"Check your anode voltages again."
"All O.K."
"How about that aligning job?"
Barney fiddled with the alignment screws for minutes, but his original setting seemed to be valid.
"Back to normal," said Barney. "Rip out your cabling."
"Huh?"
"Sure. You did something. I don't know what. But rip it out and fan out the leads. There is something screwy in the supply lines. I've been tied up on that one before; this thing looks like electronics, as we agree, and I've had occasion to remember coupling troubles."
"All right," said Jim, and he reluctantly ripped out his lock-stitching. He fanned the leads and they tried it again.
Obediently the light dimmed and the wallpaper burned.
"Here we go again," said Jim, killing the circuits and reaching for a small rug to smother the fire. "No wonder the Martians had this thing out in the middle of the desert. D'ye suppose that they were trying to find out how it works, too?"