RCA Radiola 66

Introduction

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The RCA Radiola 66 Super-Heterodyne is an AC-powered, antenna-type radio receiver utilizing "AC" Radiotrons introduced by the Radio Corporation of America. The receiver, power unit, and RCA electro-dynamic loudspeaker are housed in a console cabinet. Facilities are provided for attaching electric pickup equipment for phonograph record reproduction.

Six "AC" Radiotrons UY-227 and one Radiotron UX-245 are used. The UX-245 is a power-amplifier Radiotron, newly developed by RCA, capable of providing greatly increased volume without distortion. The super-heterodyne circuit includes a tuned antenna coupling circuit, one stage of tuned radio frequency amplification, oscillator, first detector, two stages of intermediate frequency amplification, second (power) detector, and one stage of audio frequency power amplification. A Radiotron UX-280 is used in the power unit to rectify the AC input for the plate and grid supply of all Radiotrons and for the loudspeaker field supply.

This Radiola features an illuminated dial where a magnified image of the rotating scale is projected onto a fixed translucent screen. The dial illumination also indicates whether the power is on or off.

The receiver offers excellent sensitivity and selectivity over the broadcast range of 550 to 1500 kilocycles (545 to 200 meters). The built-in RCA electro-dynamic loudspeaker provides excellent reproduction quality at both low and full volume.

Part I—Installation and Operation

Equipment

One complete set of Radiotrons as follows:

• Six RCA Radiotrons UY-227
• One RCA Radiotron UX-245
• One RCA Radiotron UX-280

Two Mazda No. 41 pilot lamps (one spare); T-3 bulb, miniature base, concentrated filament, 2.5 volts, 0.45 ampere (packed in instruction book envelope).

Antenna and ground equipment (see Part II).

Diagram: Rear View of RCA Radiola 66 with Cover Removed

A diagram shows the internal components of the RCA Radiola 66 with its cover removed. Key labeled parts include: 'Radiotron UX-280' (in the power unit), 'Power Unit', 'Rating Plate', 'Pilot Lamp', 'Spare Pilot Lamp', 'Ant' (Antenna binding post), 'Gnd' (Ground binding post), 'Receiver Unit', and 'Loudspeaker Unit'. Six 'Radiotrons UY-227' are arranged in a row within the receiver unit, and one 'Radiotron UX-245' is also visible.

Installation

Preliminary: After removing the RCA Radiola 66 from its shipping container, take off the rear cover. Unwrap the power cord and bring it out through the large hole in the bottom of the cabinet.

Remove the red bolts and wood blocks used for shipment to clamp the receiver unit. These parts can be saved for future use.

Locate the Radiola near an electrical outlet, preferably where the antenna lead-in and ground connections will be as short as practicable.

Antenna and Ground: Satisfactory reception depends on proper installation. A small hole in the cabinet bottom is provided for antenna and ground leads, which should be insulated wire (No. 14 gauge or larger). Connect the antenna lead to the "ANT" binding post and the ground wire to the "GND" binding post.

Loudspeaker: Ensure all connections are secure at the loudspeaker terminals.

Radiotrons: Handle Radiotrons carefully. Insert them into the proper sockets as shown in Figure 2. Ensure the UX-245 and UX-280 Radiotrons are oriented so their two large pins enter the large holes, and that the base of every Radiotron rests squarely against its socket. Important: Never apply power to the RCA Radiola 66 unless all Radiotrons are in their sockets.

Power Supply: Connect only to AC circuits within the rated voltage and frequency (cycles) specified on the power unit's rating plate. Failure to observe these requirements may damage the Radiola. Consult the Electric Light and Power Company if unsure about the house lighting circuit rating. Do not use a tube protector or line voltage reducer with this Radiola.

Diagram: Pilot Lamp Mounting

A diagram illustrates the pilot lamp mounting mechanism. It shows a socket clamp that slides over a fixed bracket.

Insert the attachment plug of the power cord into an electrical outlet. Set the Power Switch to the "on" position (upward). After allowing approximately 30 seconds for the UY-227 Radiotrons to heat, verify that all Radiotrons are lighted. If not, refer to "Power Supply", Part III. Snap the Power Switch "off".

Pilot Lamp Installation: Turn the Selector counter-clockwise to the extreme position to access the pilot lamp mounting. Remove the socket clamp from the fixed bracket and screw one of the pilot lamps firmly into the socket. Replace the socket clamp on its bracket. Insert the extra bulb into the spare pilot lamp socket.

Set the Power Switch to the "on" position. With the Selector still in the extreme counter-clockwise position, adjust the socket clamp on the fixed bracket until the zero mark of the projected scale on the dial screen is approximately 1/8 inch below the index pointer. Then switch off the power and replace the rear cover.

Diagram: Panel and Controls

A diagram identifies the controls on the front panel: 'Power Switch', 'Volume Control', 'Dial Screen', 'Selector', and 'Local-Distant Switch'.

Operation

1. Set the Power Switch to the "on" position (upward). The pilot lamp should light. Allow approximately 30 seconds for Radiotrons UY-227 to heat before satisfactory reception is possible.
2. Set the Local-Distant Switch to the "DISTANT" position.
3. Set the Volume Control to approximately the middle position. Then turn the Selector slowly in either direction. If no station is heard, advance the Volume Control clockwise slowly while rotating the Selector until a station is heard.
4. Adjust the Selector for maximum signal strength.
5. Adjust to the desired volume using the Volume Control. Due to the Radiola 66's sensitivity, a more satisfactory adjustment may be obtained by setting the Local-Distant Switch to the "LOCAL" position, especially for nearby stations.
6. When finished operating, snap the Power Switch to the "off" position.

Note: If the Volume Control is too far advanced when receiving strong signals, the station may tune in over a broad range. In such cases, turn the Volume Control counter-clockwise until the station is received at only one point on the dial. Best reception is generally obtained with the Volume Control set at the lowest position at which the station can be heard. After setting the Selector correctly, the volume can be increased as desired with the Volume Control.

Part II—General Information

"AC" Line Voltage

The 105-125 volt models (50-60 and 25-40 cycles) are connected for normal operation above 115 volts. The 200-250 volt, 50-60 cycle model is for voltages above 225. The original connection should not be changed unless determined by consulting the RCA Authorized Dealer or Electric Light & Power Company that the supply voltage is normally below this value. Provision exists for adapting the Radiola to voltages below 115 (or 225) via a simple wiring change, which should be performed by an RCA Authorized Dealer.

Tube Protectors

The power transformer is designed to supply correct voltages without a tube protector or line voltage reducer. Using such a device in series with the power supply will reduce the voltage, preventing Radiotrons from operating at highest efficiency. It is recommended that no line voltage reducing device be used.

Power Supply

Reception may possibly be improved by reversing the attachment plug at the electrical outlet.

Radiotrons

The characteristics of circuits connected with sockets No. 1 and 6 are important for operation. It is advisable, when installing, to interchange the UY-227 Radiotrons in sockets No. 1 and 6 with others until best reception is obtained. This arrangement should not be changed afterward. Always switch off the power before interchanging Radiotrons.

Volume

Reduction of volume should be accomplished by adjustment of the Volume Control rather than the Selector Dial.

Selector Dial

The dial scale is arbitrarily graduated from "0" to "100". Approximate kilocycle values are indicated to the left of the scale. Dial settings can be recorded on the Station Log.

Antenna

(a) Outdoor Type: A single-wire antenna (No. 14 bare copper recommended), 25 to 50 feet long, usually provides good reception. A shorter antenna is preferable near high-power broadcast stations; a longer one may improve results in distant localities. The antenna should be isolated from other objects, erected as high as possible, and at right angles to electric light and power lines, without crossing them. The antenna and lead-in should be supported by high-grade glass or glazed porcelain insulators, with the lead-in spaced a foot or more from the building. All connections should be soldered. The lead-in and ground connections should be separated and direct. It is preferable that the lead-in wire be a continuation of the antenna. Where it passes through a wall or window frame, it should be insulated by a porcelain tube. An outdoor antenna should be protected by an approved lightning arrester, per National Board of Fire Underwriters requirements.

(b) Indoor Type: An indoor antenna is less effective for distant reception. If an outdoor antenna is not practicable, satisfactory results may be obtained using about 20 to 40 feet of insulated wire inside the building. No. 18 bell wire is suggested. In buildings with metal lath, results may vary, and different arrangements might be needed.

Ground

A good ground connection is as important as a well-constructed antenna. Instructions vary by location. Water pipes or steam pipes generally make good grounds; avoid gas pipes. The ground lead should connect via an approved ground clamp to a scraped pipe section. If pipes are unavailable, a rod may be driven into the ground. Success depends on soil moisture.

Record Reproduction

For using the Radiola 66 with a phonograph for electric record reproduction, consult the RCA Authorized Dealer.

Part III—Maintenance

Radiotrons

Before inserting or removing Radiotrons, ensure the Power Switch is in the "off" position. Inspect and keep the contact pins clean. It is advisable to have at least one new RCA Radiotron of each type available. Periodically check the condition of each Radiotron by substituting a new one and comparing reception results.

Power Supply

If the pilot lamp and Radiotrons fail to light with the Power Switch "on", check that the attachment plug is properly inserted and the current is not switched off. The Radiola may not be properly connected to the power supply.

Volume Control

If the Volume Control produces a grating sound, turn the knob back and forth between extreme positions a few times to clear any foreign material on the control resistance.

Antenna and Ground

A decrease in receiving range and volume may be caused by loose or corroded connections in the antenna and ground circuit, or by dirt or soot accumulation on antenna insulators.

Diagram: Cabinet Wiring of RCA Radiola 66

A diagram shows the cabinet wiring, illustrating connections for the 'Local-Distant Switch', 'Loudspeaker Unit', 'Power Unit', 'Power Switch', 'Power Cord', and 'Receiver Unit'. It details connections to binding posts ('ANT', 'GND') and the attachment plug, along with wire colors and connections to individual Radiotrons (UY-227, UX-245).

Important

The RCA 90-day guarantee is not effective unless the RCA Guarantee Tag is countersigned and dated at sale by the RCA Authorized Dealer. If the signed tag was not received, ensure the dealer provides it.

Notice

The apparatus and devices, or their use, are covered by patents sold under specific licenses. A notice attached to the apparatus, or on tags/wrappers, details these licenses. The notice states:

"In connection with devices it sells, Radio Corporation of America has rights under patents having claims (a) on the devices themselves and (b) on combinations of the devices with other devices or elements, as for example in various circuits and hook-ups.

"The sale of this device carries a license under the patent claims of (a), but only for (1) talking machine uses, (2) radio amateur uses, (3) radio experimental uses and (4) radio broadcast reception; and only where no business features are involved.

"The sale does not carry a license under patent claims of (b) except only (1') for legitimate renewals and repairs in apparatus and systems already licensed for use under such patent claims on combinations, (2) for assembling by amateurs and experimenters, and not by others, with other licensed parts or devices, or with parts or devices made by themselves, but only for their own amateur and experimental radio uses where no business features are involved, and not for sale to or for use by others, and (3) for use with licensed talking machines and licensed radio broadcast receiving devices; and only where no business features are involved."

RADIO CORPORATION OF AMERICA

Station Log

A table is provided for logging radio stations. Columns include: