Kodak Achieve CTP Output White Line Repair Case – TH5 Laser Head LVD Light Valve Fault Analysis

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Kodak Achieve CTP Output White Line Repair Case – TH5 Laser Head LVD Light Valve Fault Analysis

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Problem Summary

In daily repair of Kodak Achieve CTP, a fixed white line on the plate is a typical but complex fault.

Recently we received a Kodak Achieve CTP unit. The customer reported that the device had been running stably, but lately a clear white line appeared on output plates at a fixed position, affecting normal production.

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Field Symptoms

Tests on site revealed:

  • White line position was fixed
  • Appeared at the same location on multiple outputs
  • Remained after changing plates and recalibrating
  • Software and RIP data were normal

Based on years of repair experience, such faults typically require investigation in the following areas:

  • Laser head
  • LVD light valve (Liquid Crystal Light Valve)
  • Optical path contamination or damage
  • Abnormal laser power
  • Control board and drive circuit

Error Meaning

Fixed-position white lines indicate the fault is likely within the exposure system rather than random noise or data errors. The LVD light valve modulates each laser beam; failure of one channel leads to consistent underexposure at that scan position.

Diagnostic Path

Given the symptoms, initial suspicion pointed to the LVD light valve inside the TH5 laser head.

To avoid misdiagnosis, we performed a swap test.

We replaced the suspect TH5 laser head with a known good unit.

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Repair Action

After swapping the TH5 laser head, we output a test plate again.

Final Result

Results:

  • White line completely disappeared
  • Output returned to normal
  • Flat tints and image quality fully restored

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Thus, the fault was confirmed to originate from the LVD light valve module inside the original TH5 laser head.

Engineering Lesson

The LVD is a critical component in Kodak TH series laser heads. It controls the transmittance of each laser beam to ensure uniform exposure across the scan line.

When one channel of the LVD malfunctions, common symptoms include:

  • Fixed white line
  • Fixed thin line
  • Uneven flat tint density
  • Light balance failure
  • Calibration failure

It should be noted that not all white line faults are caused by LVD. A complete diagnostic flow must include:

  • CRB beam check
  • Laser power test
  • LVD functional test
  • Optical path inspection
  • CCD spot analysis
  • Output verification

Only a thorough investigation can pinpoint the root cause.

Related Services

Shanghai DTP TECH specializes in CTP equipment repair and technical support for Kodak, Screen, Heidelberg, and others. We offer:

  • TH series laser head repair (TH1–TH7)
  • LVD light valve testing and repair
  • Laser optical path calibration
  • CRB/CCD beam analysis
  • Remote CTP fault diagnosis

If your Kodak CTP shows white lines, exposure anomalies, light balance failures, or laser head issues, please contact us. We help quickly identify problems, reduce downtime, and improve equipment stability.

Shanghai DTP TECH CO., LTD.

Professional CTP repair | Laser head service | Parts supply | Remote technical support

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Is your Kodak CTP experiencing white lines or exposure issues? Let us help you diagnose and resolve the fault efficiently.

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