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RCA
Radiola 21 and Radiola 22
SERVICE NOTES
RCA Radiola 21
First Edition—30M
Copyright October 1929
-
OF
RADIO
VICTOR CORPORATION
AMERICA
233 BROADWAY, NEW YORK CITY
DISTRICT SERVICE STATIONS
BROOKLYN, N. Y.
CHICAGO, ILL.
SAN FRANCISCO. CAL.
Bldg. No. 19—168 - 39th St.
2001 West Pershing Road
274 Brannan St.
DALLAS, TEXAS
ATLANTA, GA.
Santa Fe Bidg., Unit No. 2
150 Peters St.
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Related Manuals for RCA Radiola 21
Summary of Contents for RCA Radiola 21
- Page 1 Radiola 21 and Radiola 22 SERVICE NOTES RCA Radiola 21 First Edition—30M Copyright October 1929 RADIO VICTOR CORPORATION AMERICA 233 BROADWAY, NEW YORK CITY DISTRICT SERVICE STATIONS BROOKLYN, N. Y. CHICAGO, ILL. SAN FRANCISCO. CAL. Bldg. No. 19—168 - 39th St.
- Page 2 Subsequent service and repair may be required by reason of wear and tear and mishandling, to the end that RCA Loudspeaker and Radiola owners may be entirely satisfied.
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Page 3: Table Of Contents
Broken Condenser Drive Cord— ——----- 7 Service Data Charts—--——-————….— 8-9 PART HI—ELECTRICAL TESTS Testing Condensers ——------—------—---- 10 Socket Voltages Radiola 21 or 22---—------ 10 Voltage Readings -—-—-——--—.——.— 10 Radiola 21 or 22 Continuity Tests-—------- 11 Continuity Test Charts ————— 13-15 PART IV—MAKING REPLACEMENTS... -
Page 4: Antenna (Indoor Or Outdoor)
ANTENNA RECEIVER ASSEMBLY GROUND LEADS BATTERY REPRODUCER CABLE UNIT Figure 1—Rear interior cabinet view of Radiola 22... -
Page 5: Rca Radiola
RCA RADIOLAS 21 and 22 SERVICE NOTES Prepared by RCA Service Department STATION RADIOTRON SOCKETS SELECTOR DIAL FOR A.F. STAGES STAGE SHIELDS VOLUME CONTROL LOCAL-DISTANT SWITCH OPERATING SWITCH Figure 2—Top view of receiver chassis showing location of some parts ELECTRICAL AND PHYSICAL SPECIFICATIONS Type of receiver—Screen Grid Tuned R.F. - Page 6 INTRODUCTION RCA Radiolas 21 and 22 are battery operated screen grid radio receiving sets. Radiola 21 is a table model and Radiola 22 is a console model employing the same receiver chassis and the mechanism of RCA Loudspeaker 100B. RCA Screen Grid Radiotrons UX-222 are employed as radio frequency amplifiers, Radiotrons UX-112A as the detector and first audio and UX-112A or UX-171A as the power stage.
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Page 7: Antenna System Failures
(f) The operating switch disconnects the filament battery and the "B" voltage to the volume control. This prevents unnecessary "B" battery consumption when the receiver is not in use. (g) A fixed regenerative detector gives added sensitivity to that circuit with a resulting gain in over-all sensitivity. -
Page 8: Service Data Charts
SERVICE DATA CHART The following service data chart indicates various troubles by their symptoms and gives the specific remedy necessary. Indication Cause Remedy Defective Radiotrons Replace defective Radiotrons Defective Operating Switch Replace defective operating switch Defective Volume Control Replace defective volume control Wrong battery connections Connect battery correctly. - Page 9 Check mounting of loudspeaker of Radiola 22 and Loudspeaker mounting make sure it is properly supported Do not place loudspeaker too close to Radiola 21. Acoustic Howl Increase its distance to the receiver or change the relative angle between the loudspeaker and the...
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Page 10: Testing Condensers
5.4 for a battery or 1.8 per cell under load. SOCKET VOLTAGES RADIOLA 21 OR 22 Radiotron UX-171A used in last stage with 135 volts plate supply. For other power tubes or plate voltage the change will be in last socket Figure 5—Internal connections of A.F. -
Page 11: Radiola 21 Or 22 Continuity Tests
This may be done by means of a direct reading "Ohmmeter," a resistance bridge, or any of the methods shown in previous issues of RCA Service Notes. The Radiotron contacts and socket numbers, the cable connections and color scheme are shown in Figures 7 and 8, and should be referred to when making these tests. - Page 12 OPERATIN6 LOCAL-DISTANT TO GROUND TO ANTENNA SWITCH SWITCH B+ PWR B+AMP. 135 V. B+ 67 V. C-AMP. 9V. C-PWR. A-6V Figure 7—Radiola 22 battery cable and external connections of receiver assembly and reproducer unit...
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Page 13: Continuity Test Charts
CONTINUITY TEST CHART Unscrew Pilot Lamp Before Making Test Circuit Test Terminals Correct Effect Incorrect Effect Indication Caused by Grid CG1 to Ground Closed (3 Ohms) Short former Shorted tuning or trimming condenser SG1 or SG2 to Closed (50,000 Open Open volume control or connection Ohms) B+67(Maroon) Vol. - Page 14 Figure 8—Wiring diagram showing color code and connections...
- Page 15 CONTINUITY TEST CHART—Continued Unscrew Pilot Lamp Before Making Test Circuit Test Terminals Correct Effect Incorrect Effect Indication Caused By —Fl to Ground Filament Closed (6.5 Ohms) ,0pen Short Open UX-222 filament resistor or connection Shorted .1 mfd. condenser —P2 to Ground Closed (6.5 Ohms) Open Open UX-222 filament resistor or connection...
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Page 16: Removing Chassis From Cabinet Of Radiola
(1) REMOVING CHASSIS FROM CABINET OF RADIOLA 21 To remove the receiver chassis from the cabinet .of the Radiola 21, proceed as. follows: (a) Release the local-distant switch a id the operating switch from their respective escutcheon plates.