RCA 50 User manual

RCA
Radiola 50
REG, U.S. PAT, OFF.
"AC " Socket-Powered
50 to 60 Cycles, 105 to 125 Volts
INSTRUCTIONS IB-50
Radio Corporation of America
233 Broadway, New York City
100 West Monroe Street 235 Montgomery Street
Chicago, 111. San Francisco, Cal.

Fig. l—RCA Radiola 50

RCA
Radiola 50
REG. U.S. PAT. OFF,
"AC" Socket-Powered 50 to 60 Cycles,
105 to 125 Volts
Instructions
INTRODUCTION
RCA Radiola 50 is a batteryless, antenna type radio receiver, entirely socket-power
operated and contained in a cabinet complete with loudspeaker. It employs the well known and perfected tuned
radio frequency circuit, with three stages of radio frequency amplification, a detector, and two stages of audio
frequency amplification.
The new "AC" Radiotrons introduced by the Radio Corporation of America are employed in RCA Radiola
50. "AC" Radiotrons UX-226 are used in the first audio-frequency and in all radio-frequency stages. "AC"
Radiotron UY-227 functions as the detector. Fine quality of reproduction and ample volume arc insured by the use
of power-amplifier Radiotron UX-171-A, in the final audio stage, in conjunction with the built-in RCA
Loudspeaker 100-A.
RCA Radiola 50 may be connected to any alternating-current circuit within the limits of 50 to 60 cycles and
105 to 125 volts. The socket-power unit, contained within the Radiola cabinet, furnishes alternating current to all
filaments, as well as "B" and "C" voltages for all Radiotrons in the receiver. "B" and "C" supply is provided by
means of the new rectifier Radiotron UX-280.
This Radiola has but one selector for locating stations and is, therefore, extremely simple to operate. A pilot
lamp illuminates the Selector Dial and serves as an indicator to show when the power is "ON".
Excellent sensitivity and selectivity are provided over the range from 550 to approximately 1400 kilocycles
(545 to 214 meters).

Part I—Installation and Operation
EQUIPMENT
Furnished—
1. Pilot lamp parts (packed in the instruction book envelope) as follows:
One pilot lamp, Type T-3 MAZDA,miniature base, 6 volts, 0.15 ampere.
One pilot lamp canopy.
2. One complete set of Radiotrons, as follows:
Four RCA Radiotrons UX-226.
One RCA Radiotron UY-227.
One RCA Radiotron UX-171-A.
One RCA Radiotron UX-280.
3. One 8-foot power cord with attaching plugs.
To Be Provided—
1. Antenna and ground equipment (refer to pages 8 and 9).
Fig. 2 Rear View with Door Open

4

INSTALLATION
Preliminary—After removing RCA Radiola 50 from the shipping container, open the rear door. Unwrap the
power cord and the antenna and ground leads. Plug the power cord into the bottom of the power connector, and
see that the plug on the short cord from the Socket Power Unit is properly inserted at the top of the power
connector, as shown in Figure 2. Pass the antenna and ground leads out through the holes provided as shown in
Figure 2.
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 is dependent upon proper installation of the antenna
and ground. (See pages 8 and 9.)
Connect the antenna lead (blue) of the Radiola to the lead-in wire, and the ground lead (black with
blue tracer) to the ground wire (see Figure 2). Both connections should be soldered and insulated.
Pilot Lamp—Screw the pilot lamp securely into the socket above the Selector Dial. Insert the
prongs of the pilot lamp canopy into the slots above the dial and turn the canopy in the clockwise
direction until it locks in place. (See Figures 3 and 4.)
Important—Never apply power to RCA Radiola 50 unless all Radiotrons are in the sockets.
Radiotrons—The Radiotrons should always be handled carefully. Remove the red paper label from
over the UX-171-A socket. Insert the seven Radiotrons in the proper sockets, as shown in Figure 2. Be
sure that the "UX" Radiotrons are faced so that the two large pins enter the large holes, and that the base
of each Radiotron rests squarely against the socket.
Care should be taken not to insert a UX.-226 Radiotron in the UX-171-A socket, as the higher
filament voltage will burn out the UX-226 Radiotron.
Loudspeaker—See that the connections of the loudspeaker cord are secure at the loudspeaker
terminals (Figures 2 and 6).
Power Supply—RCA Radiola 50 should never be connected to any circuit supplying other than
alternating current, within the limits of 50 to 60 cycles and 105 to 125 volts. Failure to observe this may
result in damage to the Radiola. If there is any doubt about the rating of the house lighting circuit, consult
the Electric Light and Power Company before connecting the Radiola.
The Voltage Switch, Figure 5, has been previously set at the "120 V." position and should not be changed unless it is definitely
known that the supply is always below 115 volts. (See "Voltage Switch" Part II.)
5
Fig. 3—Selector Dial Showing Canopy
Removed and Pilot Lamp in Place

Insert the attachment plug of the power cord in an electrical outlet. Set the Power Switch (Figure 4) to the
"ON"position, and make sure that the seven Radiotrons and the pilot lamp are lighted. (If they are not lighted,
refer to "Power Supply", Part III, page 9, for further instructions.) When sure that all Radiotrons are lighted, snap
"OFF"the Power Switch.
OPERATION
To operate RCA Radiola 50, refer to Figure 4 and proceed as follows:
1. Set the Power Switch to the "ON"position. The pilot lamp should light. An interval of approximately 30
seconds is required for Radiotron UY-227 to heat before satisfactory reception is possible.
2. Turn the Volume Control to the extreme "LOUD"position.
3. Turn the Selector slowly in either direction until a station is heard; then adjust for maximum signal
strength.
4. Adjust to the desired volume by means of the Volume Control.
5. When through operating, snap the Power Switch to the "OFF"position.
6

Fig. 5—Socket Power Unit with Terminal Cover Removed—Showing Voltage Switch
Part II—General Information
The following suggestions are offered to assist the user in obtaining the best performance from RCA Radiola
50. Voltage Switch—Where the supply is always below 115 volts, improved reception with normal life of the
Radiotrons will be obtained if the Voltage Switch (Figure 5) is set at the "110 V". position. To determine whether
the supply is below 115 volts, consult the RCA Authorized Dealer or the Electric Light and Power Company.
The Voltage Switch is accessible by removing the Terminal Cover (Figure 2). Before removing this Cover,
the Power Switch (Figure 4) should be set in the "OFF"position and left in this position until the Terminal Cover is
replaced.
Power Supply—Reception may possibly be improved by reversing the attachment plug (Figure 6) at the
electrical outlet.
Radiotrons—Improved results may sometimes be obtained by rearranging the UX-226 Radiotrons, all other
Radiotrons remaining in their respective sockets. Before interchanging these Radiotrons, switch "OFF"the power.
(See "Important", page 5.)
Volume—Reduction of volume should be accomplished by adjustment of the Volume Control rather than by
the Selector, except for local reception when the volume may still be greater than desired with the Volume
Control in the extreme "soft" position.
Selector Dial—The dial scale is arbitrarily graduated from "0" to "100". The shorter wave length (higher
frequency) stations are received toward the zero end of the scale. The dial settings may be recorded on the Station
Log, at the rear of this book.
7

Fig. 6—RCA Radiola 50 Cabinet Wiring
Antenna
(a) Outdoor Type—A single-wire outdoor antenna, 25 to 50 feet long, will usually be sufficient for good
reception. A short antenna is preferable in a locality where broadcast stations are numerous, whereas a longer
antenna may give improved results in a locality distant from such stations.
The antenna should be isolated from other objects and as high as possible. It should be erected
at right angles to all electric light and power lines and must not cross either above or below such lines. The
antenna and lead-in should be supported by high-grade glass or glazed porcelain insulators, and the lead-in should
be a foot or more from the building. All splices should be soldered.
8

The lead-in and ground connections should be as short and direct as practicable. It is preferable that the
lead-in wire be a continuation of the antenna itself. Where brought through the wall or window frame it should be
insulated therefrom, preferably by means of a porcelain tube.
An outdoor antenna should be protected by means of an approved lightning arrester, in accordance with the
requirements of the National Board of Fire Underwriters.
(b) Indoor Type—An indoor antenna is not as effective as a properly installed outdoor antenna. Where the
installation of an outdoor antenna is not practicable, satisfactory results may be obtained by using about 20 to 40
feet of insulated wire inside the building. The size of the wire is not particularly important, though No. 18 bell
wire is suggested. In buildings with metal lath, satisfactory results are not always possible with this type of
antenna. Under such conditions, various arrangements of the indoor antenna may be tried.
Ground—A good connection to ground is as important as a well constructed antenna. Definite instructions
cannot be given, as conditions vary in different locations. Water pipes or steam pipes generally make good
grounds. The use of gas pipes should be avoided. The ground lead should be connected by means of an approved
ground clamp to a section of the pipe that has been scraped thoroughly clean. If water or steam pipes are not
available, a pipe or metal rod may be' driven into the ground to a depth of several feet. The success of this type of
ground depends upon the presence of moisture in the soil.
Part III—Maintenance
Radiotrons—Before inserting or removing Radiotrons, always be sure that the Power Switch is in the "OFF"
position. (See "Important", page 5.)
The contact pins of the Radiotrons should be inspected occasionally and kept clean.
It is a good plan to have available at least one new RCA Radiotron of each type. Periodically, the condition
of each Radiotron in use should be checked by substituting a new one and comparing results in reception, both
local and distant.
Power Supply—Should the pilot lamp and Radiotrons fail to light with the Power Switch in the "ON"
position, it is probable that the Radiola is not properly connected to the power supply. Make sure (1) that the
attachment plug is properly inserted in the electrical outlet;
(2) that both the upper and lower attaching plugs are properly inserted at the power connector;
Figure 2; and (3) that the current is not switched off at any point.
Volume Control—If the operation of the Volume Control should at times produce a grating sound in the
loudspeaker, this may be remedied by turning the knob back and fourth between the extreme positions a few times
in order to remove any foreign material which may have collected 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 an accumulation of dirt or soot on the antenna insulators.
Pilot Lamp—Renewal bulbs (see "EQUIPMENT"—Furnished, page 4) may be purchased from any RCA
Authorized Dealer.
RCA Authorized Dealer—If further service is necessary, the RCA Authorized Dealer from whom the
Radiola was purchased should be consulted.
9

NOTICE
The apparatus and devices which, or the use of which, are covered by patents arc sold only under certain
specified licenses set forth in a notice attached permanently to the said apparatus and devices, or if this is
impracticable on account of size, then on tags or wrappers attached to the said apparatus and devices or on the
cartons containing the same. This license notice is as follows:
"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 0)for use with licensed
talking machines and licensed radio broadcast receiving devices; and only where no business features are
involved".
RADIO CORPORATION OF AMERICA
Important
The RCA 90-day guarantee on this Radiola is not effective unless the RCA Guarantee Tag is
countersigned at time of sale by the RCA Authorized Dealer from whom it was purchased. If you have not
received the signed Guarantee Tag, be sure to have the RCA Authorized Dealer give it to you immediately.
10

STATION LOG
Date
Call Letters
Location
frequency in
Kilocycles
Wave Length
Selector Dial
Setting
'

STATION LOG
Date
Call
Letters
Location
Frequen
cy in
Kilocycl
es
Wave
Length
Selector
Dial
Setting
• .
Printed in U.S.A.