August 1940 Radio-Craft
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
|
Unlike even the vacuum tube type AM radio
in the dashboard of my parents' car in the early 1960s that were self-contained
units, even earlier radios designed for cars and trucks had their bulky
electronics mounted under the sea or in the trunk, with a remote volume and
tuning control mounted in the dashboard. That greatly complicated the
installation as well as the design of the radio. This circa 1940 Belmont Model
678 Auto-Radio is a prime example. Note the unique cylindrical shape of the
radio chassis, and that the remote control is a pushbutton assembly with
rotating knobs for tuning and volume. Operating from a 6 volt DC car
battery (12 volts came later), these radios required a "vibrator" circuit to
convert DC to AC (and back to a higher level DC) in order to transform to a
couple hundred volts for the plate voltage of the tubes.
Belmont Model 678 Auto-Radio Set Radio Service Data Sheet
6-Tube Superhet.; 6-Button Automatic Remote
Tuner Unit; Automatic Volume Control; Range 535 kc. to 1,565 kc.; Synchronous-Type
Vibrator; Single Stud Mounting.
Fig. 1. Complete schematic diagram of the Belmont model 678 auto-radio receiver.
Fig. 2. Chassis view showing locations of trimmers and components.
Fig. 3. Bottom view of remote tuner
Fig. 5. Belmont auto-radio model 678. Note Remote Tuner at right.
Alignment Procedure
Turn volume control to maximum for all adjustments. Connect radio chassis to
ground post of signal generator with a short, heavy lead. Connect dummy antenna
in series with generator output lead;- 0.1-mf. for the I.F. band and a 125 mmf.
for the broadcast band. Use an output meter across the primary of the output transformer.
Allow chassis and signal generator to heat up for several minutes.
I.F. Alignment
Feed a 465-kc. signal to the grid of the 6SK7 I.F. tube. Set dial at 1,400 kc.
Adjust trimmers C19 and C20 for maximum output. To align this output I.F. unit without
using cathode-ray oscilloscope, a 10,000-ohm resistor must be shunted across the
diode tuned circuit as indicated by points X and Y on the schematic (Fig. 1) and
in Fig. 4. Trimmer C19 is identified by a red dot on top of the I.F. can.
Fig. 4. Bottom view of chassis giving socket voltages.
After alignment of these 2 trimmers, remove the 10,000-ohm resistor and align
trimmer C21 for maximum output. Do not readjust trimmer C19 or C20 after the resistor
has been removed. Shift the signal generator lead to the control-grid of the 6A8
and adjust trimmers C14 and C15 for maximum output.
Broadcast Band
Feed a 1,565-kc. signal to the antenna lead with the set dial adjusted to 1,565
kc. Adjust trimmer C5 for maximum output. Reset the dial to 1,400 kc. and adjust
trimmers C1 and C3 for maximum output using a 1,400-kc. test signal. Finally, reset
the dial to 600 kc. and adjust trimmer C2 using a 600-kc. test signal in the antenna
lead. Maximum gain for this adjustment depends on the capacity of the antenna system
of the car in which the radio receiver is installed.
Power consumption is 7.7A. at 6.3V. No suppressors required on the spark plugs;
only a distributor suppressor is needed. The output I.F. coil has 3 tuned circuits
giving superior band-pass qualities and selectivity as compared to the conventional
2-tuned-circuit coils. Antenna, R.F. and oscillator circuits are permeability tuned,
offering automatic tuning applications that are both accurate and stable. The entire
coil assembly is mounted in the Remote Tuner control head being connected to the
oscillator and R.F. circuits by an R.F. transmission cable.
The R.F. oscillator, and I.F. and A.F. amplifiers, including the power supply,
are contained in the speaker case.
This unit has been designed to facilitate servicing.
RF Cascade Workbook for Excel
RF & Electronics Symbols for Visio
RF & Electronics Symbols for Office
RF & Electronics Stencils for Visio
RF Workbench
T-Shirts, Mugs, Cups, Ball Caps, Mouse Pads
Espresso Engineering Workbook™
Smith Chart™ for Excel
|
|
Belmont Radio Corporation: A Brief Overview and Historical Context |
High Technology Companies
- See Full List of AI Topics -
Belmont Radio was a manufacturing company that produced a range of radio equipment,
including radios, amplifiers, and speakers. The company was known for its innovative
designs and high-quality products, and was a leader in the radio industry during
its time.
Founded in the early 20th century, Belmont Radio began as a small company that
produced simple crystal radio sets. As radio technology advanced, the company expanded
its product line to include more sophisticated radio equipment, such as amplifiers
and speakers. Belmont Radio also developed its own patented radio technologies,
which helped to set it apart from its competitors.
One of the key innovations that Belmont Radio is remembered for is its development
of the "All-Wave" radio, which allowed listeners to receive broadcasts from around
the world. This was a significant advancement in radio technology, as previous radios
were limited to receiving local broadcasts. Belmont Radio's All-Wave radio was widely
popular and helped to establish the company as a leading manufacturer of radio equipment.
In addition to its radio equipment, Belmont Radio was also known for its distinctive,
high-quality speakers. The company's speakers were designed to deliver excellent
sound quality and were popular with both radio enthusiasts and music lovers. Belmont
Radio speakers were used in a variety of settings, including homes, businesses,
and public spaces.
Unfortunately, as the radio industry evolved and new technologies emerged, Belmont
Radio struggled to remain competitive. The company eventually went out of business,
but its legacy lived on through its many innovations and its high-quality products.
Today, Belmont Radio is remembered as a pioneering company that helped to shape
the radio industry and bring the magic of radio to the masses.
This content was generated by the ChatGPT
artificial intelligence (AI) engine. Some review was performed to help detect and
correct any inaccuracies; however, you are encouraged to verify the information
yourself if it will be used for critical applications. In some cases, multiple solicitations
to ChatGPT were used to assimilate final content. Images and external hyperlinks
have also been added occasionally. Courts have ruled that AI-generated content is
not subject to copyright restrictions, but since I modify them, everything here
is protected by RF Cafe copyright. Your use of this data implies an agreement to
hold totally harmless Kirt Blattenberger, RF Cafe, and any and all of its assigns.
Thank you. Here are the major categories.
Electronics & High Tech
Companies | Electronics &
Tech Publications | Electronics &
Tech Pioneers | Electronics &
Tech Principles |
Tech Standards
Groups & Industry Associations |
Societal Influences on Technology
|
|
|
|
|
Posted July 10, 2019
Radio Service Data Sheets
These schematics, tuning instructions, and other data are reproduced from my
collection of vintage radio and electronics magazines. As back in the era, similar
schematic and service info was available for purchase from sources such as
SAMS Photofacts, but these printings
were a no-cost bonus for readers. There are 227 Radio Service Data Sheets as of
December 28, 2020.
-
AMRAD
Model 81 "Bel Canto"
-
GE
Model 250 Radio Service Data Sheet
- Hoffman
Model A300
- Emerson
Model 505
- Olympic
Models 6-501, 6-502, 6-503
- Radiola
Models 61-5, 61-10
- Farnsworth
Models ET-060, ET-061, ET-063
- General
Electric Model 321
-
Garod Model 6AU-1
- Truetone
Model D4620
- Westinghouse
Model H-148
- Wards Models
54BR-1501A, 1502A
- Majestic
Models 8S452, 8S473
- RCA Models
Q22A, Q32
- Zenith Model
5G003ZZ
- Mantola Models
92503 and 92504
- Emerson Model
508 Series 8-7434351 and Up
- Belmont Model
A-5D118
- Wards Model
74BR-2707A
- Crosley Model
56TP-L
- Admiral Model
7C60 Chassis 6B1
- 336
Belmont Radio Model 6D111, Series A
-
333 General Electric Models 100, 101, 103 and 105
- RCA Victor
Models 54B1, 54B-N, 54B2, 54B3 Radio Data Sheet 335
-
National Union "Presentation" Radio Model G-619
-
Zenith Radio Models 8H032, 8H033, 8H050, 8H052, 8H061
-
General Electric Farm Radio Model 280
-
Admiral Model 6RT44-7B1
-
Montgomery Ward Airline Model 04BR-1105A Radio
- Belmont
Model 678 Auto-Radio Set
- Sentinel
Model 217-P Portable Radio Set Radio
- Remler
Model No. 36 Dual-Wave Auto-Radio
-
Stromberg-Carlson No. 82 All-Wave Receiver
-
Majestic A.V.C. Model 290 Chassis
- FADA 9 Tube
Model 190 "Metal" All-Wave
- RCA Victor
Models 9T and K2 9-Tube, 5- to 566-Meter
-
Motorola "Golden Voice" Model
-
RCA Victor Model H-6
-
Simplex Model TA
-
Automatic "Magic Eye" Model A1
- Silvertone
Models 4488 and 4588 (Chassis No.101412) and 4488A and 4588A (Chassis No. 101412A)
- RCA Victor
Model M109 "De Luxe" 7-Tube Auto-Radio Receiver
- Crosley Model
6625 6-Tube 3-Band Receiver
- International
Model 77 Series 7-Tube Dual-Band Receiver
- Belmont
Model 6D121
-
General Electric Models 60, 62
- Admiral
Model 7C64
-
Radiola "28" Super and "104" Power Speaker
- Sonora
Model TW-49
-
Stromberg-Carlson Models 1020, 1120, Series 10
- Air King
Model 4604D
- Sparton Models
526, 526X, 526PS
- Truetone
Model D2624
- Admiral
Models 6EI, 6EIN
- Detrola Models
571A, 571B
-
General Electric Model 250
- Howard Model
920
- Colonial
Model 652 5-Tube Broadcast-Short-Wave
-
Fairbanks-Morse
9-Tube All-Wave Model 91
-
International Model 500 5-Tube Dual-Range Battery
- Emerson Model
678 "Auto-Dynamic" 5 Tube
-
Stromberg-Carlson
Nos. 230 and 231 Series
- Atwater
Kent Model 649 All-Wave
-
Howard Model G-26, and "Airplane 4" Model AA25
-
Montgomery Ward "Airline" Series 7GM 7-Tube High-Fidelity Receiver
- RCA
Victor Model T5-2 5-Tube, 2-Band A.C. Superheterodyne Receiver
-
Majestic
"Models 50," "51" and "52"
-
Bremer-Tully Model 7-70 and 7-71
-
General
Electric Model M-49 4-Tube Radio-Phonograph Dual-Wave Superheterodyne
- RCA-Victor
Radiola "Superette" Model R7 Superheterodyne
- Crosley Model AC-7
and AC-7C
-
Westinghouse
"Columnaire" Models WR-8 and WR-8-R (Remote Control)
-
Characteristics
of Metal Tubes - and Other "Octal" (8-Prong) Base Types
- Kolster K20,
K22, K25, K27 and K37 Six-Tube Receivers
-
Stromberg-Carlson
Nos. 62 and 63, 8-Tube High-Fidelity Chassis
- RCA Model
103, 4-Tube A.C. Compact Dual-Wave
- FADA "Special"
Model 265-A and FADA "7" Model 475-A
-
General Electric Model C-62 6-Tube Battery
- Emerson
5A Automotive
- Zenith
666 Automotive
- Motorola
100 Automotive
-
Crosley
Roamio 4-A-1 Automotive
-
American-Bosch
524A Automotive
- Crosley
Model 1316 (in Model 167 Console)
- RCA Victor
"High-Fidelity Electrola," Model R-99
- AMRAD
Model 81 ("Bel Canto" Series) Receiver
-
Fada 103 Fadalette, Stewart-Warner Series 108, DeWald 54 Dynette Sets
- RCA
Victor R-27 and Philco 53 Ultra-Midget A.C.-D.C. Radio Receivers
-
Majestic Models Fairfax and Sheffield 8-Tube
- Stromberg-Carlson
No. 29, 9-Tube Superhet
-
International Kadette Model 400 4-Tube Battery-Operated Superhet
- RCA Victor
Model 5M 5-Tube Auto Superhet
-
Majestic Model 11 Short-Wave Converter
-
Silver-Marshall
Model 727-DC Battery-Operated Superheterodyne
- RCA
Victor Model VHR-307 Home Recording - Phono-Radio Combination
-
Delco 32-Volt Radio Receiver Chassis Models RA-3, RB-3 and RC-3
- Majestic
Chassis Models 380 A.C. T.R.F., and 400 A.C.-D.C. Superheterodyne
- General
Motors S1A, S1B
- Admiral
Model 7C63, Chassis 7C1
- Westinghouse
Model H-133
- Arvin
Models 150TC, 151TC
- Kadette Model
90 Duplex
-
RCA-Victor "Magic Brain" Model 281
- Grunow
11A Chassis 11-Tube All-Wave Superheterodyne
-
Sears, Roebuck & Co., Silvertone "Rocket" Models 6110 and 6111
-
General Electric Model GD-52
-
Zenith Models 6D302, 6D311, 6D326, 6D336, 6D360
-
Allied Radio, Knight Model E10913
- Arvin Model
140P
- Emerson
Models 501, 502, 504
- Crosley
Model 56TD-W
- Hoffman
Model A500
-
Stewart-Warner
Model 9003-B
-
Zenith Models 6D014, 6D029
- Coronet
Model C-2
- Sparton
Models 7-46, 7-46PA, 8-46, 8-46PA
-
Stewart-Warner Models 9001-C, D, E, F
-
Zenith Models 5D011-5D027
- Bendix Models
636A, C, D
- ECA Model 108
-
International Model 66 and 666, 6-Tube Superhet
-
Ford-Philco
Radio, Model FT9, 6-Tube Auto-Radio Receiver
- Howard
Explorer Model W Deluxe 19 Tube All-Wave Superhet
- RCA Victor
Portable Table Electrola Model R-95
- Atwater
Kent Model 305Z 5-Tube 32 V. D.C. Superhet
- Kadette
Jewel Model 40 Chassis 3-Tube Ultra-Midget Receivers
-
General Electric Model N-60 6-Tube Auto Superheterodyne
-
Sparton Model 40 6-Tube T.R.F. Automotive Receiver
-
Clarion "Replacement" Chassis, Model AC-160 A.V.C. Superheterodyne
- Emerson Models
20A and 25A
- General
Electric K-40A
- Pilot Model
B-2
- RCA-Victor
Radiola Model M-30 Automotive Radio
- Motovox
Models 10A All-Electric and 10E Battery-Operated "Moto-Tetradynes"
-
Kennedy Superheterodyne Short-Wave Converter
- RCA
Victor Model R-78 B1-Acoustic 12-Tube
- Philco
Model 15 Series, 11-Tube Superheterodyne Chassis
-
Zenith Challenger Model 740
-
Sparton
Selectronne Receivers Models 1068 and 1068X
- Fada Model
155 Super Fadalette A.C.-D.C. Set
-
Clarion De Luxe Models AC-280 and 25-280
-
Crosley Model A-157 (River Roamio) Auto Radio
- Philco Model
'37-116 Codes 121 (Shadometer) and 122 (Dial Tuning)
-
Arvin Model 28
-
Philco Model 818
-
Fada Model 266 Motoset
-
Bosch Models 736, 737, 738
- RCA-Victor
Model 15U, Radio-Phonograph
- Sparton
Models 566 ("Bluebird" Mirror), A.C.-D.C. 5-Tube 2-Band Midget Superhet
- Atwater
Kent Model 776 6-Tube Auto Radio
- Stromberg-Carlson
No. 61 4-Band 7-Tube A.C.-D.C. Receiver
- Arvin Model
182TFM
- Crosley
Model 58TK
- Westinghouse
Model H-165
-
General Electric Models G-105 and G-106
- Silvertone
"F," "FF," "G," "H," and "J"
-
Stewart-Warner Model 03-5A1 to 03-5A9 (Chassis 03-5A) Senior Varsity Radio
- Radiola Models
61-6, 61-7
-
Westinghouse
Models H-104, H-105, H-107, H-108
- Farnsworth
Models EC-260, EK-262, EK-263, EK-264, EK-265
-
United
Models 980744, 980745
-
Stewart-Warner (R-127 Chassis) Models 1271 to 1279 All-Wave
- ERLA Model
4500 Dual-Wave T.R.F. 4-Tube A.C. Receiver
- Clarion No. TC-31
5-Tube A.C.-D.C. Superhet.
- Detrola Model
105C 5-Tube Dual-Band A.C.-D.C.
- Zenith
6-Tube All-Wave Chassis No. 5634
- RCA Victor
Model 261, 555 to 107 Meter
- Philco
Model 38-116; Code 125
-
Stewart-Warner "Ferrodyne" Chassis Model R-136
-
American-Bosch
Model 43OT 5-Tube 3-Band Superheterodyne
- RCA
Victor Model C9-4 9-Tube 3-Band Superheterodyne
- Kennedy "Model
826B" Combination Receiver
- Steinite
50-A and 102-A
- Pilot Model
63 All-Wave 6-Tube Superheterodyne
- Stromberg-Carlson
No. 69 4-Tube All-Wave Superhet. Selector (Converter)
- RCA
Victor Model 102 4-Tube A.C.-D.C. T.R.F. Receiver
- Bosch Models 60
and 61
-
Atwater Kent Models 30, 33, 35, 48 and 49
- Crosley Model
120 Senior Superheterodyne (Pliodynatron) Chassis
-
Columbia Screen-Grid 8 Receiver
-
General Electric Models A82 and A87, 8-Metal-Tube All-Wave A.C. Superhet.
- Colonial
31 and 32 D.C.
- Zenith 5-Tube
Triple-Wave Chassis nos. 5508 and 5509
- Remler Model
46 ("Scottie")
- General
Electric FA-60 and FA-61
-
Stewart-Warner
Series 900
-
Howard
Model B-5 (715), Series 1 and 2 (Sheaffer Radio-Clock-Pen Desk Set)
-
Ford-Philco Car-Radio Models F-1440 and F-1442
-
Brunswick Model 31 Combination Radio and Panatrope
- Emerson Models
38, 42 and 49, 6-Tube Dual-Wave (Chassis U6)
-
General Motors Chevrolet No. 601574 Automotive
-
RCA Victor M-104 (and M-108) Automotive
- Arvin-Ford
17-A Automotive
-
Westinghouse Model WR 207 & WR 208 5-Tube Dual-Band Superheterodyne
- Radiolas
"Super VIII" (AR-810, "Semi-Portable" (AR-812), 24 and 26
- Howard Model
45 A. V. C.
- Majestic
Model 25
-
Galvin Motorola Model 61
-
Arvin Model 6
- Admiral
Models 7T06, 7T12
- Garod Model 5A1
- Hoffman Model A301
-
Knight Model E10716 Battery Portable
- Arvin Models 555,
555A, 552N, 552AN
- Grantline Models
605, 606
- Truetone Model
D2616
- Belmont Model
5D128
- Arvin Models 444,
444A
-
International Kadette Model 1019
-
Stewart-Warner Models 97-561 to 97-569
- General
Electric Model 280
- Zenith Models 5R080,
5R086
- Truetone Models
D1747, D1748
-
Crosley Roamio Automotive T.R.F. Models 90, 91, 92
-
Crosley Roamio Automotive Superheterodyne Models 95, 96
-
Wells-Gardner Series 062
-
Emerson
Model AZ-196
- Belmont Model
5P19
- Crosley
Fortyfive
- Crosley Model
56FC
-
Emerson
Models 507, 509, 518, 522, 535
- Garod Model 6AU-1
- General
Electric Models 219, 202, 221
-
Crosley "Chairside" Model 567
-
Belmont Model 408 Battery "Farm"
- Wards Model
74BR-1055A
- Farnsworth
Models EK-081, EK-082, EK-083, EK-681
- Philco
Model 200-X Radio
-
Admiral "Aeroscope" Models 161-5L, 162-5L and 163-5L
- Philco
Model 59, 4-Tube A.C. Midget Superheterodyne
- Zenith
Farm Model 6V 27, 6-Tube Superhet
- Ward 10-Tube
All-Wave High-Fidelity Superhet, Series ODM
-
Philco-Packard
Deluxe
-
Canadian
Westinghouse Model 175
- Crosley Model
1155
- Philco Models
39 and 39A
-
Arvin Model 35 8-Tube Car-Radio
- Hetro
Air-Ace Series M
- Westinghouse
Models H-161, H-168, H-168A
- Garod Model 5A4
- Arvin Models 152T,
153T
- Belmont Model 5240
- Mantola Models 92505,
92506
- General Electric
Models 102, 102W, 107, 107W, 114, 114W, 115, 115W
- Crosley Model
555 (A.F.M.)
- Crosley Model
515 (Fiver)
- Crosley Model
425 (Travo)
-
Firestone-Stewart-Warner Model R1332
- Fairbanks-Morse
Model 81 "Farm" Set
- Clarion Model
423, 470, 471, 472, 480
-
International Radio Corp. Model 90
- Belmont Model
578 Series A
|