mu mu t o31 .01 mu t 032 .01 mu t c33 .01 mu t c34 .os mu t C35 10-100 mu mu t c36 10-100 mu mu t c37 .01 mu t c3a .05 mu t c39 .001 mu t 040 .01 mu t

.01 mu .r 0'42. .05 lllU t 043 .os mu t 044 .os mu r 045 .os lllU t 046 .05 mu t· C47 .05 ruu t C48 .as .mu t

Capacitors

Coils Ll L2 L3 L4

L9 L1o L11

L12 L13 Ll4 L15 L16

L17 11s

.05 mu t 5689 mu mu r 3694 mu mu r 2584 mu mu r 10-140 mu mu r 100 mu mu t 10-100 mu mu t 100 mu mu t 10-100 mu mu r 100 mu mu r 10-75 mu mu t 10-50 mu mu r 100 mu mu t 256 max.; .13 min. .01 mu r .002 mu t 1.0 mu r

Audio jack

1500 mu h S75 mu h 16.0 mu h 3-1/4 turns #2SE, 11/1611 dia.,c1ose wounJ 89 mu h 2-1/4 turns #2SE, 11/16" dia. , close wound 3.8 lllU h 2-J./2 turns #28E, 7/16" dia., oloee woW1d 12 turns #20E, 374" dia. 16 turns per inel1 16-1/4 turns #20E, 1" dia. 20 turns

per inoh turns #2SE, l" dia. 40 turns

per inoh 2385 mu h 3.6 mu h 5.1 mu h 5.4 mu h ll-1/2 turns #20E, 3/4" dia. 16 turna

per inch 15.8 turne #20E, l" dia. 20 turna per

inoh 20-l/4 turns #28E, l" dia. 40 'blrns per

inch

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Coils L19 2325 mu h L20 21.5 turns #28E, 7/16" dia., close wound L21 12 turns #28E, ll/16" dia., close wound L22 15 turns #28E, 11/16" dia., close wound L23 190 mu h L24 6.1., turns #20E, 1" dia., close wound, center tapped L25 12.4 turns #20E, 1" dia. 20 turns per inch, center tapped L26 20 turns #28E, 1" dia. 24 turns per inch, center L27 437 mu h, 2 secondaries, equal inductance, spaced 3/16 128 L29 700 mu h L30 400 mu h L31 1200 mu h 132 1200 mu h L33 1200 mu h L34 1200 mu h L35 1200 mu h

Resistors R1 100,000 ohms, 1/2 watt

. R2 1,000 ohms, 1/2 watt R3 100,000 ohms, 1/2 watt R4 350 ohms, 1/2 watt R5 30,000 ohms, 1/2 watt R6 1000 ohms, 1/2 watt R7 100,000 ohms, 1/2 watt Rg 1000 ohms, 1/2 watt R9 100,000 ohms, 1/2 watt R1o 10,000 ohms, 1 watt R11 10,000 ohms, 1 watt R12 1000 ohms, 1/2 watt R13 1 Meg., 1/2 watt R14 1 Meg., 1/2 watt R15 100,000 ohms, 1/2 watt Rl6 100,000 ohms, 1/2 watt R17 100,000 ohms, 1/2 watt R1g 75 ohms, 1/2 watt R19 750 ohms, 1 watt R2o 500 ohms, 1 watt R21 50 ohms, 1/2 watt R22 6 ohms, 40 watts R23 15 ohms, 3 watts R24 40,000 ohms, 1/2 watt R25 15,000 ohms, 1/2 watt R26 10,000 ohms, 1/2 watt

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Switches swl 1st r.f. SW2 Image rejection circuit

Mixer sw4

Oscillator

T1 Output transformer

THS1 Heater thermostat

-iii-

c ...

WrTC.H POfHT N tiW&C:.R$:

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- Seb.eme:'\:a...e 1.'\.a.di.o Reeei.ver BC-225-Tl

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APPARATUS LEGEND: CAPAC ITO RS :

c. - - I 0 - I 0 0 M M "'· c2

_ _ 50 MMF.

c3 __ 10-SOM<vq•. _ _ I00MM"·

Cs - _I0- 75MMI". c

6 __ too ... ..., .. .

C y -- 10 - 15M ... F· c8

_ _ too ...... ,. . Cg-- 10.-IOOMMI'. C

10 __ .o t .....

C., - _ t2. -2b4MMF. C,2 _ _ .0.5MP, G,!>- _10-50 MMF.

c,4

_ _ 100 ........... C

1, __ 10-15MMF.

C10

__ 100 MMI'.

C,-, -- \0-15 MMF.

c,8 __ too ""M"· C,g __ tO-IOOM\J\1'.

Czo- -. 0.5 """· C:u--· 0'""'"·

Cu - _ 12- Z b4 """""· C 2 !> __ ,.05 MF.

C ... __ .05MF.

_ eso MM" Cz.7-- 10-100 MMP.

C.u- _ . 01 M"· Cz.g--10-IOOMMF C:so- - 10-100"""'"·

C 32.- . 01 MF ·

G 33 - - • 0 \ M I' ·

.05MF.

c 3, __ lo-loo"""""· C37 - _. 01 c!>\1 -- .os,., ... C 39 __ .OOh•F . C,.0 _ _ .QI ..,,., C4l- - .01 Ml',

C•z. - _ .OS,.,,, C4!>- - .05MF.

L,, __ Is. a r. • zoe: . ,. o lA .?OT. "· '· L,a- _Z0 1/4 T.*Z6E. I"DIA .40T.P.t

_ 2.!>25 J" ·i-1· 7

,, Lz -- ZI.ST. " Z.SE.I,, DIA . C.L WD.

0 ,,, .. L __ IZT. "Z8E. lib DIA . CL.WO.

;Lj II/ ol

1.5T . ..,2.8E . tit. DIA. CL.WD. L n --190.1':' ..... L

24 __ 6,4T.*20E I "D\A.(LWO. <.EI.J.TAP.

LZ!J- _ 12.4 T lf20E I'' DIA. 20 T . "·'· C. EN. TAP. 201. 11 26E I " DIA . 'Z.4T,P, o CEN . TAP.

1.-. 27 __ 437 ,...h. 2.S£C.. EQI)AL \NPIJ( . .!>PA<.EO'lJ,"

c •• -_ .os.., ... __ .05MP.

c.b--C+7- _ ,05 MF·

C,.e,-- .Q5..,F. C49 __ .05MF. C50 • _ 5b89 """""· (. 51 __ 3o94MMf'· C52 __ esa4 ... ..,F.

10- 140M>1P. C 54- - 100 11 ..,,

C 55 __ 10-/00•u.,·.

Cs1- . 10-100 MMF.

(.58- . 100 "'MF.

C59 -- 10-15MMF, C.&O - - I 0 -5 0 M M F.

col-- 100 MMF.

C.62 - - I 2- 2. 6 + M "'" C63 - - . 0 I t'\ F. C 6"' __ .oo 2. ..,., , C 65 __ l, Q..,F.

R, __ IOO.OOO..n. '12.W R 2 __ I,OOO..a...

_ 100,000 .n. R4- _ .n.. R s- _ 30,000 ..n.. R 6 __ I,OOO..n. R 7 • _ 100.000 .,'l-R11 __ I OOO..n... R 9 __ I OO,OOO..n. R '<'- _ 10,000-n. I W R 11 . _ 10 ,000.1'\.. R 12.- _ I.OOO..n.. 'hW. R ,-, .. I MEu. R , .. . _ I ME(, R l 5 - _ IOO, OOO..n. R 111 •• 100,000..0.. R11 -- IOO, OOO..n.. R 1e - - ?S ..n. R 111 • _ 150.n.. I w

- 500 .I"- I W , 50.1"- 'lz W .

J, __ AUDIO JACK

CO IL5'. L, - _ 1500/'.h. Ll _ _ 8 7 s l"·n.

_ 16.0 .,,h. L

4 __ .5/"-r. 11 Z.8E. '1/u.," DtA. CL . WD.

Ls-- 6.9/"h Lo-- 2 T. "28 DIA. C. L. WD. L 7 __ 3.8/" h . La -- 2.'/zT. "'2!3 E.. DIA. CL .WD L, __ 12T. •20E . !>I.4 ' DIA . 16T.P.I.

L 16'' DIA. 20T.P. 1• •o-- '"' · t.. 11 __ 20'/4 T."2.8E I" DIA

L 1a-- 2.385/'.h, L •!>- _ .?>. 6 /"'. h. L,4 __ 5.1 _.M. h· L. •s-- 5.+, "'.1-. . L,&-- 11/'aT. "2.0E.31 • .,"DIA. lbT. P.I

Ru -- 6.n.. R 13 __ 15..n.. RH __ 4-0,00 0 .fl.

Rls-- 15,000.n.. IO. OOO_n..

AO w 3W 't2 w.

_ _ R . F 5Wz. - I MAC.£ REJECTION

5W4[

__ 05C.COMPARTMfNT

T, __ _ OUTPUT

C.IR.

HEATER.

THS, . I-IEAT E. R

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r- - ----- -- ---- --- --- ------ --- -- , POWER UNIT PD- I

I I I I

I

' f I :-Ill __ .

t.SOV ' t : I I

' I 1------- -APPARATU5

t4"CAPAttTOft ,., ......... .)A fi-----··• IOA FU.$f

.J, • .JK- 30 PHONf .JAC.K

C .. ,}···· PilOT LAMP lM1

_ ....... _ AUOIO PLUG

I I I I I I

' I 1'._ J - ---------

LEGEND: R, ... .... ........ l MEC:I Y'a.W, "a.··· ......... .soo, ooo..n

Y.,.W, R:4 ... -- ....... . ao.ooo .A. A5 .... . ........... 2.4A. lOW. R., . . .............. lO W

5W, ............ ...

CO•

W.AI'tOON '" II

OI..ACI< • t+

WtHTt. • t+ <tiU:E.N ••a

PL-.9& YE.LLOW • I&

---- ----- -- -- -----

lt£0• 16 IU.C\C • l A. DLAC.K • t• - !4' WtUTe. • t•

co- :: &ltOWif •I& ........ _,.,

Pl.-&e .5HieLO • l>hiE.LP

CONTROL 80)( 8C-

Fig. 9 - Cord Diagram, R&dio Receiver BC-225-Tl