Common Ultrasound Faults and Repair Cases

Color ultrasound equipment is an extremely advanced diagnostic system that utilizes a large number of scientific technologies, such as nuclear magnetic resonance technology, Pureware pure wave probe technology, and tissue difference correction technology; a general color ultrasound system includes the following parts: probe, front-end signal acquisition part, power module control part, signal image processing part, and output display part.

Below, we share some common color ultrasound fault cases and repair procedures:

1. The most frequent failures occur in the power circuit

The power circuit is mainly of two types: series and switching. It is basically composed of oscillation, transformation, rectification, filtering, and voltage regulation. Its function is to convert alternating current into stable alternating and direct current voltage to provide energy for the machine. The power circuit has a large working current and generates a large amount of heat, so the failure rate is high. Components such as rectifier bridges and voltage regulators may be damaged when the load is too heavy (i.e., the current is too large), the grid voltage is too high, and the temperature is too high (e.g., poor heat dissipation). Therefore, an AC voltage regulator should be installed to stabilize the power voltage; air conditioners should be installed to lower the indoor temperature, and the dust inside the machine should be cleaned regularly. These measures can effectively reduce the possibility of damage to the power supply and greatly reduce the machine's failure rate.

The repair of the power circuit mainly involves checking and repairing these components. Understanding the principle and function of the power circuit means thatregardlessof whether it is an imported machine or a domestically produced machine, the repair ideas and methods are the same. In fact, the ideas are very similar to those of repairing other electrical appliances, such as televisions and computers.Many damaged imported machines can achieve ideal results using domestic components instead.

2. Repairing the display part is similar to repairing a computer

The display part of the ultrasound is actually a computer, a dedicated one: it has a host, a monitor, and a photo monitor.

The monitor consists of several major parts: video amplification, scanning, and display. It displays the ultrasound image from the host with high resolution. Through practice, we have found that monitor failures often occur in the scanning part, with the highest failure rate in the line scan. Similar to the power supply, the line scan operates at high voltage and high current, consuming more than half of the monitor's power. During normal operation, there are a series of heat-generating components, such as: line output tube, line output transformer, and line correction coil. When the heat dissipation is poor, these components can be damaged due to overheating or cause the circuit board to crack.

We have repaired several EUB200 ultrasound machines. The host worked normally, but the monitor had no light, only a vertical bright line. After repeated checks, it was found that the line correction coil of the line scan was unsoldered due to high heat. After resoldering, the fault was eliminated. This shows that high temperature can cause failures in many parts of the ultrasound. Therefore, ventilation and cooling are very important for B. This can prevent problems before they occur and better ensure the normal operation of the machine. It can be seen that the repair of this part is very similar to the repair of a computer.

3. Keyboard failure

In fact, the ultrasound keyboard is basically the same as a computer keyboard: the repair ideas and methods are also basically the same as repairing a computer keyboard. It is also composed of various function keys and alphanumeric keys. It is the part of the ultrasound that is operated the most. Due to different manufacturers and models, the keyboards are slightly different, but they can be roughly divided into two types: one is composed of independent button switches; the other is an integrated touch-type key, generally speaking, the latter is a recent product. The most typical keyboard failure is poor contact. Most poor contact is caused by dust, contact oxidation, or damage to the conductive rubber in the touch switch, but the most common cause is dust.

For example: We repaired a Mindray ultrasound DC-N2S. The failure phenomenon was that the monitor displayed normally, but there was no echo image on the screen, and the keyboard control failed. Inspection of the host revealed a fault. After opening the keyboard, it was found that there was too much dust inside the keyboard. After careful cleaning, the machine returned to normal. This example fully illustrates that dust prevention is very important for ultrasound. The standard conditions for placing ultrasound are in a room with air conditioning,dryand well-ventilated and clean. Even so, the ultrasound should be regularly cleaned and maintained (at least once or twice a year). This will greatly reduce the failure of the ultrasound keyboard and other parts.

4. Color ultrasound probe

The ultrasound probe is a unique component of the ultrasound, and its failures have unique characteristics, but they are not complicated.

Commonly used ultrasound probes include linear array probes and mechanical sector scan probes. Mechanical sector scan probes have more failures. Common failures include air bubbles in the sector scan probe. The solution is to vent and fill with oil. The treatment method is described in relevant books, and it will not be repeated here. Another common failure is that the sector scan probe does not rotate. This is usually due to damage to the probe's drive motor. In this case, the treatment is more troublesome and requires sawing open the probe.

5. Failures caused by machine vibration

Medical ultrasound is a very complex electronic instrument, with many circuit boards, plug-ins, and wiring. When subjected to large vibrations, these plug-ins may become loose, causing poor contact, resulting in the entire machine or part of the machine's functions not working properly. Once, we repaired an All)-DA-SSD-630. composite machine, the machine's continuous Doppler did not work, but other functions were normal. After checking the machine, no faults were found. After cleaning the plug-ins, the machine worked normally. This example tells us that we must minimize vibration when moving the ultrasound, and the locking switch of the ultrasound's wheels must always be locked to prevent the machine from sliding and colliding with other objects. In summary, we can see that ultrasound failures are varied and sometimes confusing, but ultrasound repair work also has its technicality, scientificity, and regularity. As long as we carefully analyze and thoroughly find the cause, even complex faults can be eliminated. However, if there is a slight oversight, it will lead to more detours and even cause more losses.

Repair Summary

Repairing such sophisticated ultrasound equipment should never be attempted blindly. The following precautions must be strictly observed during maintenance:

1. Ultrasound machines have complex structures and are difficult to repair. Therefore, disassembly must be approached cautiously and methodically. Avoid brute force. Maintain detailed records and markings to prevent incorrect reassembly.

2. Repair personnel must carefully review the circuit diagrams and block diagrams. Analyze the circuit based on the fault symptoms to determine the fault range. Never allow unqualified individuals to disassemble or repair the equipment, as this may worsen the problem.

3. The integrated circuits in ultrasound machines are mostly composed of CMOS circuits. These circuits are easily damaged by static electricity from the human body or the machine casing. Therefore, during maintenance, instruments and tools must be reliably grounded, especially the outer casing of the soldering iron.

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