Chapter 175: Midnight Inspection

At one in the morning, the workshop’s incandescent lights switched to energy-saving mode on schedule, dimming by a notch, but the thunder of the stamping press did not weaken in the slightest. Lin Chen nudged the plastic stool half a meter closer to the distribution cabinet, lifted his left foot onto a stack of insulating mats, and held the multimeter steady in his right hand as he touched the probe to the grounding bus connection.

The 3.2 ohms he had measured that afternoon had been under no-load conditions. Now the press was running at full load, the motor starting and stopping constantly, and current moved through the grounding line like an underground river. The moment the probe made contact, the reading jumped: 4.1 ohms. Too high. The cracked insulation was only the surface problem. The real issue was the contact surface between the grounding electrode and the copper bus. Long-term moisture and electrolytic corrosion had made the contact resistance climb exponentially under load. If he did not deal with it, tonight’s voltage fluctuations would punch straight through the terminal’s ADC sampling module.

He set down the multimeter and dug through his tool bag for fine sandpaper, conductive paste, and an insulated wrench. He moved slowly, bracing himself with his left hand while his right carefully polished away the oxidized layer. Verdigris mixed with rust flaked down onto the oil-stained concrete and was soon soaked dark brown by seeping cutting fluid. Once the metal shone again, he squeezed on conductive paste and tightened the bolt with the wrench. The torque could not be too high, or the copper bus would deform; it could not be too low, or vibration would loosen it again. He tightened it by feel to three and a half turns and stopped. His knuckles had gone white from the strain, and the veins on the back of his hand stood out faintly in the pallid light.

The terminal log was still scrolling.

[INFO] Ground potential stabilized.

He measured the resistance again: 2.8 ohms. Within spec.

The only other person in the workshop was Old Li, one of the press operators, dozing with his hard hat crooked over his forehead, breathing heavily. Lin Chen did not wake him. He only turned the terminal’s cooling fan down by one setting. The noise dropped, but the temperature would rise by two degrees. In his notebook he wrote:

1:40 a.m. Ground impedance optimized to 2.8Ω. Fan speed reduced; enclosure temperature expected to rise. Inspect heat sink once every hour.

The pen scratched across the page. He was used to writing down every variable. Code could crash. Machines could age. But the record on paper did not lie.

He leaned back in his chair and pulled half a pack of compressed biscuits from his pocket. The plastic wrapper crackled in the stillness. He broke off a piece and swallowed it dry. The rough crumbs scraped painfully at his throat. He unscrewed a bottle of mineral water and took only a small sip. The water was cold, sliding down his esophagus and setting off a faint spasm in his stomach. He could not eat too much. Too much food would send blood to his stomach and dull his mind. He needed to stay awake until nine in the morning.

His phone screen lit up. A bank text message:

Account balance: 124.70 yuan.

Old Zhao still had not settled the remainder of the payment. The factory’s advance, after medicine and consumables, was nearly gone. His younger brother’s sodium valproate for next month was still four hundred yuan short, and his mother’s amlodipine would have to be cut in half for a while. He turned the screen off and laid the phone face down on the desk. The numbers were only a reference. The real ledger was inside the terminal. Seventy-two hours. Ninety-nine point five percent integrity. Miss it by one-tenth of a percent, and the penalty in the side-bet agreement would fall like a cleaver. He could not afford to lose, and he had no right to.

At three in the morning, the press entered a high-frequency stamping cycle: forty-two strokes a minute. The vibration traveled through the anchor bolts into the terminal bracket, and the legs of the plastic stool trembled slightly. Lin Chen stared at the screen as dense warnings began to appear in the log:

[WARN] Vibration threshold exceeded.

The moving-average filter had already been pushed to its limit. Relax it any further and the effective signal would be smoothed away with the noise. He opened the low-level driver and added a dynamic weighting algorithm to the data-validation layer. When vibration increased, it reduced the weight of the high-frequency samples; when things stabilized, it restored full acquisition. Code was not a mathematical formula. It was a compromise made on a workshop floor. He had to teach the system how to pick out signal from noise.

At four-thirty, the sky began to turn gray-white. A weak light came in through the window at the end of the corridor. Lin Chen stood up. The moment his left foot touched the ground, a sharp pain shot from his ankle to his knee. He clenched his teeth and braced himself against the wall as he made his way back to the terminal. Uptime: thirty-one hours. Data integrity: 99.89%. He opened his mistake notebook and added one last line:

High-frequency vibration causes sampling jitter. Countermeasure: dynamic weighted filtering deployed. On the hardware side, replace vibration-damping pads during the next shutdown.

He opened the data export script. The terminal packaged the past thirty hours of raw data into a CSV file and appended an MD5 checksum. The progress bar in the lower-right corner crept forward slowly. Ten percent. Thirty. Seventy. The fan’s hum sounded especially clear in the empty workshop. Taking advantage of the pause, he wiped his face with a wet tissue and pulled the zipper of his grease-stained jacket all the way up. Before nine, he had to print the initial data, the pressure-test curves, and the hardware retrofit checklist, then bind them into a report. The expert team’s calibration instrument would not lie, and neither would the original ledgers. Every line of the log had to match up.

The progress bar reached one hundred percent.

[INFO] Export complete. File size: 48.2MB. Checksum: OK.

He plugged in a USB drive and copied the files over. In the corner, the printer gave off a heavy swallowing sound as page after page of A4 paper stacked up, still warm with static. He checked each page, signed it, stamped it. His movements were mechanical, but meticulous. The edge of the paper sliced open his fingertip and drew a bead of blood. He pressed a tissue to it and did not stop.

At 7:20, the factory broadcast system suddenly burst into harsh static. A second later, the main breaker in the distribution room snapped open with a click. The entire workshop went dark at once, except for the eerie green glow of the terminal’s backup battery indicator. The press motor gave off a low inertial hum before slowly winding down.

Lin Chen’s heart skipped a beat. This was not a fault trip. It was a scheduled grid load test. The factory ran a full blackout drill every six months, but notice usually came three days in advance. This time there had been none.

The terminal screen automatically switched to cache mode.

[INFO] Power loss detected. Switching to battery backup.

He immediately pulled up the low-level log. Voltage had plunged from 220V to 0V. The watchdog had triggered normally. SD card reads and writes were intact. But the last line in the log was something he had never seen before:

[WARN] Phase shift detected on L2 line. Sync error: 12ms.

His brows drew together. A phase shift on the L2 line? The factory’s three-phase power was balanced unless… He grabbed the multimeter and tested the CNC machine outlet beside him. The voltage needle quivered slightly. He understood at once. At the instant of the blackout, the CNC cluster in the next workshop had switched to UPS bypass and injected harmonics back into the grid. The terminal’s power module had survived the outage, but the phase shift would cause microsecond-scale cumulative error in the internal clock crystal.

The expert team’s calibration instrument worked at millisecond precision. A synchronization error of twelve milliseconds would be marked in the raw ledger as “data drift.” If he could not explain it, the integrity score would be cut straight below ninety-eight percent.

He glanced at the wall clock. 7:25. The expert team would arrive in one hour and thirty-five minutes.

Lin Chen sat back down on the plastic stool, pulled out the USB drive, and plugged it back into his laptop. He opened a hex editor and read the terminal’s low-level clock registers directly. Code cascaded down the screen like a waterfall. He had to correct the clock offset manually without rebooting the system and produce a phase-compensation note. There was no time to write a full patch. Only a hotfix would do.

He typed the first command. His fingertips were cold, but the rhythm of his keystrokes was steady. The workshop lay in total silence except for the clicking of the keyboard and the faint hiss of current from the backup battery. Inside his shoe, his left foot had swollen hot and tight, the inflammation climbing up through the muscles of his lower leg, but he could no longer feel it. All of his senses had narrowed to the screen and his hands. He compared crystal-frequency tables line by line, calculated the compensation value for the offset, and modified the register mapping. He could not get even a single byte wrong. One mistake, and the terminal could brick itself on the spot.

7:40. The compensation script finished compiling. He drew a deep breath and pressed Enter.

The terminal screen flickered. The log began to scroll again.

[INFO] Clock sync adjusted. Phase error compensated.

He let out a long breath and leaned back in his chair. Outside, daylight had fully broken, and the footsteps of the morning shift echoed down the corridor. Leather shoes clicked over terrazzo, accompanied by Old Chen’s lowered voice urging someone on:

"Lin Chen, did you export the data? The provincial bureau’s car has already come through the factory gate."

Lin Chen closed his laptop and shoved the bound report into the shockproof case. He got to his feet, keeping his left foot off the ground, his weight on the right, and slowly headed for the door.

At the far end of the corridor, the door to the meeting room was pushed open. Several figures in dark jackets were bent over, checking the ledgers. One of them looked up, his gaze passing over the crowd and settling on the shockproof case in Lin Chen’s hand.

"Did you bring the terminal’s original clock logs?" the man asked.

Lin Chen tightened his grip on the handle, the metal edge cold in his hand. He nodded and stepped into the meeting room.

The real comparison was only beginning.