Technophrenia is the state of being delighted at the possibilities of new technologies and, simultaneously, horrified by the possibilities of new technologies. There is no known cure, but a rather Trinitronic therapy has been found. All you have to do is buy a Sony KV-2643R, which is to television sets what a 240SLC is to Mercedes Benzes. It's a dream machine. You turn it on and technology is your firend.

You turn it on and even television is your friend. Of course, there's nothing worth watching, but if there were - oh boy oh boy, would this be the set to watch it on. Sony's KV-2643R Trinitron color console (and the 2644R, which sports a white, rather than a pecan, body) has a 26-inch screen, the biggest ever distributed in the United States, and a picture quality, though slightly distorted at the top, as good as on the smaller Sony's, which is to say, the best that can be bought.

But in addition, the set has a new, refined, infra-red remote control that can do things previous Sony remote controls couldn't. You can punch up with its silent buttons any of 14 channels without going sequentially through the roster, or you can cruise the airwaves with another button that moves the channel selector forward or backward. You can raise or lower the volume and turn the set on and off, as you would expect, but you can also press a little "mute" button to cut off completely the sound during commercials and Barry Manilow specials.

The kick to be gleaned from squelching a yammering announcer or bully-boy sportscaster is almost indescribable. If only there were a way of letting them know you had just rendered them speechless, the plastic little magpies.

You can't adjust the color with the remote control, but then, you don't really need to. The set tends to do the adjusting for you. It's such a big bright and accurate picture that watching TV turns resonant with revelations.At last you can read the tiny type in the McDonald's ads and the EPA mileage estimate disclaimers on the auto commercials. You can see what a good job they do making up Walter Cronkite (he looks just like Walter Cronkite). You can even see the little woman in the corner of the screen making with the sign language on the religious programs and the Ex-Lax ads.

And movies really l0ok like movies; they're big, they're detailed, and if the print is good, the Technicolor glistens. Of course, if the print is bad, as it often is when a local station slops an old movie across the screen, Sony-boy makes this deficiency all the more apparent. It's often too good a television set for the signal a station is putting out; one begins to realize how careless some stations are about color quality and the state of their film and tape stock. They are going to have to shape up.

The KV-2643R (such a romantic name) is the first Sony console to be marketed here, although the 21-inch table model was far too heavy to be considered portable. Sony introduced the set domestically just this month; already, says salesman Eric Brobeck at Erol's TV in Arlington, "it's the hottest single item we have," with more than 20 sold by that dealership alone and a waiting list forming for future shipments. Sony claims that the set not only has the biggest picture but "a viewing area 8 percent larger than conventional consoles."

That may be why I could repeatedly see the boom mike peeping in at the top of the frame throughout the recent ABC telecast of the film "Harry and Tonto."

A microcomputer adjusts the channels and the color when the set is installed. It's a very complicated set-up (hidden behind a flimsy little door) replete with flashing red lights and blinking lighted numbers, all explained in totally inscrutable instructions that come with the set. After a few nights of steady rereading, you get the gist of it, if not the hang, but a serviceman will have set it all up when he installs it, anyway.

You take The Force with you: your Remote Commander; and feeling a little like Obi-wan Kenobi, you retire to a couch, never to rise again.

There are disadvantages to the set, in addition to the invitation to atrophy involved in never having to get up to change channels. Like predecessors to this top-of-the-line Sony, it is equipped with something called a Lumisponder, which is supposed to adjust the brightness of the picture to the room light. The only effect I have ever perceived from pressing this button was that of a shadow falling over the picture, as if a partial eclipse had just popped in. In addition, homes equipped for cable TV will find the channel browsing feature of the remote control useless, since cable brings with it a new channel selector of its own.

Also, the set costs just over a thousand bucks. But then, considering all the money you won't be spending on gas because the oil companies will claim there isn't any, $1,000 is a small investment to make in the prevention of cabin fever.

Oh, there've been many Sony TV sets in my life - the KV-1733R, the KV-2141R...such memories! Though I've never had even a twinkle of trouble with any of them, and though Sonys come back to the shop "two or three times less often" than other brands, according to salesman Brobeck, it should be noted that when they do come back, they are harder and more expensive to fix.

There's a conceptual problem with Sonys, too, a sort of philosophical quirk which doesn't really impede day-to-day viewing pleasure but occasionally becomes a drawback. There isn't much latitude in the adjustment of color. It pretty much has to be standard normal almost perfect; you can't play around, the way you can with some color sets, and improve dull programs by turning them into electron art. The brightness spectrum is also limited; the screen cannot be made completely dark.

Sonys rob one of a certain creative initiative, but they compensate with an almost sinister stab at infallibility. "I think everybody who works here owns a Sony," says Brobeck, though the store stocks several other brands. It's also hard not to have noticed that even in the highest executive suites of NBC, which is owned by RCA, a maker of television sets, one can find tell-tale Sonys prominently installed.

At Compact Video in Burbank, Calif., where they mix and edit hundreds of network videotape TV shows, Sony monitors are de rigeur.

The Sony dearest to my heart is the first one I ever owned, a little 7-inch color portable that sentimentality prevents me from selling. For awhile I was making the foolish mistake of trying to live in Georgetown, that over-rated watering hole for teen-age suburban drunks, and a thief broke into my apartment one day and attempted to make off with the set. He had to drop it on the back porch as cops approached, but the little beauty still performed gallantly when plugged back in again.

That was after I got it back from the cops, however, who took my picture with it for their files and placed upoin it a tag marked "Evidence," which remained there for several years. I remember sitting in the police station for an hour while I waited for one of Washington's cabs, with the brave little Sony sitting on my lap. To think I had almost lost her forever to some callous rapscallion.

To this day, just for a charge, I'll watch an occasional program on the small Sony because no matter how good the larger screens are, they can never quite match the concentration and brilliance of color you get from the little ones.

Mitsuru Okhi, a spokesman for the Sony Corp. in New York, says the 26-inch Sony will remain the largest available until a 32-inch size, already in industrial use, is turned into a home model. It won't happen this year, Okhi notes.

He also says Sony has another new toy, an improved Betamax video cassette recorder, due for release in mid-August. The SL-5400 will have a 4 1/2-hour recording capability and, more spectacularly, boast a new feature called BetaScan "for rapid search in forward or reverse." It means one can actually see the picture moving in fast forward or fast reverse modes, so that finding a certain part of a certain tape will be made much easier. Not even expensive professional machines have this feature. You can also freeze frames on playback of tapes, another rarity among VCR's.

And it will have remote control and a three-day timer-programmer and "14-position push-button Express Tuning" like the big old KV-2643R.

If companies like Sony kept coming up with these new delights, and they will, we'll all have to knock out walls and enlarge rooms to make space for the hardware of the '80s. perhaps we can convert the garage to a video room after we sell the car.

Now, if only there something on television worth watching. If only there were something worth recording. One small step for man, one giant snooze for mankind.The technology is willing but the artistes are out to lunch. Helas, maybe someday they'll catch up and all this technology can be used to some grand purpose. Even now it can be used to some purpose, of course. It can be used to make the viewing of old movies on Sunday afternoon even more pleasurable than it has already been.

For the technophrenic, the new Sony television set is also balm and sustenance because here, finally, in a time of Three Mile Islands and DC-10s and conspiring computers and wayward elevators and all manner of vicious faulty gadgetry, is A MACHINE THAT WORKS. With the KV-2643R, more at last is more. CAPTION: Illustration, no caption, by Juanita Mondello for The Washington Post; Picture, no caption,