Crosley Roamio Automotive Superheterodyne Models 95 and 96
Radio Service Data Sheet
April 1933 Radio-Craft

April 1933 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.

Crosley Roamio Automotive Superheterodyne Models 95 and 96 Radio Service Data Sheet

The superheterodyne series of Crosley Roamio sets; Radio Service Data Sheet No. 87 describes the T.R.F. series.)

Model 95

Average operating potentials are given in the following tabulation. These figures are measured with the speaker connected; a high-resistance meter will be required to obtain correct readings.

*A. V. C. only.

The pole of the "A" battery which is not directly connected to the frame of the car connects through the insulated battery cable lead to the cable connector of the receiver, and thence to one pole of the power switch; this D. P. D. T. unit controls both the "A" and "B" circuits. After going through the switch, the "A" circuit branches, one branch going to the heaters (connected in parallel) and through them to the chassis, another going through the dial light to the chassis, and the third going through the speaker field, to the speaker cable shield, and then through the battery cable shield to the other side of the "A" battery which connects to the frame of the car.

Tube V1 incorporates the dual action of oscillator and first-detector. Tube V4 is connected as a diode and serves the dual functions of automatic volume control and A.V.C.

The grid of the output pentode, V6, is connected to the chassis through a grid leak of 0.3-meg. (in models using a type 38 pentode this resistor has a value of 0.5-meg.). The output volume is determined by the setting of the 3-meg, potentiometer, R1.

The A.V.C. potential is developed across resistors R2, R3, which connect to the plate of the second-detector, V4. The maximum negative potential (the total drop across R2, R3) is applied to the control-grid of the pentode I.F. amplifier, V2, through filter resistor R4. A lower potential is obtained at the center-tap of resistors R2, R3, and this voltage is applied to the control-grid of the screen-grid I.F. amplifier, V3, through filter resistor R5. Thus, resistors R2, R3 serve the dual functions of supplying A.V.C. potential, and at the same time acting as the load resistor combination across which is developed the A.F. potential which is applied to the .03-mf. coupling condenser and thence to the combination grid-leak and manual volume control potentiometer R1.

The two 8 mf. condensers are electrolytic units and are contained in one can.

To re-align the set, turn the station selector to 550 kc., and adjust the service oscillator to 181.5 kc., after first connecting it, through a condenser of 0.1-mf., to the control-grid of V1. Ground the other side of the service oscillator, and do not remove the control-grid clip-wire (of the set) from V1. Next, adjust the I.F. trimming condensers of I.F.T.1 for maximum reading, and then adjust the trimmers in shunt to the secondaries of I.F.T.2 and I.F.T.3, respectively, for maximum output-meter reading.

After this step has been completed, the antenna and oscillator circuits, respectively, may be aligned.

Police Roamio model 951 is the same as the model 95, except for the coils which are designed for the police band.

Model 96

Following are the average operating potentials to be measured with a high-resistance meter.

The aligning procedure in connection with this receiver is the same as for the Model 95 chassis, except that the high side of the service oscillator connects through a condenser of 0.1-mf., not to the first tube in the set, V1, but to the first-detector, V2, for making the I.F. adjustments. After setting the station-selector dial to 550 kc., adjust the service oscillator to 181.5 kc., and proceed as previously described.

Then, tune the service oscillator to 1,400 kc., set the station-selector dial to 1,400 kc., and connect the high side of the service oscillator, through a condenser of 250 mmf. to the antenna lead of the receiver; the low side of the service oscillator connects to the chassis.

It is preferable to use a dummy antenna in making these adjustments. Align the I.F. and R.F. circuits for maximum reading on the output meter. The circuits of L1, L2 and L3 should not be adjusted until the I.F. circuits have been aligned.

The action of the A.V.C. section of this receiver model is a bit more complicated than that of the previously-described Roamio A.V.C. circuits. Consequently, the interested Service Man is referred to the September, 1932 issue of Radio-Craft, which contains a lengthy description of the diode-triode tube, in the article; "Still More New Tubes"; fundamental data regarding A.V.C. circuits in general are discussed at considerable length in the article, "Operation and Service of Automatic Volume Control Systems" (in the same issue).

The manual volume control resistor, R1, has a value of 3 megs.

Variation in tube current supplied by the automobile storage battery, due to fluctuations caused by the generator and load on the battery, is a cause of so-called "interference" in many automobile receivers. Although these Roamio models are designed to eliminate this effect as much as possible, in order to insure the best reception it may be advisable to pay particular attention to the connection of the yellow "A" lead, running it direct to the car battery rather than to other possible locations to the "A" supply.

Whether filter condensers will be required in shunt to the electric horn, electric windshield wiper, electric fan, etc., may be determined by shunting these units with a, test condenser of about 2 mf.

Posted December 26, 2019
(updated from original post on 12/28/2015)

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