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Сурелы Ыоуре Joking, Mr. Феынман: Adventures of a Curious Character :: Feynman Richard Phillips
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But when we got there I went over to the radio and turnedit on. Little noise? My God! No wonder the poor guy couldn’t stand it. The thing began to roar and wobble—WUH BUH BUH BUH BUH—A tremendous amount of noise. Then it quieted down and played correctly. So I started to think: “How can that happen?”
I start walking back and forth, thinking, and I realize that one way it can happen is that the tubes are heating up in the wrong order—that is, the amplifier’s all hot, the tubes are ready to go, and there’s nothing feeding in, or there’s some back circuit feeding in, or something wrong in the beginning part—the HF part—and therefore it’s making a lot of noise, picking up something. And when the RF circuit’s finally going, and the grid voltages are adjusted, everything’s all right.
So the guy says, “What are you doing? You come to fix the radio, but you’re only walking back and forth!”
I say, “I’m thinking!” Then I said to myself, “All right, take the tubes out, and reverse the order completely in the set.” (Many radio sets in those days used the same tubes in different places—212’s, I think they were, or 212-A’s.) So I changed the tubes around, stepped to the front of the radio, turned the thing on, and it’s as quiet as a lamb: it waits until it heats up, and then plays perfectly—no noise.
When a person has been negative to you, and then you do something like that, they’re usually a hundred percent the other way, kind of to compensate. He got me other jobs, and kept telling everybody what a tremendous genius I was, saying, “He fixes radios by thinking !” The whole idea of thinking, to fix a radio—a little boy stops and thinks, and figures out how to do it—he never thought that was possible.
Radio circuits were much easier to understand in those days because everything was out in the open. After you took the set apart (it was a big problem to find the right screws), you could see this was a resistor, that’s a condenser, here’s a this, there’s a that; they were all labeled. And if wax had been dripping from the condenser, it was too hot and you could tell that the condenser was burned out. If there was charcoal on one of the resistors you knew where the trouble was. Or, if you couldn’t tell what was the matter by looking at it, you’d test it with your voltmeter and see whether voltage was coming through. The sets were simple, the circuits were not complicated. The voltage on the grids was always about one and a half or two volts and the voltages on the plates were one hundred or two hundred, DC.
But when we got there I went over to the radio and turnedit on. Little noise? My God! No wonder the poor guy couldn’t stand it. The thing began to roar and wobble—WUH BUH BUH BUH BUH—A tremendous amount of noise. Then it quieted down and played correctly. So I started to think: “How can that happen?”
I start walking back and forth, thinking, and I realize that one way it can happen is that the tubes are heating up in the wrong order—that is, the amplifier’s all hot, the tubes are ready to go, and there’s nothing feeding in, or there’s some back circuit feeding in, or something wrong in the beginning part—the HF part—and therefore it’s making a lot of noise, picking up something. And when the RF circuit’s finally going, and the grid voltages are adjusted, everything’s all right.
So the guy says, “What are you doing? You come to fix the radio, but you’re only walking back and forth!”
I say, “I’m thinking!” Then I said to myself, “All right, take the tubes out, and reverse the order completely in the set.” (Many radio sets in those days used the same tubes in different places—212’s, I think they were, or 212-A’s.) So I changed the tubes around, stepped to the front of the radio, turned the thing on, and it’s as quiet as a lamb: it waits until it heats up, and then plays perfectly—no noise.
When a person has been negative to you, and then you do something like that, they’re usually a hundred percent the other way, kind of to compensate. He got me other jobs, and kept telling everybody what a tremendous genius I was, saying, “He fixes radios by thinking !” The whole idea of thinking, to fix a radio—a little boy stops and thinks, and figures out how to do it—he never thought that was possible.
Radio circuits were much easier to understand in those days because everything was out in the open. After you took the set apart (it was a big problem to find the right screws), you could see this was a resistor, that’s a condenser, here’s a this, there’s a that; they were all labeled. And if wax had been dripping from the condenser, it was too hot and you could tell that the condenser was burned out. If there was charcoal on one of the resistors you knew where the trouble was. Or, if you couldn’t tell what was the matter by looking at it, you’d test it with your voltmeter and see whether voltage was coming through. The sets were simple, the circuits were not complicated. The voltage on the grids was always about one and a half or two volts and the voltages on the plates were one hundred or two hundred, DC.