Red and Fuzzball on Convergence
January 1958 Radio-Electronics

January 1958 Radio-Electronics [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

I'm not sure when storytelling as a style of technical writing went the way of vacuum tubes (probably about the same time, come to think of it), but this article from the January 1958 edition of Radio-Electronics is a prime example of how such prose was utilized. Two characters, Red and Fuzzball, meet at a coffee counter and discuss the intricacies of color convergence in color television sets. Such issues are not a concern with today's electron-beam-less displays, but back in the day, it made the difference between an acceptable picture and frustrating images with color fringing. Maybe you remember those days. After having read many articles on troubleshooting, repairing, and aligning TV sets prior to LCD and LED displays, I have a real appreciation for the knowledge of really good repairmen. In some ways the vacuum tube sets were easier to troubleshoot because the tech could easily pull tubes from sockets to make voltage and resistance readings rather than needing to unsolder transistors or ICs.

Red and Fuzzball on Convergence

By Robert G. Middleton

Fuzz is still learning about color TV - the hard way

Have I still got a job?" asked Fuzzball anxiously, as he sat down beside Red at the counter. "Take it easy," Red replied. "Old Fatpants is late himself this morning - he don't even know that you didn't show."

Fuzz' hand shook visibly as he reached for the cup of coffee. "So where you been, anyhow?" Be asked curiously.

"It worked out to be sort of a lost weekend for me," Fuzzball explained. "I took one too many and ..."

"There are times," Red chuckled, "when Fuzz lives in a world of his own."

"There ain't no such world," Bess snorted, and flounced off.

"There was a good reason for me falling off the wagon though," Fuzz said in self-defense.

"Always is," Red agreed. "What's yours?"

"It's that installation out on the South Side," said Fuzz. "Line voltage drifts up and down so much that I can't converge the picture tube for sour apples."

"That's easy," replied Red. "All you got to do is put in an automatic line-voltage regulating transformer."

"That's easy?" Fuzzball asked. "This guy won't even buy an outdoor antenna. I can't get him off my back."

"Lord have mercy," Red breathed. "The penny-pinching public again."

"What can I do?" Fuzzball asked helplessly.

"Ignore him," Red advised.

"Suppose he calls up Old Fatpants and complains?"

"Let him. I'll talk to Fatpants. I been on these hey-rube runs before."

"Red."

"What now?"

"Can you cash me a check?"

"The answer is no. Here's a fin I'll give you. That way nobody ain't kidding nobody."

"Thanks, Red. I dunno what I'd do without a buddy like you."

"I know what you'd do - and so do you."

A Shortcut?

Not to change the subject but I got a new way to converge a picture tube that I like better."

"What's that?"

"When I start making the vertical dynamic, I kill the red gun and line up the green dots with the blue dots."

"Nothing wrong with doing it that way, if you want to."

"The way you started me out," explained Fuzzball, "I left the red gun on. It's less complicated to adjust the green by itself."

"At the beginning, yes," Red agreed. "But it's a sure bet that after you get some more experience, you'll be leaving the red gun on."

"I suppose you're right," Fuzzball remarked. "Right now, it seems easier to work with two colors at a time."

"After you get experience," Red explained, "you'll learn to pay no attention to the colors you're not working with. It will just be a bother to you, then, to be turning guns off and on."

"I see what you mean," Fuzz replied. "Tell me this," said Red, "do you keep the green and blue dots converged in the center?"

"I took your hint before, Red. I use crosshatch to start the job and I found it's easier that way."

"Thought you would."

"But I don't keep the green and blue lines converged at the center unless I'm working in a real dark room."

"You're learning fast."

"Hope so," Fuzz replied. "I found that when there's light shining on the screen, it's easier to judge if the green and blue lines are straight with each other if I keep them separated a little bit." (See Fig. 1.)

"Most techs would agree with you on that one," Red assured him.

"One thing the set manufacturers have done that really helps on this convergence, though."

"Namely?"

"They are either mounting the dynamic controls on the front of the set or on a box that you can bring around to the front."

"You can say that again. It's cut convergence time just about in half."

"OK. I will say it again," Fuzzball grinned.

"You're a real character," Red replied disgustedly. "But what are you doing after you line up the green and blue vertically?"

"Well, then I kill the green gun and turn the red gun back on."

"That's OK."

"I adjust the red beam magnet or the blue lateral corrector to separate the red and blue lines a little bit."

"What next?"

"Just like the green. I adjust the red vertical amplitude and tilt controls to make the red and blue lines straight with each other up and down the screen." (See Fig. 2.)

"I hope you mean you are watching just the vertical center column on these vertical adjustments," Red interjected.

"What do you think I am. Stupid?" Fuzzball asked.

"I'd rather not answer that question yet," Red observed. "Then what next?"

"That's when I turn the green gun back on and check to see whether the green light is still straight." (See Fig. 3.)

"A little green touchup might be in order," Red agreed.

Finishing up

"Finally, I adjust the beam magnets and the lateral corrector to bring the three color lines together and make a white line."

"How's your luck running?" "Sometimes there's a little tattle-tale color showing at the top or bottom," Fuzzball admitted.

"You'll never get it 100% perfect," Red reassured him. "We discussed that before."

"But you can't see it very far back from the set," Fuzz said.

"Better hadn't, at viewing distance anyhow."

"It's a funny thing," Fuzzball mused, "when there's a little color showing at the top of the white line, the dynamic adjustments will shift the color fringing to the bottom of the line, or to the middle. But you got to leave a little fringing somewhere."

"You're getting hep," Red remarked, "and just where do you leave the fringing?"

"Does it make a difference?" Fuzz asked innocently.

"Sure does. You'll have lots less complaints if you leave the final fringing at the bottom."

"But why should that be?" asked Fuzz.

"Simply because programming usually carries the action above center screen - that's where John Q. Public looks the most."

"I got to admit it makes sense," Fuzzball agreed.

"Now what next?"

"That's when I switch over to white dots and work on the blue amplitude and tilt controls."

"You can keep on with the crosshatch if you want to," Red advised.

"How would you do that?"

"Well, the crossovers on the hatch give you the same use as dots."

"I guess they would, at that."

"So you can look up and down the vertical center line, and see how the crossovers are doing."

"It always looks OK at the center of the screen," Fuzzball reminded him.

"That's right. The static adjustments make it easy to bring the center in."

"But the crossovers are pretty cruddy at the top and bottom of the screen."

Now the blue

"Right again. So you should open up the blue vertical amplitude control wide and adjust the blue vertical tilt to get the same blue separation at both the top and bottom of the screen."

"You get away from the dot routine on this deal," Fuzz remarked.

"Naturally, because you're working with a different type of pattern."

"Well, after I get equal blue line spacing at the top and bottom, where do I go from there?"

"Next thing you do is turn down the blue amplitude to get equal blue line spacing all the way up and down the vertical center column."

"But I might have to touch up the blue tilt adjustment," Fuzzball suggested.

"Only a miracle could save you," Red agreed. "There's quite a bit of interaction."

"And, then, when the blue lines are spaced exactly the same amount from the yellow lines all the way up and down the center column, the static adjustments would give final vertical convergence."

"Fuzzball, there are times when you are so bright you dazzle me," Red said effusively. "Permit me to buy you another cup of coffee."

"That's coffee?" Fuzzball exclaimed, ducking agilely as Bess heaved a creamer at him.

"We can use crosshatch all the way on the horizontal dynamic convergence too, if we want to," Red added.

"How about giving me a rundown?" Fuzzball suggested.

"Well, you started off by telling me how you kill the red gun when you start the vertical. So you can start the horizontal the same way, killing the red gun."

"Makes it easier to remember that way," Fuzz observed.

"Then," continued Red, "turn the green horizontal amplitude and the green horizontal phase at the same time and get the green crossovers on the same side of the blue crossovers. Get the crossovers the same, all the way along the horizontal center line."

"Guess I might need to hit the beam magnets or lateral corrector a little to separate the green and blue," Fuzzball suggested.

"But definitely," Red agreed, "and positively if there is much light in the room."

"So after I get the green crossing all on the same side of the blue crossings, where do I go from there?" Fuzz asked.

"Then you get down to fine points," Red explained. "Look at the spacings between the green and blue crossings. You'll find it's dollars to doughnuts that the spacings aren't all exactly equal amounts."

"So I suppose I got to touch up the green amplitude and phase to make all the crossover spacings the same."

"Posilutely. Then, you do exactly the same thing for the red crossovers. Kill the green gun and turn on the red gun. Adjust the red amplitude and phase to get equal crossover spacings, with all the red crossings on the same side of the blue crossings."

"That makes a pretty good routine for remembering," Fuzzball remarked. "What do I do next?"

"Turn the green gun back on. Both the red and green crossovers will be pretty near even from the blue crossovers. A little touchup on the red and green controls should do it about right."

"What about the blue horizontal dynamics?" Fuzz asked.

"I'm getting to that," Red replied.

"But, first, you want to make sure you are satisfied with the job so far. Get on the static adjustments and make the pattern white in the center of the screen. Then, you might want to do just a little more touching up to get real good crossovers at the same points all along the horizontal center line."

"Then I go to the blue horizontal controls?" asked Fuzz.

"Absotively. Now we straighten up the blue line and bring it in with the yellow line."

"So far, I've always been resonating the blue phasing coil," Fuzz ventured.

"Saves time," Red agreed. "You should do it on this all-crosshatch routine also. Open up the blue horizontal amplitude and adjust the blue horizontal phasing coil for a peak, smack in the center of the screen."

"That's just like we were using dots." "Right. Then, back off on the amplitude until the blue line is as near parallel with the yellow as possible."

"But I'll probably need to touch up the blue phasing here."

"You're reading my mind," Red stated. "The touchup will give the parallel spacing you're looking for between the blue and yellow lines."

"And the static controls will give me final overall convergence," Fuzz suggested.

"Just about," Red agreed. "But there are a couple of little points to keep in mind."

"Such as?"

"Look carefully at the vertical convergence. You might have knocked it out a trifle, and need to touch it up a wee bit."

"Anything else?" asked Fuzz.

"Yep. Check the corners of the screen. There's no adjustment here, but sometimes if you see a little fringing in the corners, you can compromise a little to improve it, without hurting other parts of the screen noticeably."

"Whoof!" exclaimed Fuzzball, blowing hard. "And I took up television for a living. I could of had a job in a putty-knife factory and nothing to worry about."

"Maybe you could get a job as a pilot on a rocket to the moon," Bess suggested.

Fuzzball rose to his feet. "Give the gal her money, Red, and let's get out of this booby trap."

Bess banged another creamer on the door behind the fast-moving Fuzzball's back.

Posted May 31, 2019
(updated from original post on  2/4/2014)