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Copyright: 1996 - 2024 BSEE - KB3UON RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived... All trademarks, copyrights, patents, and other rights of ownership to images
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Mac's Radio Service Shop: Barney Takes on Color |
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Always the consummate story teller, John T. Frye began his writing career long before his "Carl & Jerry" electronics adventure series that ran monthly for many years in Popular Electronics. His style featured creating a dialog between instructor and student, serviceman and customer, husband and wife, father and son, etc., in order to present an educational experience with back-and-forth inquiry and responses. In the end, the reader learns something about both sides of the situation. In this story, electronics service shop owner Mac reassures technician Barney that given time and patience, he will grasp the circuit concepts of the newfangled color television sets. Barney Takes on Color By John T. Frye
"You mean you notice something different?" Mac, his boss, blandly inquired. "I hope to kiss a pig I do," Barney retorted. "When did you do all this - and why?" "The wife went to visit her sister over the weekend," Mac explained, "and whenever she is gone that darned house of ours seems as empty as a high vacuum rectifier. To get away from it, I came down here to sort of look around when there were no distractions - especially of the chattering, red-headed, Irish variety," he added with a teasing grin. "I'm overlooking that crack - for the time being," Barney retorted': "It's kind of funny how a familiar place seen under different circumstances spotlights things not normally noticed. I immediately saw several changes that cried out to be made; so I spent the whole of Sunday making them. "First, I put up that little shelf right at the end of the service bench. This will now hold the few publications and sheets to which we refer constantly in our work. I call it the 'First Aid Shelf' because the articles on it are calculated to be the ones we shall normally consult before we turn to our service library. For example, there are the four dial-stringing manuals. Nine times out of ten these tell us all we need to know to replace a dial cord, and we do not have to go into our service data files at all. Also there is an up-to-date tube manual giving complete operating potentials, characteristic curves, and base diagrams of all tubes. You know how often we reach for that. Naturally, the latest index to our service information on radios, TV sets, tape recorders, and record changers is here. A glance at this tells us at once if we have information on a particular piece of equipment and exactly where to find it, together with any factory-suggested changes to be made in that particular model. "Our record changer manuals will go here, too. As you know, many manufacturers are pretty careless about listing the make and model number of a changer used in their combination sets-especially when they do not make the changer themselves. In such a case you can often spot a given changer quicker by leafing through the record changer manuals and looking at the pictures than you can by trying to work through service data cross-list-ings. Since about every changer that comes in can stand a minor adjust-ment of the needle set-down points, the tripping mechanism, etc., I think having the manuals right at hand will speed up this work. In addition, there is a sheet showing interchangeable portable batteries of different makes and another giving interchangeable phono cartridges. These allow us to carry a single line of each of these items and still be able to service most record players and portable, receivers that come into the shop-and to do it quickly and accurately. "Finally, there is a good wholesale radio and TV parts catalogue. The illustrations and descriptions contained in this can be a great help to a technician in selecting a needed repair part or tool, even though he does not order from the firm putting out the catalogue. He can see side by side the offerings of competitive manufacturers with concise and accurate descriptions of each product. What's more, the catalogue gives him a good idea of what a fair price for the item should be. An intimate acquaintance with a good wholesale catalogue permits a technician to buy much more intelligently than is possible otherwise." "As I get it," Barney said, "this 'First Aid Shelf' is to contain only the articles we use a lot. It is to be a sort of Reader's Digest of our service library." "That's it exactly," Mac applauded; "and now let's turn our attention to this adjustable lamp clamped to the edge of the bench exactly between our two working positions." "Is that what that is!" Barney marveled. "I thought it was an overgrown modernistic sculpture of a praying mantis." "There is a resemblance," Mac grinned as he looked at the folded, spring-loaded arms holding the deep shade of the lamp. "I firmly believe a service technician can never have too much light - either intellectual or actual - while doing his work. I'm doubly sure of this whenever I cut loose a wrong lead because I can't see clearly. Our overhead bench lights give all the light we need when the chassis is turned upside down, and of course we have various flashlights for looking into dark corners; but most TV chassis must be worked on while they are lying on their sides, and record changer action frequently must be watched while the changer is right side up. This new lamp gives a flood of light exactly where we need it and leaves both hands free at all times. "Just look how it can reach out to any part of the bench and throw the light in any desired direction. That's because those folding arms extend out to forty-five inches and the lamp itself is mounted on a swivel. Notice, too, that while the lamp can be moved into any position with a touch of the finger, it stays exactly where you put it. When you want to watch a record changer going through its cycle, the lamp will get right down on its knees and peer up into the mechanism with you. If you drop something, the lamp will bend over so the bulb is nearly touching the floor to help you look for the dropped object. When you are taking a set out of a cabinet, the lamp will reach away out from the bench and throw a strong light over your shoulder or up into the speaker compartment to aid you in locating screw slots, and so on." "Man, that thing has got more movements than a can-can dancer," was Barney's man-of-the-world comment. Mac passed over this and went on to point out little plastic dishes mounted along the back of the service bench beneath various instruments. "You know what a fan I am for all sorts of special probes to use with our instruments. I think we've got about every kind of probe you can mention, but we've not had a handy way of storing them. They've all been kept in a drawer where they have a nasty way of getting their leads tangled up. In fact, there have been times when you were trying to sort out a probe from this mess where I couldn't be sure if you were doing service work or trying to weave a fishnet. What's more, it was not always easy to remember which probe was designed for use with what instrument. "That's a thing of the past now. Beneath each instrument you see a deep little plastic dish I bought at the dime store. Probes for each instrument are stored in its individual dish. For example, below the vacuum tube voltmeters we have a crystal probe for reading r.f. voltages, a high voltage probe for going up to 30,000 volts, and a peak-to-peak probe. The new v.t.v.m. reads peak-to-peak voltages directly, but this probe lets the older meter do the same thing. Under the signal tracer we have the r.f. crystal probe and the straight-through audio probe. Beneath the scope we have the demodulator or signal tracer probe, the 100/1 voltage divider probe, and the low-capacity probe, together with the single shielded lead that fits all three probe heads. The dish under the sweep generator doesn't hold probes but in it are stored the various special leads that go with this instrument. It is my fond hope that having these probes ready to hand will encourage you-know-who to use them more often. What's more, I want you-know-who to fold the probe leads up neatly and snap rubber bands around them to keep them in place when he is through using them." "Roger from you-know-who. Wilco. Over and out," Barney chanted. There was a brief silence finally broken by Barney: "Say, Mac, I'm having a rough time trying to bone up on color TV. I've been reading everything I can get my hands on, but I just can't seem to nail it down the way I'd like. There seems to be so much repetition, conflicting analogies, etc., in the articles I've been reading that I'm downright confused. It's not that I'm not trying, either. I think about color TV so much that when I go to bed I even dream in Technicolor." Mac chuckled at this as he went over to a cabinet and took out a large bulging manila envelope. "I've been waiting impatiently for you to display interest in color television," he remarked, "but I didn't want you to feel I was pushing you into it. In this envelope is a complete nine-lesson home study course just for you!" "When I finish the course, I'll know all I need to know about color TV, huh?" "Not by a long shot. I intend for you to use this course as a kind of basic framework on which you will hang all the other things you will be continually learning about this fast-moving, far-from-simple subject. I know it will help you to approach color television in the carefully-planned, step-by-step procedure presented by this course; but there are bound to be many points that will not be crystal clear even after the course is finished. That's where your supplemental reading of magazine articles should help. Each writer sees things a little differently and writes about them from a different point of view. By reading what two or three of them have to say on the same subject, you often see quite clearly something that was a big mystery the first time you read about it. "Speaking of magazine articles, I don't think you will find any much more helpful than those written by Milton Kiver in Radio & Television News, starting with the March, 1954, issue. I think he calls the series 'Fundamentals of Color TV.' One thing I like about the articles is that Kiver takes time at the end of several of them to prove mathematically puzzling general statements made in the body of the articles. I think you'll be surprised at how much more useful and informative a series of articles like this seems when you have several of them on hand and can refer back and forth through them and through your course, instead of just reading them one at a time, with a whole month elapsing between readings." "You would help a guy out with his homework if he got stuck, wouldn't you?" Barney suggested slyly. "Yes, if I could. But you've got to remember that when it comes to color TV I'm just a student same as you are; but we'll sure do our darndest to puzzle it out together." Color and Monochrome (B&W) Television Articles
Posted February 20, 2015 Mac's Radio Service Shop Episodes on RF Cafe This series of instructive stories was the brainchild of none other than John T. Frye, creator of the Carl and Jerry series that ran in Popular Electronics for many years. Mac's Radio Service Shop began life in Radio & Television News magazine (which itself started as simply Radio News), and then changed its name to Mac's Service Shop after the magazine became Electronics World. "Mac" is electronics repair shop owner Mac McGregor, and Barney Jameson his his eager, if not somewhat naive, technician assistant. "Lessons" are taught in story format with dialogs between Mac and Barney.
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