Diagrams of the Newest Car-Radio Receivers
June 1936 Radio-Craft

June 1936 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.

These 8 new schematics from a 1936 issue of Radio-Craft magazine for vintage tube-type car radios brings the total to 210 posted on RF Cafe. Included are Motorola "Golden Voice" Model, RCA Victor Model H-6, Simplex Model TA, Automatic "Magic Eye" Model A1, Arvin Model 28, Philco Model 818, Fada Model 266 Motoset, Bosch Models 736, 737, 738. The Motorla "golden Voice" model features a "magic eliminode" circuit which not only filters out automobile engine noise, but balances the noise out of the antenna lead, so that suppressorless operation is possible on almost all cars. A glance at the schematic shows that all that magic is performed by a built-in L-C filter network for the power supply, and an antenna tuning circuit. In those days, installation of a radio in a car usually required the skills of an electronics technician in order to match the antenna and fine-tune the receiver according to its environment.

Diagrams of the Newest Car-Radio Receivers 

The friend of design of the new receivers can most readily by an examination of the actual circuits.

(1) Automatic "Magic Eye" Model A1. A novelty of this set is its "magic eye" 6E5 tuning tube. The set may be had with or without this feature. Operation is possible in most cases with only a generator condenser and a distributor suppressor. The set is mounted directly below the dash, and no remote control is used. Alignment of the set is done at 1,400 kc. Installation is made with 2 screws fastened to the dash and a single heavy bolt at the rear, through the motor compartment bulkhead. For installation in the Willys 77, a roof antenna of about 10 square ft. of copper screen should be used. Voltages: Plate - V1, V2, 220; V3, 120; V4, 200. S.-G. - V1, V2, 95; V4, 220. Cath. - V1, 3; V2, 3.7; V3, 1.3. Bias of V4, 14 V., drop across the "B" choke. (Photo on page. 712)

(2) Bosch Models 736, 737, 738. These sets are the same except for the speaker equipment. The model 736 uses a self-contained speaker, model, 737 is used with a header-type speaker, and 738 has a separately mounted dash speaker. Various makes of cars will require different treatment for noise suppression, but complete instructions are furnished with the set. The tubes used in this set are quick-heater types. The tone control knob is located on the side of the receiver case. The antenna cable is cut to a specific length and should not be shortened. Any excess may be coiled up out of the way. An antenna loading is included in this cable. This set may be used with any type of car antenna. The new grid-bias cell is used in this receiver and under normal use will not need replacement during the life of the car. The 0Z4 rectifier tube is similar in action to the old BH rectifiers, but is much improved. Voltages to be found in this set will vary rather widely according to the condition of the battery and vibrator, but the normal high voltage is around 240 V. A 20 A. fuse is used forprotection of battery. (Photo on page 712)

(3) Simplex Model TA. This is one of comparatively few using the synchronous type of vibrator, which eliminates the necessity for a rectifier tube. If the car battery is grounded on the negative side, the vibrator must he removed from its socket and tuned half-way around before inserting. It is normally shipped for use with the ground on the positive side. An antenna trimmer is used to adjust the set to the most accurate balance with the, particular antenna used. The trimmer is located at the bottom of the cabinet under a small plug. It should be adjusted with. the set in the car, and connected to the car antenna. Ordinarily, only a distributor suppressor is necessary with this car, the battery input being well filtered.

(4) Fada Model 266 Motoset. This set may be used with a self-contained speaker, a roof or other outside speaker, or it may be used with dual speakers. The plug connections of the different types are shown at the bottom of the diagram at right. The input "A" leads are very completely filtered, to keep out ignition noise. The antenna input transformer is of the iron-core type, and this unit raises the sensitivity of the set to a considerable degree. Two of the new metal tubes are used, including the 6Q7 double-diode triode, which is closely equivalent to the 75. Voltages at tube prongs are: Plate - V1, 162; V2, 160; V3, 162; V4, 107; V5, 226. S.-G. - V1, 68; V2, 66; V5, 236. Plate current: V1, 3; V2, 3.4; V3, 2.9; V4, 0.3; V5, 19; V6, (total) 37. These readings were taken with a 1,000 ohm-per-volt meter and are not indicative of effective voltages. The readings were taken with a supply voltage, of 6.0, and the current was 5.6 A. The I.F. transformers are to be aligned at 175 kc., while the gang trimmers are set at a reading of 1,500 kc. The oscillator aeries trimmer must be aligned at a frequency of 600 kc. The "hot A" lead has a fused connector for protection. (This is the circuit of the receiver shown at upper right, page 713.)

(5) Philco Model 818. When this set is used in a car having a lop antenna, under-car antenna, spare-wheel antenna, or any other having low relative capacity (50 mmf. to 450 mmf.), use connector plug in "A." For antennas of high relative capacity, such as metal insert top antenna, insulated door, insulated trunk cover (450 to 2,500 mmr.), use condenser plug in "B." Adjustment frequencies are: 1,550 kc. and 580 kc., for R.F. and detector. The antenna adjustment should preferably be made with the set in the car and attached to the car antenna. Iron-core I.F. transformers are used and add greatly to the sensitivity of the receiver. All leads out of the receiver case are very completely filtered. Continuously variable tone compensation is available. The input lead from battery is fused. The manufacturers prefer not to give complete voltage data, since voltages vary widely with different conditions, but with a fully-charged battery, the high voltage is about 180 to 220 V. (Photo on page 712.)

6) RCA Victor Model H-6. A special antenna circuit is used which contains a band-pass filter, affecting a sharp reduction of frequencies out of the band of 540 to 1,660 kc. "Hot" spots of ignition interference on the chassis have been carefully located and grounded. A single-position tone control is used. There is a total of 7 tuned circuits in the R.F. section of the set. The reproducer is a separate unit. Alignment frequencies are: 1,400 kc. for ant. and det. coils, and 600 and 1,400 kc. for osc. coil. Undistorted output is 1.75 W. and maximum is 3.5 W. Battery current drain is 6.55 A. A control panel mounts directly in the dash of the car. Set size is 6 1/8 x 9 5/8 x 6 1/2 ins. high. Voltages : Plate - V1, 205; V2†, 205; V3, 205; V4, 90*; V5, 235. S.-G. - V1, 82; V2, 82; V3, 82; V4, 20*; V5, 245. Cath. - V1, 2.5; V2, 2.5; V3, 3; V4, 0; V5, 20. *Cannot be meas. with ordinary meter. †V2, osc. plate, 205.

(7) Motorola "Golden Voice" Model. This set contains the "magic eliminode" circuit. which not only filters out motor noise, but balances the noise out of the antenna lead, so that suppressorless operation is possible on almost all cars. This unit also incorporates an antenna tuning circuit to properly match and tune the set to any type of antenna. Besides the tone control and the normal volume control, this set has a variable sensitivity control, which is mounted on the front of the case. The input tuning coil of the R.F. stage is of the iron-core type. The output stage is of the class AB type, with a separate bias rectifier system, using a 6H6 with an independent filter. The bias from this source is used on both A.F. stages. The circuit herewith published is the latest and supersedes all others. Delayed A. V.C. is employed and is affected by the use of V4 in conjunction with V5. Do not connect any condenser from the hot "A" lead to ground as this would nullify the action of the eliminode. All necessary filtering is contained in the latter. Current drain from a fresh battery is 8A., producing 250 V. (Photo on page 712.)

(8) Arvin Model 28. This set may be had with either enclosed or separate speaker. Also matching dash control panels may be had, or the set may be equipped with a streamline steering-column control. A complete noise filter is built-in. Special iron-core antenna tuning system consists of two couplers assuring high gain on the smallest antenna. Full A.V.C. holds signal steady, while continuously-variable tone control covers complete tonal range. The set must be balanced at 1,400 kc., and checked for accuracy at 1,000 and 600 kc. Tubular fixed condensers are firmly fastened to chassis, eliminating broken leads. Copper plated chassis and case with locking snap-on covers add to stability and ease of servicing. Only one hole to drill to install chassis in any position, back or side. Tuning condenser is rubber mounted and has an improved high-ratio vernier drive, enabling the greatest possible ease of tuning. Voltages: Plate - V1, V2, V3, 235; V4, 120; V5, 230. S.-G. - V1, V2, V3, 90; V5, 235. Cath. - V1, V2, 4; V3, 2.3; V4, 1.6; V5, 16. Osc. plate, V2, 160.

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

Posted January 17, 2024
(updated from original post on 8/3/2017)