A Frequent Visitor Okuma MSM Unit

03.04.2025 by Viktor Siebert

A Frequent Visitor Okuma MSM Unit

A frequent visitor to our repair shop is the Okuma Unit Type MSM E0241-680-014B.

This unit is crucial for the smooth operation of all drive components in Okuma machines (e.g., Okuma MX-45V or MX-55V with control OSP-U100M/OSP-10M). It controls and monitors the machine movements and functions, thus serving as a critical interface.

Caution When Buying Used Devices

Currently, new units of this type are no longer available on the market; you can only buy them second-hand, which we strongly advise against. We ourselves have purchased several units to keep as exchange units for our customers. However, all units we acquired turned out to be already damaged. Our customers have confirmed this as well. It appears defective units are replaced and subsequently resold on the open market.

Typical Faults and Symptoms

Here’s what typically happens: Most faults are intermittent. Units may function flawlessly for days or even weeks but eventually fail due to operating temperature, humidity, vibrations, and other factors. Symptoms vary widely; sometimes an axis fails, and other times a total-failure alarm appears on the display, rendering the entire machine non-operational. Determining the exact cause is incredibly difficult. Usually, replacing the unit resolves the issue temporarily. Unfortunately, this isn’t always the case, especially with units sourced from the second-hand market or Asian suppliers, often falsely advertised as “new.” Nearly all units have hidden defects and eventually display similar failure symptoms again.

A Customer’s Troublesome Experience

This is exactly what happened to one of our customers. After nearly losing his patience, he received a tip that the MSM unit might be at fault. Purchasing directly from Okuma was too expensive and risky—Okuma wouldn’t accept returns if the unit was installed by the customer himself. Only units installed by their technicians could be returned, but at a loss. He decided to buy a used unit from one of many spare-parts suppliers, who assured reliable function and appeared knowledgeable.

Harsh Reality After the Purchase

The unit arrived quickly, and the customer installed it. However, after just two days, there was another shutdown. The unit reacted to vibrations. When contacting the supplier, our customer discovered the unit had merely been sourced and that the supplier had no technical understanding. The supplier promised to clarify with their source. Two days later, the customer was advised to inspect all cables, connections, and plugs. Even after thorough checking by an electrician, nothing improved—the unit continued failing with every vibration.

Desperation and Empty Promises

Under some pressure, the customer returned the faulty unit and was promised a quick exchange. After two weeks, several phone calls, and emails, he received a supposedly “like-new” replacement. Upon installation, this unit immediately showed errors. The machine produced continuous error messages, and nothing functioned. The supplier was contacted again, this time more clueless than before. The situation escalated, promises were made, but ultimately the supplier vanished. The customer tried unsuccessfully for two more weeks to reach him, having already paid in full, left with a defective spare part, and no solution in sight.

Professional Repair as the Solution

Finally, on recommendation, the customer approached us. We received the defective unit bought from the supplier for repair, while his machine continued operating on the partially defective unit. We thoroughly examined the unit and confirmed its defects after installing it in our test machine.

With extensive experience in these units, we successfully repaired the device, clearly originating from the Asian market. It was by no means new, merely cosmetically refurbished. We were familiar with the specific faults and repaired them within three working days.

A Happy Customer and Sustainable Solution

About a week later, the customer happily reported that the refurbished unit had shown no errors since its installation. He immediately expressed interest in sending us the second unit as well. He was relieved to finally have a lasting solution. Although unlucky with the previous supplier, he ultimately saved money. Now he even has a fully functional spare unit, which will significantly reduce costs in future repairs—especially important as he operates more than 50 machining centers.

This story illustrates what is currently happening on the second-hand market and highlights the importance of consulting experts from the very beginning.