The atmosphere at the scene was so heavy it was almost palpable.

The massive gantry planer lay sprawled in the center of the workshop like a dying beast, surrounded by all the factory's technical elites—senior engineers with graying hair, veteran craftsmen with rough, calloused fingers, and workshop directors and factory leaders with furrowed brows. The air was thick with the smells of machine oil, sweat, and an invisible tension.

The argument had continued from afternoon into the evening, with several high-powered light bulbs hanging from the temporary power lines casting flickering shadows of anxiety on people's faces.

"...It's definitely a problem with the main drive gearbox!" Director Ma of the machine repair workshop, who was in charge of the maintenance of all the equipment in the factory, said in a hoarse voice, pointing to the planer body. "There were occasional strange noises before, but now it's completely broken down. It must be a problem with the gears or shafts inside!"

“Old Ma, you can’t say that.” The electrical engineer adjusted his glasses. “I checked the main motor and control system. The current is abnormal, and the circuit breaker has tripped. This is clearly an electrical protection circuit caused by a sudden load change. The root cause may be that the feed system is stuck, creating a huge instantaneous load on the main drive!”

"We just overhauled the feed system not long ago, and it's been running smoothly ever since! Why did it have to break down now of all times?"

So you mean there's a problem with my electrical inspection?

Several experienced mechanics offered their own assessments. Some suggested poor lubrication caused the spindle to seize, while others suspected a chain reaction triggered by a loss of precision in the bed guideways. Each had their own reasoning, and everyone offered their opinion based on their experience, yet none could convince the others, let alone pinpoint the exact cause of the fault. The chief engineer rubbed his temples, his face revealing undisguised exhaustion.

As the least senior member of the technical department, Liu Li had virtually no say in such situations. She stood quietly on the periphery of the crowd, not joining any of the arguments.

She didn't stare at the arguing faces, but focused all her attention on the silent machine tool.

Under the light, she scrutinized every inch of the machine tool like a detective investigating a crime scene. Near the operating side of the bed guideway, she noticed a small patch of oil stain that was slightly darker and covered a larger area than the rest, unlike a normal, uniform oil film formed by seepage. Without making a sound, she moved her feet, adjusted her angle, and, using the light's reflection, saw an extremely fine, almost brand-new, longitudinal scratch on the lead screw guard under the planer's crossbeam. Less than two centimeters long, it would be almost invisible without careful observation.

Her ears were also trying to distinguish and recall. When the equipment tried to start up earlier, the brief sound of its operation was complex and rapid—not a single, violent metallic clang, but a series of dull, very short "clunk...clunk..." sounds, as if some part was struggling to move step by step, followed by the dull hum of the main motor as if it were being choked when the load on it increased sharply, and finally the crisp "click" of the electrical protection activated.

Oil stains, scratches, intermittent clicking sounds, an overloaded motor...

These seemingly isolated details, like scattered puzzle pieces, spun and collided rapidly in her mind. She subconsciously applied the system failure analysis thinking she was familiar with in modern projects, while Master Wang Jianguo's teaching of "observation, listening, questioning, and palpation" echoed in her ears.

Does the unusual oil stain indicate a failure at a critical lubrication point? Does that fresh scratch mean there's undue interference in the moving parts? And that rhythmic "clunking" sound seems to clearly indicate a specific, periodically obstructed mechanical movement...

A bold hypothesis gradually took shape in her mind: the problem might not lie in the core components of the main drive system or the feed system themselves, but rather hidden at the junction of the two, in a precision device responsible for linkage, signal transmission, or interlocking. It was this tiny fault in the link that accumulated and propagated step by step, ultimately causing a systemic failure.

This judgment made her heart race slightly. She knew that proposing this unverified conjecture at this moment would undoubtedly be a challenge to all the senior experts. Her hand, which was in her work pants pocket, unconsciously tightened its grip on the small notebook containing her scattered observation notes.

The surrounding arguments continued to rage, but she seemed to be in the center of a silent vortex, her gaze calmly sweeping over the silent behemoth, waiting for the opportunity to break the deadlock.