Kodak Magnus 800 Frequent Overcurrent? We Built a Real-Time Kollmorgen Servo Diagnostic System

On Kodak Magnus 800 CTP systems, Kollmorgen servo drives handle critical motion-control tasks.

The drives themselves have mature design and stable performance. But as equipment runtime increases, power-stage components, current sensing, power supplies, feedback circuits, and external mechanical loads can all gradually change.

One of the most common field issues is:

Over Current — servo drive overcurrent alarm.

Many repair technicians immediately suspect power module damage.

But after years of Kodak CTP repair work, we found that overcurrent is only the final expression. It does not necessarily mean the power module is bad.

The Same “Over Current” Code Can Hide Completely Different Faults

A Kollmorgen overcurrent alarm may involve the power output stage, current sampling, motor, cabling, encoder feedback, DC bus, or mechanical load.

For example:

• IGBT / IPM power module abnormality
• Current sensor or sampling circuit zero drift
• Three-phase output imbalance
• Motor winding or motor cable insulation abnormality
• Encoder feedback abnormality that destabilizes the control loop
• Motor stall or sudden mechanical load increase
• Abnormal DC bus
• Aging internal drive power supplies
• Faulty control parameters or feedback signals

All of these can eventually produce a similar Over Current alarm.

This is the most frustrating part of repairing older equipment:

An alarm code usually tells you the result, not the cause.

The Biggest Problem Is Not Repair — It Is Diagnosis

Traditional repair often follows this path:

Over current alarm → test power module → suspect drive board → replace parts → test on machine.

If the fault remains, replace more components.

The biggest weakness of this method is the amount of time spent on trial and error.

This is especially true for intermittent overcurrent, alarms that only appear after a period of runtime, alarms during acceleration, or alarms under a specific load. A multimeter and static measurements often cannot show what happened in the tens or even hundreds of milliseconds before the fault.

So we kept asking one question:

Can the real-time state of a Kollmorgen drive be made visible?

Now, that tool is complete.

DTP TECH Develops Real-Time Test and Observation Software for Kollmorgen Servo

For the Kollmorgen servo systems used in Kodak CTP, we developed dedicated real-time test and observation software for drive repair, maintenance, and fault analysis.

Its purpose is not simply to read an alarm code.

It continuously reads, records, and displays key internal drive data.

This means technicians no longer see only:

OVER CURRENT

They can also observe what the drive was doing before the alarm occurred.

From “Fault Code” to “Fault Process”

Take Over Current as an example:

• If current rises sharply while speed drops before the alarm, the focus should be on mechanical load, motor stall, and the control loop.
• If no significant load change exists but one phase current is abnormal, inspect the power output stage, current sensing, and motor circuit.
• If current feedback has an obvious offset while the motor is stopped, the investigation shifts to current sensors, sampling amplifiers, and related analog circuits.
• If the alarm is accompanied by abnormal bus voltage, power supply, or feedback signals, the analysis direction is completely different.

The same alarm code can point to completely different repair targets.

That is the real value of live data.

The Moment of Failure Can Be Recorded

Many servo faults last only a very short time.

The equipment may run normally for dozens of minutes, even hours, then suddenly alarm and stop.

When the technician arrives and restarts it:

It runs normally again.

This type of fault is the hardest to handle.

So our diagnostic approach is not limited to checking current values. The software continuously monitors drive state, records trend curves, and saves what changed before and after the fault.

This turns the old question:

“Why did it alarm just now?”

into:

“What happened to current, speed, position, and drive status just before the alarm?”

The repair meaning of these two questions is completely different.

An Alarm Code Is Not a Repair Conclusion

We emphasize this point:

Error Code ≠ Failure Component

An alarm code is only a protection result generated by the controller according to its detection logic.

True professional repair must continue along the chain:

Alarm → real-time data → abnormal variable → circuit/load → failed part

That is the complete fault chain.

The purpose of this real-time test software is to help repair technicians build that chain.

From “Replace Parts” to “Repair with Data”

Through extensive Kodak CTP and Kollmorgen drive repair practice, one thing has become clear:

Older equipment does not only need spare parts.

It needs faster, more reliable answers to the question: Where is the fault actually located?

Because of this, our Kollmorgen drive repair approach has gradually shifted from:

Alarm → guess → disassemble → replace part → test

to:

Alarm → data capture → waveform analysis → fault location → targeted repair → data verification

The biggest benefit is fewer misjudgments.

It also reduces the time spent on repeated disassembly, repeated repairs, and repeated on-machine testing for the same drive.

Fast, Accurate, Stable — What Old CTP Repair Really Needs

Many Kodak CTP systems have been running for more than ten years, and some much longer. Core components have entered the aging stage.

Future repairs cannot rely on experience alone.

Experience still matters, but it must be combined with data.

DTP TECH now applies this real-time test and observation method to Kollmorgen servo drive repair and maintenance.

Our goal is simple:

• Fast: Quickly obtain the true running state and shorten fault-diagnosis time.
• Accurate: Do not replace parts blindly based only on an alarm code. Use actual operating data to determine the fault direction.
• Stable: Use real-time data again to verify drive condition after repair, reducing repeated faults and rework.

Keeping Older CTP Equipment Running Reliably

Kodak Magnus series CTP systems are still running in large numbers at printing companies around the world.

Higher equipment age does not mean it no longer has repair value.

What is often missing is professional diagnostic tooling, repair methodology, and long-term technical experience specific to these systems.

From laser systems, control boards, and power supplies to servo drives and motion control systems, we have been working on the same goal:

Turn faults that once relied on experience and guesswork into data that can be measured, recorded, and analyzed.

For industrial equipment repair, this may be more valuable than simply replacing a new part.

This software is suitable for all Kollmorgen drives.

DTP TECH — Kodak CTP Equipment · Laser · Electronics · Servo Repair & Diagnostics

If you are dealing with an intermittent Kollmorgen overcurrent fault on a Kodak CTP, would you like to see what the drive data shows before the alarm?