ONE DAY Fred Silverman felt too sick to go to Rockefeller Center and be president and chief executive officer of NBC.

So he sent his 3-year-old son Billy to the office in the company stretch limo. What does Billy do while occupying a key power center of American broadcasting?

"Don't ask foolish questions," says Fred Silverman, behind his own desk now and sporting a droll smile. "What do you think he does?Why, he runs the company. Sure. That's how we put 'Supertrain' on the air. I came in one day and the next thing I knew, there it was. I said, 'What is this?' They said, 'Your son scheduled it.'"

He gets the laugh he wanted from this little joke. "I am a bit of a ham," Silverman has confessed. People who have worked with and for him in television might pick a different phrase to describe him -- a paean or a groan of derision. Whatever they think of him, they would probably agree, no one executive has made a bigger mark on television. For better or for worse.

Silverman, 42, is always spoken of in terms of how he is doing his job; at the moment, the consensus is, not as well as he said he would when he took over NBC two years ago. But behind the facade of machine, there is a real person, a guy up from the ranks who dotes on his two kids and has been known to kick elevator doors and who screams imprecations at subordinates and sits in his office roaring with laughter at a sit-com pilot and grumbles that an official hand-out photo makes him look "like a blimp."

In 1978, NBC's TV network was languishing in third place, its radio division was a shambles, and the whole company was suffering organizational and spiritual arteriosclerosis.

Arrives then the king of the Wunderkind, the programming genius, "The Man With the Golden Gut," the gourmet vulgarian, the vidiot savant who made himself a legend first at CBS and then, more spectacularly, during the happiest happy days at ABC, when his scheduling skill and knack for tinkering helped the network upset a 20-year tradition by taking first place away from CBS.

And this titan declares he will make NBC TV the No. 1 network by December of this year. Now, though, that's considered about the world's longest long shot.

Some are saying the bloom is off the Golden Gut. Some are saying Silverman took on more than any mortal should in trying to win two out of three falls with the hopelessly incorrigible old NBC peacock. And some are saying Silverman has become TV's emperor Nero, increasingly desperate and paranoid as he tries to hold a collapsing empire together.

"I feel terrific," said Fred Silverman last week from his office on the sixth floor of the RCA Building. "Do I sound gloomy?" Uh, no. "People in the know don't believe for a second that things are shaky here. Somebody thrown out of here in the past year might tell you something else. But people here have a good feeling. I mean people who count, not some disgruntled employe on the 10th level down.

"There's an optimism and a belief that we're on the right track and we're going to make a big step forward. From an organizational point of view, we have the best organization and the most efficient company of all three networks."

Unfortunately, Silverman said almost the exact same thing a year ago.

"What I said a year ago doesn't in any way contradict my feelings now," says Silverman. "In a year's time there have not been that many staff changes here. The trick is to get all parts of a machine and put them together and make the thing run. There is no substitute for time when you are building an entirely new organizaion."

Naturally, however, there is one grim possibility for the man with the big fat, very American dreams: Time is running out. Silverman now hedges somewhat on his No.-1-by-New Year's Eve prediction, but it's going to come back to haunt him about the time "Jingle Bell Rock" is blatting out of radios again.

"Look," he says, "it's almost impossible not to improve this coming year. Our series are better, we have very strong movies, we've got the World Series and the Super Bowl, and we have the advantage of disarray at at least one of our competitors. So it is highly unlikely there will be no improvement."

Silverman points to such promising new series as "Hill Street Blues," a groundbreaking cop show, "Speak Up, America," a "Real People" spinoff, and "Shogun," likely to be the most celebrated TV mini-series since "Roots."

The big problem now, Silverman says, is moving the first installment of the 12-hour "Shogun" to a place in the schedule where it won't be opposite the two-hour season premiere of "Dallas." He says every time he moves "Shogun," CBS moves "Dallas." The latest date for the "Shogun" bow is Monday, Sep. 15.

"We're going to make this a great season," says Silverman, like a gung-ho coach at halftime. One of the absolutely disarming things about him is, when you hear him say it, you want almost as much as he does for it to be true. Fred Silverman is not widely, warmly liked, nor does he appear to inspire ferocious sentimental loyalties. But for some reason he has in that portly 46-short frame and behind an ambiguous, what-me-worry smile, the spellbinding and magnetizing power of Kathryn Kuhlman and William Jennings Bryan put together.

In a business now run by bureaucrats, Fred Silverman may not be the last tycoon. But he may be the last magician. 'Some Very Bad Luck'

Michael H. Dann, now an executive with Warner Amex Communications and the man who gave Silverman his first major network job at CBS 17 years ago, says of his former protege, "No matter how good you are, you have to have a certain amount of good luck. Freddie has had some very bad luck."

Many of the declines and falls at NBC were in motion long before Silverman came over. ABC had already invented "Good Morning, America" and was making inroads on the long invulnerable "Today Show," now a major crisis center. NBC News was in a state of nose-diving morale and weakening ratings. A unit managers' scandal, involving the misappropriation of production funds, was well under way, only to be uncovered after Silverman's arrival.

And then came Jane Cahill Pfeifer, hand-picked by Silverman as NBC chairman and a reputed source of continual friction within the organization for her three-fisted administrative moxie. This near-perfect example of calamitous miscasting ended disastrously two weeks ago when Silverman, long under pressure to discharge her, did so only after a sordid public tiff in which Pfeiffer insisted she would not be forced out and then said she was being sacrificed to clear the way for Silverman's own renegotiation contract at NBC.

Fabulous Freddie, Pfeiffer claimed, told her he would be following her "out the door" within six months.

Silverman does not want to discuss this Pompeii of embarrassments. "I don't really want to go into who was at fault," he says."I don't think anything like that will ever happen here again. Nobody came out of it well. The past couple of weeks have been brutal in the press. But it served to draw people here closer together. It wasn't the worst thing in the world. I think if you talked to the top executives here, 9 out of 10 would say they are enthusiastic about the future.

"But what do I know?" Thinning Skin

Silverman has grown increasingly sensitive about the way he is treated in the press, so much so that one of his renowned tantrums was thrown at the NBC press department for the way they were telling NBC's story to the world.

Much of the paranoia is completely justified. This is the first summer in three years in which a major magazine has not published a piece blaming Silverman not just for all the ills and idiocies on television but, implicity at least, for most of the scourges that beset the planet Earth. Richard Reeves, in a 1978 Esquire piece, saw Silverman as an insatiable corrupting demon with a secret friendish desire "to program the nation after conquering television."

But in fact, of the major network executives, Silverman bears the most striking resemblance to a human being. Ah, but how frail and how fallible these human beings can be!

When Al Franken, of NBC's impudent "Saturday Night Live," poked a little too much fun at Silverman on a telecast earlier this year, referring to him as a "lame-o" who had failed miserably to resurrect NBC, it was too much for Silverman. During the broadcast he phoned Barbara Gallagher, in charge of late night, and complained. But he did not as was rumored, order her to remove the remark when the taped version of the show was played later for the West Coast.

"I think he was not so much mad as hurt," says former SNL producer Lorne Michaels. "It caught him offguard. He asked, 'Why are they attacking me personally?' He was devastated by it.Al wrote a letter of apology saying it was just in the healthy American tradition of knocking the boss, and that he had nothing personal against him.

"Ultimately, I think it made him look good. NBC was the network you could criticize the boss at. You won't see any Paley jokes on CBS. [Former CBS Inc. President John] Backe did a few at a board meeting, and look what happened to him."

He was fired. By Paley.

"I like Fred," says Michaels. "He's always been relatively straightforward with me. He's a very charming man."

But as with Citizen Kane, there are other views.

"I've known many crazies in this business," says a knowledgeable, long-time TV veteran, "but Fred Silverman is world class in lunacy. He's nuts. He's loco. And he could bring the entire company down with him."

This isn't meant as a psychological analysis; just one response to the way Silverman runs the company -- noisily. His shouting matches are fabled, his temper tantrums said to be frequent. One of his first occurred soon after he joined NBC and was making a closed-circuit presentation to affiliated stations. When the wrong text came up on the Teleprompter, Silverman reportedly began to yell and scream, then stomped back to his office, where he was sweet-talked into returning to the studio.

On one of his early nights at work, Silverman didn't know that the executive elevators in the RCA building were shut at 7 p.m. Since he almost always works later than that, he was dismayed, to put it mildly, when the elevator button failed to produce an elevator. He began to shout curses and kick the elevator door, an insider says, and now he leaves his office after dark, the elevator, by edict, is always there open and ready for him. It whisks him to that stretch limo for the short ride up to his Central Park West apartment.

Silverman is always raving about his "team," but in fact, sources say, he is not a team builder or team player. His wizardry and zeal for programming and promotion compel him to make all the decisions in those areas himself, with subordinate executives reduced to clerical or rubber-stamping roles. Brandon Tartikoff, Silverman's third head of programming in two years (gone is Paul Klein, moved aside was Mike Weinblatt), is seen by Silverman as a mirror image of his younger self and is likely to last only as long as he can tolerate being second-guessed from on high.

Silverman "does not have a tight grip on reality," says a former associate.

And yet, his enthusiasm can electrify people and convert them to Silvermania. One can be sitting in the office of one of the most powerful men in communications history and suddenly be asked to watch a tape of Redd Foxx in "Sanford." Almost the instant the image materializes on Silverman's screen, he begins to radiate delight. He laughs. He slaps his desk. He lights up like Times Square. He makes it all but impossible not to share his pleasure.

The man loves television and he has the incurable hots for his work. Fred Pierce, his former boss at ABC, says Silverman always used to become sick and stay home on the day a new show was to premiere on the air; he got so nervous and tensed-up, he couldn't make it to the office. He was like a parent whose tot is about to star in the kindergarten revue.

Naturally, when you're in a position like Silverman's, when your own glorious reputation has become a gray cloud that follows you around all day threatening to douse you, you are the subject of many rumors: Silverman runs through the halls yelling; Silverman has gone bananas; Silverman hits the Scotch and water before noon and never lets up all day.

"The only rumor that's true is that I have put on a couple of pounds," said Silverman last summer. "But I'm going to take them off." He didn't, and he still has the body profile of "The Little King" in the comic strips.

There are some good people in this business, but there are also some rotten people," he says. "I think any business is the same way. I've met some fine people and also met some people who are absolutely despicable and dishonorable."

Would some in broadcasting put Silverman himself among the despicables? Yes, they would, and they do. And yet he is full of surprises. Last year, when veteran and beloved NBC publicist Ethel Kirsner retired after 25 years at NBC, there was a great loud wonder among staff members about whether the mighty Silverman would make a showing at the modest going-away party thrown by her coworkers. To their surprise, Silverman not only showed up, he stayed for over an hour. Movers and Tummlers

There has probably never been a better-known broadcasting executive than Fred Silverman. He was himself taken aback when an audience at a Bob Hope concert on Long Island gave him a hefty round of applause after Hope introduced him from the stage.

"It shocked the hell out of me," Silverman says. "It was a very strong burst of applause! I thought maybe he'd said, 'Here's Marlo Thomas' or something. I figured somebody would throw a shoe or a sardine can."

Nevertheless, he claims he didn't like being recognized and craves anonymity. He was asked once to explain why so much attention is paid to him. a"I guess there are very few people to write about now," he said. "Ten years ago you had people like Frank Stanton, Mike Dann, Mort Werner, Bob Kinter, Ollie Treyz, Jim Aubrey -- it was a very colorful group. Now, for the most part, there aren't too many individuals.

"You go back 10 or 12 years, there were a lot of movers, a lot of tummlers [busy, noisy organizers]. I don't think there are very many now."

Silverman is also the highest paid executive in TV history, but, allowing himself a rare moment to talk about himself on a personal level, he says a million bucks a year isn't as lush as one might think.

"By the time the government gets through with it, 60, 70 percent of it is gone. It's just outrageous. It doesn't pay to make any money now, they just take it away. Our 7-year-old goes to a private school in Manhattan and it costs more money to send her to that private school than it cost to send me to a college each year. And that was with a dormitory and everything.

"There's rich and there's comfortable. We're comfortable, but you'd be surprised how fast it goes. I am just amazed that someone is a laborer; I don't know how they can get along. It just confuses me."

Silverman says he no longer brings as much work home as he used to. He "very seldom" shows tapes to his wife, Cathy, any more. "Usually she doesn't like what she sees anyway, so, that tends to depress me. I say, 'Jesus, I don't need this negativism.' She's a very tough critic. But she's also got very good taste. She's usually right."

In Silverman's office, on the wall near the door, is a framed, original New Yorker cartoon in which two lumpy people are seated before a television set. The woman turns to the man and says, "Let's watch NBC, for Fred Silverman's sake, the poor dear."

Silverman says, "My aunt would say that; 'Oh let's watch this for poor Fred.' We have a governess at home and she will only look at NBC. I said, 'You don't have to do that, all your favorite shows are on ABC, so watch ABC, watch 'Happy Days,' that's all right. I'll forgive you.' My kids on the other hand, the hell with that. They don't watch that much TV. Melissa plays the piano. You know something? She got tired of it [television] all by herself. She reads.

"We don't look at much TV in the house."

Among the things we will never know is whether television would be even worse today if there had been no Fred Silverman. But since he has taken over NBC, he has shown a convincing desire to earn not just profits but respect. He has to put on cultural programs that were certain ratings bummers like "Live From Studio 8-H" and "NBC Live Theater." He has launched "Operation Peacock," which will bring children's programming of quality to prime time. He has been accused of not adequately supporting Larry Gelbart's experimental "United States," but NBC under Silverman is the only network that would have put that show on the air in the first place.

In television, it's sometimes the third-place network that gets the chance to innovate. The front-runners are too terrified of losing momentum.

Of course, one of Silverman's woes continues to be that he must program against successes he helped create. Growling about the competition last fall, he said, "I mean, nobody is going to tell me that the shows in the ABC schedule are towering triumphs of creativity." But, Fred! You put those shows on the air! "But it -- I think that shows like 'Love Boat' and 'Charlie's Angels' are shows that people are getting tired of."

Silverman still has a picture of Laverne (Penny Marshall) and Shirley (Cindy Williams) in his office at NBC. It is autographed "To Fred, Who Made Us What We Are Today -- Tired!" Last week Silverman wooed away from ABC Ron Howard, the star of "Happy Days," so quickly that Howard will not even appear on the show this fall.

On Thursday, NBC announced it had snagged Rona Barrett -- definitely a viewer draw, if also a nincompoop -- away from ABC and will feature her prominently on "Today" and other programs. Silverman says there will be other monumental acquisitions announced in the weeks ahead.

If Silverman professes incorruptible faith in himself, he is also the first to voice notes of caution when anythings mysteriously starts going well. Reached in his office last fall, after NBC won its first ratings week in years, Silverman did not have to be pried off the ceiling. "Nobody's euphoric around here," he said. "Everybody's got to work twice as hard. You have to operate like you're No. 4. My temperament is such that I say, 'Hey, that's terrific,' and then I start worrying about problems."

Chided for featuring bosomy women in revealing outfits on many of last year's opening series episodes, Silverman said, "Well, that's showmanship. Going in you will use every trick in the book."

Of course there are obvious contradictions here; Silverman, Giver of Culture -- and Silverman, The Panderer. But he still thinks he can mix it all together and, with just one or two hits, draw enough attention to turn the tables at NBC and replace the public's image of a loser network with that of a winner. He simply adores the challenge.

"I think the exciting thing is to see the schedule change shap and form. That was the exciting thing at ABC. To start to see the nights change, and the whole complexion of a network change, to me, that is exciting.

"I think if it happens here, it'll be quite an extraordinary thing. A lot of people think it won't happen. It's better that way. Originally, I came in and everybody said, 'Six months and they'll be No. 1,' which is the dumbest thing I ever heard. Now they're saying it's impossible, which is great. I just hope they keep on saying it's impossible because then, if it happens, my Lord, they'll say, 'What happened here? It's The Impossible!'"

Silverman recalls the counsel of Perry Lafferty, once one of his superiors at CBS, now NBC's West Coast program chief. "He always used to say to me, 'It isn't a religious crusade, Fred,'" Silverman says. "I try to have a good sense of humor about myself. See, that's another thing. There are a lot of people here who like to laugh. And that's good. This used to be such a somber place. People now, their humer is coming out. And that's the only way to get through a day. Gotta have a couple of laughs every day and say, 'The hell with it.'"

Now. Can he work another miracle?

Will he save do it?

Could anyone do it?

He's got to do it.

Somehow, it'll be like 'There's-no-Santa-Claus' if he doesn't.

"No man has worked harder and longer and tried to do better than Silverman," says an admiring Dann. "He's killed himself. He's entitled to a break. He never asked anybody to do anything he wouldn't do 10 times himself. From the moment I hired him, he always wanted to climb the mountain. He won't quit.

"He's like a great fighter in the ring, and he's taking blows from all sides, but he will not throw in the towel. To see him turn NBC around would be great for all of broadcasting."

But do you like him? "You bet," says Dann. "He's a tiger."