Three Cases of GE Logiq P6 Ultrasound Diagnostic Equipment Troubleshooting and Repair

LogiqP6 is a highly integrated device. The host part mainly consists of a motherboard, probe connection board, transmit-receive board (DTRX64), Doppler board, integrated PC, DC power supply (APSII), rear output board device power box (Transbox), etc.

                                            Figure 1 Logiq structure diagram

The working principle of LogiqP6 is that the DC power supply provides high voltage to the transmit-receive board. DTRX64 connects to and controls the probe to transmit ultrasonic waves through the probe connection board. The echo after the ultrasonic wave scans the organ or lesion is converted into an electrical signal by the probe and received by DTRX64. Finally, through the processing of the integrated PC, an ultrasonic image is formed on the display.

Malfunction phenomenon 

The device powers on normally, but interference occurs in the high-frequency probe, while other probes are used normally. 

Malfunction analysis 

Image interference is a common fault in ultrasound equipment. To determine the source of interference in ultrasound equipment, three aspects should be considered: ① Electromagnetic interference from outside the equipment; ② Interference generated by the probe; ③ Interference generated from inside the equipment. High-frequency probes produce higher-frequency sound waves and higher conversion voltages than other probes, making them more prone to interference. 

Troubleshooting

First, rule out electromagnetic interference from outside the equipment. Move the equipment to the DR room with the best power environment and shielding, which can effectively shield most external interference. The interference of the high-frequency probe still exists after starting the equipment, ruling out electromagnetic interference from outside the equipment. 

Then check for interference generated by the probe itself. Check the probe for any damage or cracks; the probe's own shielding is intact. After changing the probe interface, the fault persists. Take the probe off and test it on other applicable equipment; the image is normal, ruling out probe failure. 

Finally, check for interference generated inside the equipment. Enter the system service page, let the equipment perform self-test, and try to find the cause through the device's own program; all tests can pass. Because DTRX64 is the main component for receiving sound waves to form images, after communicating with the factory engineers, it is suspected that there may be a problem with the DTRX64 board, so a test is performed with the DTRX64 board. After replacing two DTRX64 boards, the interference problem with the high-frequency probe still occurs. 

Through analysis of the equipment structure, after the image forms a signal at the front end, it is processed by the backend SYSCONML board. It is suspected that there is a problem with the SYSCONML board, so it is decided to test the SYSCONML board again. Remove the SOM board (Figure 2) from the original equipment and install it on the newly replaced SYSCONML board. Note that when replacing the SYSCONML board, the ASIRROM (Figure 2) on the original SYSCONML board of the machine must be removed and installed on the newly replaced SYSCONML board, because ASIRROM stores the original machine's hardware basic information, parameter adjustment settings, and other important information. When installing the chip, be sure to pay attention to the direction of the ASIRROM (Figure 3); if it is installed backward, it will also cause the equipment to fail to start. After installing the SYSCONML board, the equipment starts, and the high-frequency probe does not show any interference, and the fault is resolved.

                    Figure 2 Location of ASIRROM/SOM on the SYSCONML board

                                              Figure 3 ASIRROM installation direction

Ultrasound equipment image interference is checked from three perspectives: external electromagnetic interference, probe itself failure, and equipment internal interference. External electromagnetic interference and probe itself failure are more common, and the board card with transmit-receive function is the most common internal interference, but the possibility of interference caused by other board cards cannot be ruled out. This fault is a computer part fault. Many computer part cards have corresponding storage components; care should be taken not to forget to install them when replacing them.

Malfunction phenomenon 

After the equipment is powered on, there are two black strip echoes missing in the near-field middle-right of the scanning area (Figures 4-5).

                                                            Figure 4 High-frequency probe image

                                                        Figure 5 Cardiac Probe Image

Fault Analysis 

There are two main reasons for image loss: ① Probe failure, including probe crystal failure, probe cable damage and breakage, and probe interface contact failure; ② Failure of the equipment's transmission and reception part. If the failure image is due to this part, it should be caused by the failure of one of the two DTRX64II boards. 

Troubleshooting 

First, check that the probe has no external damage or cracks, and that the probe connector and interface have no broken or stuck pins. Since this problem occurs with two probes of different models, the probability of probe crystal failure is relatively low. Remove both probes and test them on other applicable equipment. The image is normal, ruling out probe failure.

 Open the front end of the device as shown in Figure 3. Both DRTX64II boards are marked with "1". Check and compare the version number and spare part number of both boards, which are the same. Swap the two DRTX64II boards, swapping the left and right boards. After powering on, it is found that the two originally right-side black missing bars are changed to the left side. Therefore, the right DTX board is suspected to be faulty. Contact the manufacturer to order a new DRTX64II board, replace the new board to the right side, the probe image is restored to normal, and the fault is eliminated. 

Ultrasound image loss mainly includes the probe and the transmission and reception part. This fault is due to the failure of the DTRX64II transmission and reception board. Understanding the imaging principle of ultrasound equipment, the same board can be used for testing, which can quickly determine the fault point and quickly solve the equipment fault. Probe failure is also a major cause of image loss and needs to be investigated.

Malfunction phenomenon 

The device cannot start, and there is no response when the start button is pressed. 

Fault Analysis 

When the device starts normally, the monitor and control panel light up, accompanied by the sound of the fan rotating, and the indicator lights on each board light up. However, this device does not have any normal start-up response. Based on the fault phenomenon, it is judged that the device's power supply Transbox may not be supplying power normally. 

Troubleshooting 

First, check the UPS power supply of the equipment. The output voltage of the power supply is normal, eliminating the power supply problem. Then check the equipment's Transbox power supply (Figure 6). Other components and boards of the equipment are powered by the Transbox power supply. After removing the Transbox power supply for inspection, it is found that the two fuses on the ACPC board shown in Figure 7 are blown. After replacing the fuses of the same size, start the equipment. The fan stops as soon as it starts to turn, and the indicator lights on other boards flash and go out. After checking the ACPC board fuses again, it is found that they are blown again. This indicates that there is a short circuit elsewhere in the equipment, which causes the fuses to blow. The component connected to the next phase of the Transbox power supply line is the APSII power supply board. Remove the ASPII power supply board from the equipment, open the power supply housing, and carefully check the transistor next to the heatsink and find obvious black marks. Replace the transistor of the same model, replace the ACPC board fuses again, reconnect the circuit, and restart the equipment. The equipment starts and runs normally, and the fuses on the ACPC board are not blown. The fault is eliminated.

                                                    Figure 6 Transbox Power Supply

                                                    Figure 7 Fuse Location on ACPC Board

The power supply is an important component of the ultrasound equipment. This fault is caused by the failure of the transistor in the APSII DC power supply, causing the Transbox power supply box to blow the fuse. In most cases, blown fuses are caused by other components. When troubleshooting blown fuses, multiple factors need to be considered. Familiarity with the power-on process and structural principle of ultrasound equipment is necessary for successful troubleshooting.