Radio mirror (Jan-Oct 1923)

October 6, 1923 RADIO DIGEST — Illustrated 17 First Steps for Beginners in Radio Chapter XIX — Locating Trouble in the Set By Thomas W. Benson, A. M. I, R. E. DEGINNERS will find the accompanying ^* series by Mr. Benson very helpful In learning the rudiments of the popular science of Radiotelcphony. The series will be concluded in our next issue with Chapter XX— Useful Information and Formulas. IN the last chapter we treated the testing of the individual instruments of the Radio set. and this chapter will take up the effect of defective apparatus in the operation of the set. It is practically impossible to cover every trouble that might develop in the operation of a set, but sufficient data will be given to enable one to eliminate the more common troubles and serve as a guide in more difficult cases. When a set refuses to function it is advisable to tackle the problem in a systematic manner. First of all make sure the aerial and ground are connected, the phones connected up, the battery wires properly attached and the tubes in their sockets and lighted. By loosening the phone cord and tapping on the phone post a click will be heard which indicates the B batteries are connected up. If after checking the above no signals are received or the set seems dead, it will be necessary to go to the interior of the set to locate the trouble. Testing Oat Telephones Connect the phones into the plate circuit of the detector tube. If no signals or noise are heard, it may be for any of the following causes: Batteries run down; tube not making, contact in the socket properly; polarity of B battery reversed; telephone defective, phone condenser shorted, or primary circuit not tuned. If good signals are heard in the detector circuit but when switching on the amplifiers the signals are weak, we may look for the following: Tubes not making contact; battery too low to operate amplifiers with detector on; a burned out trans \OEJkLERSl PROMPT SHIPMENTS LIBERAL DISCOUNTS former, or an open transformer or phone condenser Bhorted. If jacks are used they may be making poor contact or shorting transformer primaries. Weak signals in the detector circuit may be due to one or more of the causes that will prevent signals entirely, and also to wrong connection on the tickler coil; grid condenser shorted; open circuit in the grid, or improper adjustment of the tube filament brilliancy and plate voltage when a soft tube is used. By checking all the above when a set refuses to work up to its maximum efficiency, the trouble will usually be located. At least the check will in all cases serve as a guide in locating it. Locating Stray Sounds We may now turn to the problem of locating stray sounds, such as scratching, scraping or popping. When these occur in the detector circuit with the amplifiers turned off, they are due to one or more of the following: If tuning the set changes the noise it is probably caused by excessive voltage on the plate or filament; too large a tickler inductance; irregular oscillation of the set due to poor connection to aerial or ground, and in some cases when too low a capacity is used for tuning, the aerial circuit may make it unsteady and difficult to handle. In the latter case, swaying of the aerial will often affect the set. It. is advisable to use a larger condenser in the aerial circuit to stiffen it and more inductance to again obtain resonance. Popping sounds occur when the grid charge becomes too great and can be remedied by lowering the resistance of the grid leak. When the noises are not affected by tuning, the trouble may be due to any of the causes listed in the last paragraph or 1lh„ cuu. trve-fonneat tvscc&iAt/Dt Radio :iiMfo:fltrcT 123 W. M a d iron Jt. Chicago Saturn 'Above the Ordinary' Radio Products Automatic Plug ° List Automatically perfect connection. Cord 1 tips held in riselike grip; instantly released by ligkt touch on lever. Fully guaranteed. $1 Perfect Jack Crowfoot offset and solder-flux compound on blades simplifies soldering. Nickel-plated base bracket with rounded corners. German-silver blades and sterling silver contact points. List Prices No. 1 — Single Circuit, Open 50o No. 2 — Single Circuit. Closed 55c No. 3 — Double Circuit, Closed 75c No. 4 — Single Filament Control 75c No. 5 — Double Filament Control 80c Write for Folder The SATURN Mfg. & Sales Co. 48 Beekman Street New York, N. Y. 'ALL-AMERICAN" Transformers acknowledged as the "Standard" of Radio Made in three distinct ratios to meet your requirements. Used by leading manufacturers all over the world. Radio Frequency Transformer Audio Frequency Transformer 200 No. Jefferson Jtlhkago, I1L aiA'Amebicaj, to poor connections in and between instruments. Look for loose connections on the instruments, make sure the rheostat is making good contact; that variable condensers are not shorted by dust or warped plates, and that aerial and ground are tightly connected. We must include under this head static, but one can usually tell this after a little experience. There are many types of static, but if the sounds come and go when the set is not touched and are very irregular in occurrence, the trouble can usually be laid to static. Occasionally the knocking or ticking sounds are heard when the amplifiers are switched on and not in the detector circuit. Switch off the detector, and if the WD-11 and WD-12 Tubes Repaired WDII or WD-12 $3.50 C-300 or UV-200 2.75 C-301 or UV-201 3.00 C-302 or UV-202 3.50 C-30IA or UV-201A 3.50 Moorehead Detectors 2.75 Moorehead Amplifiers 3.00 DV-6 or DV-6A 3.00 Also the new UV-199 3.50 NEW DX 1% VOLT TUBES. 4.00 All tubes guaranteed to work like new Mail Orders Given Prompt Attention "24 Hour Service" RADIO TUBE CORP. SS HALSEY STREET NEWARK, N. J. Tubes Sent Parcel Post, C. O. D. sounds continue they are in the amplifier units and may be due to poor connections between instruments, poor contact at rheostats or batteries, or to defective transformers. Howllnjr and Whistling More general are howling and whistling. When they occur in tuning and encountered in the detector circuit with the amplifiers off, excessive feedback, often (Continued on page 20) RADIO BARGAINS STORAGE BATTERIES ft™^ List Price Our Price $17.00 6-60 $9.25 21.00 6-80 11.75 24.00 6-110 14.75 28.00 6-130 18.75 ADVANCE "B" BATTERIES $1.75 22^4 Volt Small $.75 3.00 22% Volt Large 1.45 4.25 45 Volt Small 2.0O 5.50 45 Volt Large 2.90 GENUINE DILECTO X X Bakelite Panels 3/16" thick, any size $0.02 Sq. inch %" thick, any size S0.OI '/a Sq. 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