"A number doesn't have to be impossible to be wrong," Marcus answered. "You could be trying to repair a fan that is listening to bad information." He stopped there, conscious that a confident guess was not the same as a diagnosis. "You'd need to check the sensor against the manufacturer's specifications."
Gerald approved an isolated measurement after the system had been placed in a safe service state. Luis performed it with the proper test equipment while Peter consulted the manufacturer's data sheet. When the values appeared on the laptop, Peter moved closer. "That's outside its expected resistance range," he said, reading the figures again.
Natalie had been silent for the last several minutes. "Does that mean we have the answer?" she asked. Marcus stood and wiped the knees of his uniform with one palm. "It means you have something testable. A replacement sensor should tell you whether that's the reason for the shutdown."
Peter looked at Gerald. "There's a spare in the lower maintenance inventory," he said. Gerald checked the parts list, then sent Luis down to retrieve it. Natalie glanced at the clock above the conference-room door. It was 12:38 a.m., and the first guests would arrive in fewer than eight hours.
While they waited, Peter returned to the laptop and began reviewing the startup log from the beginning. He was quieter now, but not resentful. Marcus had seen people defend a wrong diagnosis long after they knew it was wrong, and Peter was at least willing to keep looking. "I spent two hours on the relay circuit," Peter said after a while. "I wanted the last noise to be the cause."
"I probably would have done the same if I'd been looking at it all night," Marcus replied. "When something keeps making the same noise, it's hard not to decide what it means." Peter glanced at him, surprised by the absence of triumph. Marcus understood that repair work was full of false certainty and that a person who never missed a fault was usually a person who never admitted having missed one.
Natalie moved to the long conference table and set down her notebook. "You said you used to repair equipment," she told Marcus. He nodded. "What sort?" "Mostly refrigeration, commercial appliances, and some building controls. Nothing quite as polished as this cabinet."
"Why did you stop?" Her question was direct, but her expression made clear that he did not have to answer. Marcus looked at the cloth resting on his cleaning cart outside. "My daughter's mother left when Emma was small. The repair shop had good weeks, but there were nights I'd get a call at nine and still be on a job when the sun came up. I needed hours I could plan around."
Natalie glanced at the time. "And the cleaning work gives you those hours?" "Ten until six," he said.
"It's not easy, but it's predictable. I can get home, see Emma off to school, sleep while she's in class, and be there when she needs me later. Mrs. Alvarez watches her while I work nights."