Howard Explorer Model W Deluxe 19 Tube All-Wave Superhet
Radio Service Data Sheet
September 1934 Radio-Craft

September 1934 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.

Here are the schematics, chassis layout, and service info for the Howard Explorer Model W Deluxe 19 Tube All-Wave Superheterodyne console style (sits on the floor) radio. The wooden cabinet format is somewhat unusual in that the top is a flat surface rather than the having more typical curvaceous lines that radios of the era sported. It looks a lot like the models with built-in phonographs, where the top would tilt upward. The Radio Service Data Sheets that were published in Radio-Craft usually seem to have more information included than those published in other magazines, at least in the same era (1940-ish). It might have to do with how much material is provided by the manufacturer rather than a decision by the magazine editors. This one appeared in the September 1934 issue. Believe it or not, there are still people searching for such data. I could not find an example of a real surviving Howard Explorer Model W Deluxe radio.

Howard Explorer Model W Deluxe 19 Tube All-Wave Superhet Radio Service Data Sheet

(Uses single-purpose tubes to secure extreme circuit stability: wavelength range, 13.6 to 2,142 meters; provides for either inverted-L doublet antenna; neon resonance indicator; zero-beat oscillator; variable Q A.V.C.; tone control; variable A.V.C. parallel push-pull output 245s.)

A 19 tube radio receiver in its home. Airplane-type dials are used; only the tuning dial sector of the band in use is illuminated. as the band switch is turned.

Schematic circuit of the A.F. amplifier and power pack chassis. There are 9 tubes in this section of the instrument. A "theatre" type dynamic speaker is used,

Until very recently the general practice has been to utilize the new tubes at their maximum capabilities. Consequently, a slight change in characteristics would greatly affect the operation of the complete receiver. However, this 19 tube set is designed to utilize its tube complement very conservatively, with the result that great stability has been achieved which, after all, is a major factor in securing satisfactory reception, especially on the short waves.

Note; it is inadvisable to attempt to realign the set except as a last resort. The recommended procedure, only to be used by expert radio Service Men, is as follows:

To align the I.F. circuits feed the I.F. service oscillator test signal into the control-grid of V2.

When aligning R.F., I.F., or oscillator circuits turn A.V.C. adjustment (slotted shaft) to extreme left. The I.F. trimmers are very critical, greatly affect the performance of the set, and must be carefully resonated.

Aligning R.F. and Oscillator Circuits

Adjust A.V.C. control to extreme left position. It is unnecessary to remove the set oscillator tube. Align the circuits only in the sequence given.

To align the set oscillator turn its trimmer all the way out and then select the strongest signal when turning it in; set insensitivity near the center of the dial will result if the wrong oscillator signal is used.

Bend the variable condenser plates for kc. dial alignment only in the broadcast band. Before adjusting any band, make certain that the pointer of the station indicator is set on the last black line when the dial is turned all the way to the left on the broadcast band just above 0.55 (Maximum capacity of the variable condenser).

Long-Wave Band

Turn the band indicator to 0.15-0.35, set the dial to 0.35, and feed 350 kc. into the antenna post. Resonate the trimmer (not green coded on the trimmer washer) in the long-wave oscillator can. Align the R.F. and antenna stages. Reset dial to just above 0.17 and resonate the green coded oscillator trimmer at 175 kc. Recheck the 350 kc. setting.

Broadcast Band

It is necessary on the broadcast band only, that a metal plate with holes in line with the trimmer nuts be used so that the circuits are not detuned when the regular base plate is screwed back on.

Turn the band indicator to broadcast 0.55 to 1.5, set the dial to 1.4, and feed in 1,400 kc. Resonate trimmer 14, R.F. trimmer 7 and the antenna trimmer (knurled knob extending from top of antenna coil can). Now rotate dial to 0.55 and resonate trimmer 10 at 550 kc. Re-check the setting at 1,400 and bend plates of variable condenser at 950 and other points where necessary to secure kc. reading on dial.

Short-Wave Band No.1

Turn band indicator to 1.5 to 3.5, set dial to 3.5, and feed in 3,500 kc. service oscillator signal. Resonate trimmer 13, R.F. trimmer 6 and antenna trimmer 3. Rotate dial to 0.55 on broadcast hand. (The short-wave dial calibration may be inaccurate at this point and the 0.55 figure corresponds to 1.5 on short-wave band No. 1.) Feed in 1,500 kc. and resonate trimmer 9. Recheck at 3,500 kc.

Short-Wave Band No.2

Turn band indicator to 3.5 to 9, set dial to about 8.9 (due to off-calibration this corresponds to 8.5), and feed in 8,500 kc. Resonate trimmer 12, R.F. trimmer 5 and antenna trimmer 2. Rotate dial to 3.5 and resonate trimmer 8 at 3,500 kc. Recheck at 8.5 (8.9).

Short-Wave Band No.3

Turn band indicator to 9 to 21, set dial to 20, and feed in 20,000 kc. Resonate oscillator trimmer 11, R.F. trimmer 4 and antenna trimmer 1. The alignment at 9 is obtained by use of the fixed condensers which should not require change. To insure band sensitivity in the region of major foreign program reception, turn the dial to 12 and resonate antenna coil trimmer 1 at 12,000 kc.

Note that since all adjustments are made with the A.V.C. inactive, extreme care must be used to attenuate the input signal low enough so that there will be no overloading of tube amplifiers while making adjustments.

After these high-frequency adjustments have been made, the service oscillator setting should be advanced 930 kc. and the output signal strength considerably increased; non-reception of the image signal indicates incorrect set oscillator adjustment. For example: a service oscillator signal of 20,930 kc. should be perceptible at 20 on the dial after alignment to 20,000 kc.

Beat Oscillator Adjustments

Turn the main dial to receive a service oscillator signal of 4,800 kc., and make sure that the band on the "beat oscillator" (Frequency Meter V17) falls on 1.5 when the 2 gang condenser is at full capacity.

Turn Osc. Sw. to the right ("Mod."), and frequency dial to 4. Resonate the trimmer on the 2 gang condenser to main dial setting. Turn band indicator switch to short-wave band No. 1 (1.5 to 3.5), set main dial to where 1,500 kc. comes in, turn frequency dial to 1.5, and then resonate trimmer 15.

A.V.C. Adjustment

Connect one side of a high-resistance voltmeter to A. V.C. potentiometer terminal which connects to the "high" side of the 0.2-meg. resistor and to the 0.1·mf. fixed condenser, and the other (positive) to chassis ground.

Adjust the receiver for reception of a signal intensity of 3,000 to 4,000 micro-volts, and vary for maximum voltmeter reading, in a given locality, the adjustment in the top, next to the neon adjustment, of the coil can assembly in the upper right-hand corner (facing rear of tuner).

In certain localities close to a broadcast station it may be necessary to readjust the A. V.C. (slotted shaft) control. Exactly resonate the receiver. Then, if the station's signals sound "fringy" or rough, turn the control to the right only sufficiently far to correct this condition.

Neon Tuning Indicator and Q.A.V.C.

Facing the back of the tuner chassis, extending through one of the tall shielded assemblies in the upper right-hand corner, will be found a small, black knurled knob used to adjust the neon resonance indicator. It is advantageous to be able to set this adjustment if excessive fading is experienced due to locality. Adjust the receiver dial to a powerful station during the time of day in which it is received strongest. Then turn the neon adjustment until the light just fills the opening in arrow dial. Readjust the tuning dial of the receiver; should the light become more brilliant, leave the dial at the point of highest brilliancy and again readjust the neon indicator until it just fills the arrow opening. (This adjustment need be made only when the set is installed.)

Since the interstation noise suppression system or Q.A.V.C. is a proportional function of the neon light, the Q.A.V.C. system will be correctly adjusted.

Note that the neon light system is not intended to work on the short-wave stations. However, it will usually indicate resonance to more powerful signals.

Resistor X is an oscillator suppressor in short-wave band No.3. Its value is determined by individual requirements.  

Locations of trimmer condensers in the new 19 tube all-wave superheterodyne. This illustration furnishes the necessary information to complete the data In the text.

Schematic circuit of the tuner chassis. There are 10 tubes in this unit. The 2·gang condenser mentioned in the text is located at the right of oscillator V17.

Posted March 27, 2023
(updated from original post on 10/6/2015)

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