Four Cases of Olympus 260 Endoscopy System Malfunction and Repair

An electronic endoscope is a medical electronic optical instrument integrating advanced technologies such as light, mechanics and electricity. It can be inserted into the body cavity and visceral cavity for direct observation, diagnosis and treatment. The electronic endoscope system consists of an endoscope and its peripheral equipment, including an image processing center, a cold light source, a monitor, an ultrasound processing center, an electrosurgical unit and a workstation, etc. This article introduces four cases of Olympus 260 endoscope system fault repair encountered by the author for reference by colleagues.

Fault 1
1.1 Fault Phenomenon

After the endoscope system is powered on, the image can be displayed, but the image is discolored, or green, or red, or blue.

1.2 Fault Analysis and Repair

(1) According to the imaging system flowchart (as shown in Figure 1), following the principle of from easy to difficult, first check whether the host and monitor YPbPrRGB settings are consistent, and investigate whether it is a phenomenon caused by damage to the electronic endoscope charge-coupled device (CCD). After replacing an endoscope that is normally used on other hosts and adjusting the CCD automatic white balance, the fault remains.

Figure 1 Imaging system flowchart

(2) Since the endoscope host in this hospital is placed on a boom, and the connection between the host and the monitor is through an RGB adapter cable, the adapter cable fault may cause image discoloration. Therefore, the host MONITOR port data cable is directly connected to the monitor. The fault remains. The RGB adapter cable problem is ruled out. The MONITOR data cable is replaced, and the fault remains.

(3) The cable connecting the CLV260 cold light source and the image processing center is re-plugged, and the image quality is not improved. To prevent cable failure, the cable used on other hosts is replaced, and the fault remains.

(4) After ruling out the possibility of external faults, the problem points directly to the host itself. At this time, careful observation shows that the light emitted from the end of the electronic endoscope is not a flickering white light, but a colored light, which further confirms the fault of the cold light source. After opening the cold light source housing and connecting the power supply, the machine is turned on. After hearing the "pop" discharge sound from the high-voltage discharge board inside the machine, the xenon lamp is lit, but the grating turntable rotates slower and slower until it stops. The light source device is a device that provides in-vivo illumination by transmitting light to the light guide bundle of the endoscope. Because the image generation of this series of endoscopes uses a sequential scanning method, as shown in Figure 2, the sequential imaging endoscope can form a color image through an RGB grating. In order to achieve a clear image, the three signals are added together, so the light source emitted by the xenon lamp must pass through a high-speed rotating RCB grating. The absence of any color will cause image discoloration. In order to prevent oxidation and loosening from causing unstable power supply to the motor on the grating, the power supply line end of the motor is re-plugged, and the voltage measurement is normal online, but the grating still stops rotating after a while. This equipment has been in use for 6 years, and the grating and circuit board are covered with dust. Considering that the rotating shaft may be stuck by dust, the host is de-dusted, especially the rotating shaft of the light shed motor. After powering on and turning on the machine, the grating rotates rapidly at this time, and the image is displayed normally after connecting the endoscope.

Figure 2 Sequential scanning method

Fault 2

2.1 Fault Phenomenon

The Olympus 260 endoscope system is used with the ERBE VIO electrosurgical workstation for endoscopic submucosal dissection. When the electrosurgical mode is used normally, the monitor shows a black screen when the coagulation mode is used.

2.2 Fault Analysis and Repair

The factors causing interference faults can be divided into two categories: equipment fault interference and external intrusion interference. Equipment fault interference refers to interference caused by equipment itself failure, that is, interference caused by internal factors of the system. This type of fault is mainly caused by the power supply, monitor, etc. in the system. External intrusion interference faults refer to image interference faults caused by external interference signals intruding into the video spectrum during video signal transmission.

First, check the grounding of the Olympus 260 endoscope system, ERBE VIO electrosurgical workstation, and boom, and the power grounding. After checking, it is found that the grounding is good, which rules out the interference caused by unbalanced ground potential. The endoscope host and high-frequency electrical equipment share power sockets. The ERBE VIO electrosurgical workstation, 260 image processing system, cold light source, monitor, and various connecting lines are replaced one by one using the substitution method to check the equipment fault cause and find the interference source. During this process, it was found that when the metal parts of the RGB video adapter touched each other, there would be a black screen phenomenon. After wrapping the parts with insulating tape to isolate them, the test found no black screen phenomenon.

After the monitor was used normally for a period of time, the same black screen phenomenon appeared again. The above troubleshooting scheme is repeated. To prevent internal breakage of the RGB adapter cable, a new adapter cable is replaced, but the black screen still appears, which indicates that a new interference source has appeared. At this time, the only thing that has not been replaced is the argon knife connecting cable. After careful observation of the connecting cable, it is found that the outer skin near the machine output end is damaged and internally broken. It breaks with a slight pull. After replacing a new connecting cable, the black screen phenomenon no longer appears.

Fault 3

3.1 Fault Phenomenon

The Olympus 260 endoscope system host can be used normally when connected to an ultrasound endoscope, but a black screen appears when connected to a colonoscope, with text but no image display. 3.2 Fault Analysis and Repair

Different models of endoscopes that are normally used on other machines are replaced, and the test finds that only when connected to an ultrasound endoscope can an image be displayed, while no image is displayed when connected to a colonoscope and gastroscope, which rules out the problem of the endoscope itself. The light guide part of the electronic endoscope is connected to the image processing center through a connecting cable. Considering that the electrical connectors inside the light guide parts of the ultrasound endoscope and gastrointestinal endoscope are different, a fault in the connecting cable itself can cause this phenomenon. After replacing a new connecting cable, the fault is eliminated.

Fault 4

4.1 Fault Phenomenon

The endoscope image is dark.

4.2 Fault Analysis and Repair

First, check if the endoscope light guide is broken or partially broken, and whether the monitor brightness, contrast, and host keyboard settings are correct, and whether the light source brightness level setting is correct. Second, if the bulb's lifespan is over, it will also affect the image; in this case, the bulb needs to be replaced. If the above problems are ruled out, then the possibility of dust inside the light source obscuring the optical path and causing a decrease in brightness should be considered. In this case, the light source casing needs to be opened, and the internal optical path needs to be cleaned.

Summary

As a medical equipment repair technician in a hospital, one must first understand the basic working principles of the equipment being repaired. A clear mind is needed to carefully analyze the equipment's malfunction phenomena. During the repair process, follow the principle of going from simple to complex and from the periphery to the center, analyzing step by step and judging the true cause of the malfunction based on the working principle. In addition, repairs require boldness and meticulousness, and the courage to get one's hands dirty. Only in this way can fault diagnosis and troubleshooting be better performed, and practical problems can be solved quickly and at a lower cost.

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