Radio Broadcast (May 1928-Apr 1929)

THE SERVICEMAN'S CORNER THE quite numerous problems that beset the serviceman can be cleared up best by a general discussion of them by several workers who have encountered and solved similar difficulties. A half dozen or so suggestions on the elimination of categorical troubles are always better than the isolated experience of any one serviceman. Six servicemen can give their brothers a better idea on how to go about curing a power pack that overheats than any one of them who may have run across only one of the several possible causes of hot transformers. From month to month, as we scan our correspondence, we are going to pick out the more general attributes of poor reception, and put them before the serviceman for open discussion. The topic this month is noise. The serviceman every day runs into complaints of this sort. Needless to say an objectionable noise should not be present in any receiver, and it is often the job of the local expert to eliminate it. Many things may cause noise in a receiver, from proximity to the lighting mains to an ageing rectifying tube. The cures for noise are as many and as varied as its causes. What cases of hum have you run into? What is your general procedure in tracing and rectifying trouble of this nature? Short articles on this subject of hum reduction will be welcome in "The Serviceman's Corner" — and paid for at our usual rates. Service Equipment and Procedure IDEAS on test equipment and the procedure of locating radio troubles are about as diversified as the possible ways of making stuffing for chicken. The tools and methods vary with the individual. It turns out that this business of fixing a radio set is rather a personal affair, and is cut and dried only in its fundamentals. This departmenthas received many contributions from servicemen, describing their favorite equipment and their systems of using it. While, offhand, it might appear that the selection of the proper tools, and the knowledge of how to use them would be kindergarten stuff to the readers of these pages, so much interest has been displayed in the matter, as is evidenced by the many contributions on the subject, that we feel justified in publishing the more representative letters, and drawing from them such conclusions as we can. SUGGESTIONS FROM KANSAS Raymond E. Snoddy, of Leavenworth, Kansas, boils it all down in a few paragraphs: "When I am making a service call this is the equipment which I use: a meter with a range of 0-50 volts and 0—35 amperes, a long and a short screw driver, two pairs of pliers, file, soldering iron, headphones, hydrometer, test leads, tape, pipe cleaners, spare wire, a large cloth, and a tube and set-tester. The tube and set-tester consists of a 0-8 d.c. filament voltmeter, 0-300 high-resistance plate voltmeter, a 0-15-100 milliammeter, and an a.c. voltmeter with a range of 0-15-150 volts. The tester is also supplied with a cable and tube bases to make the various tests. This equipment is all contained in a small carrying case, very compactly and neatly arranged. I designed and built this service kit myself. "When servicing a radio receiver this is the routine I always go through: First, upon entering the house and while checking the battery connections, I ask the owner a series of questions as to how the set has been acting, how long it has been out of order, etc. This will often save a lot of trouble as the owner will generally give you some information that will point directly to the trouble. I then check the A and B-battery connections, test the batteries, and then place the plug from the tube tester in the first radio-frequency socket and test all the tubes in this socket. I then remove the plug and place it in each socket and note the plate and filament voltages, and also the plate current which tells at a glance if the plate, filament, and grid circuits are all complete. Next I replace the loudspeaker with headphones and inspect the antenna and ground connections. Any further continuity tests are very seldom necessary." ANOTHER SERVICEMAN'S IDEA Bor Brooke, of Minneapolis, Minn., goes into more details, and a bit of reminiscence. "Here I am sort of down with the flu or something and I figured it would be an opportune time to scribble a couple of lines to you The Weston tube-checker is an excellent piece of shop equipment for the dealer-serviceman. Any 4 or 5 prong tube may be tested with this set about the "Serviceman's Corner." Among other things I am a radio serviceman, and as some satisfied customers think I'm not so bad as a serviceman, I thought possibly I had a chance of getting a line into the " Serviceman's Corner." The other things I am are: amateur radio operator — w9dsh-w6awr, commercial radio operator, wgdj-nog, salesman (house-tohouse once when broke and in a small town on the Pacific coast while waiting for my ship to come in), broadcast operator, knrc, radio engineer in a B-power imit manufacturing company. So now that I've explained myself I'll start on some ideas I have on radio service. "First, I will give a list of what I consider about the minimum of tools for a serviceman out on the job: 1. A good test kit for a.c. and d.c. sets. 2. A flashlight (I find Burgess snaplights to be the handiest). 3. A kit of tools containing: a. several sets of good pliers and cutters of various sizes b. several assorted screw drivers c. a complete set of spintites d. a rat-tail and several small files e. a pair of phones f. a few fine drills and a hand speed drill g. a box of assorted screw nuts and junk 4. A bakelite balancing stick with a hex hole A" "The test kit has two uses, it gives the customer a higher impression of the serviceman from the start and it makes a positive and quick check of the set and nearly all the circuits in the set as well as testing tubes, voltages, etc. It is the best investment a serviceman can make for himself and often gives or loses you a job. I found mine handy once when I was stranded on the Pacific coast and didn't know when I woidd get a ship. I took my test kit and made house-to-house canvass in a district that was bound to be good. I offered free tests on the customer's tubes and batteries and told them truly just the condition of their set. In case they needed anything invariably they bought it from me. I also had a Sterling tube rejuvenator along and brought their tubes up for two bits apiece. I also sold several sets during the month I worked the district, and although it was hard work and very discouraging at times it was better than going hungry. I played the game fair and square, made a good many friends, and worked up a good little business that I passed on to a friend whom I had met — that was another example of the helpfulness of a test kit. "The Burgess snaplight is the handiest little light for a serviceman that I have ever seen as it gets into small places and you hold it in your hand and work with the hand too. I buy them by the half dozen as I lose them or leave them all over town. They cost 26 cents apiece wholesale and last two weeks if you don't lose it in a day or two. "As for the tools, that is another thing that a customer looks at when the serviceman arrives. A neat kit and a good clean set of tools makes a great impression on the average set-owner." • april, 1929 page 389 •