VPL servo motor FR-D740-7.5K-CHT is safe and reliable

VPL servo motor FR-D740-7.5K-CHT is safe and reliable

Repair Techniques for Industrial Circuit Boards

Cannot overly rely on online testers

1. Functional testing cannot replace parameter testing

2. Functional testing can only test the cutoff region, amplification region, and saturation region of the device, but cannot understand the high or low operating frequency and speed at this time.

For digital chips, only the output changes of high and low levels are known, but the speed of its rising and falling edges cannot be detected.

For analog chips, they handle the simulated changes. The distribution of circuit components and the impact of different signal solutions are complex and intricate. With current online testing technology, it is impossible to solve the problem of simulating chip online testing. So, the results of this functional test are only for reference.

5. Most online testing discussions will give a "test pass" or "test fail" after conducting functional tests on various chips on the circuit board. So why doesn't it provide whether there is a problem with the tested device? This is the weakness of this type of testing device. Because there are too many factors that can affect (interfere with) online testing. It is worth studying whether it is effective to take various measures before testing, such as disconnecting the crystal oscillator, removing the CPU and chips with programs, and adding isolated interrupt signals. At least, the current test results are sometimes unsatisfactory.

6. Readers who are familiar with online testers know that there is a saying. The chip that fails the online test does not necessarily have to be damaged; the chip that passes the test must not be damaged. Its explanation is that if the device is affected by online interference or anti-interference, the result may not pass, which is not difficult to understand. So, will damaged chips always result in 'fail' during testing? The answer is indeed uncertain. Both the author and colleagues have encountered situations where the chip is already damaged (to be precise, replacing the chip board would not work), but the test results have passed. Explain that this is due to the working principle of the tester itself (rear drive technology). Therefore, we cannot overly rely on the function of online testers (although advertised by various manufacturers), otherwise it will lead the work of repairing circuit boards astray.

VPL servo motor FR-D740-7.5K-CHT is safe and reliable

On March 20th, the 22nd CAIMRS and Digital Intelligence Forum was held in Nanjing. Through gongkong ® At the 24th Industrial Automation and Digitalization Annual Awards from 2025 to 2026, Mitsubishi Electric Automation was selected as one of the "Top 50 Automation+Digitalization Annual Rankings". With its revolutionary product FA Integrated Controller MELSEC MX Controller, it stood out from many participating products and won the "New Quality" Award for Sports Control and Transmission Products.

In the increasingly fierce competition of intelligent manufacturing, Mitsubishi Electric will continue to make efforts to drive industry evolution with technology, constantly break through technological boundaries, rely on various innovative products such as MELSEC MX controllers, deeply integrate artificial intelligence and digital twin technology, promote the continuous progress of industrial automation, and establish a new foundation for global intelligent manufacturing. <span style='font-family:system-ui, -apple-system, 'white-space:normal; background-color:#FFFFFF; '>