Testing of electronic components of medical electronic equipment

Since the 1980s, the medical industry has introduced many advanced large-scale electronic instruments and equipment, ranging from nuclear magnetism to color ultrasound and monitor. As all life spans increase, from warranty to repair, some devices have entered peak maintenance. Compared with the foreign three or five year replacement of medical equipment, China's medical equipment service time is longer, service speed is faster. So, for our maintenance assurance work, there are a lot of problems. It involves the knowledge, experience and technical level of the maintenance personnel. This article only discusses technical equipment and other equipment.
Background of good maintenance of electronic components of medical electronic equipment
General medical electronic equipment maintenance work is divided into two aspects: the overall maintenance of the circuit board and the maintenance of electronic components on the circuit board.
(1) Maintenance of circuit boards
The electronic control and monitoring part of large electronic medical equipment is mainly composed of some circuit board circuits, any failure of the circuit board will lead to the normal operation of the whole equipment. The so-called circuit board maintenance, is when the equipment failure, through the machine self-inspection or through the judgment found fault circuit board. Replace it with a good circuit board so that the device can work properly again.
(2) Maintenance of electronic components
Each circuit board of medical electronic equipment is composed of many components, such as: resistance, capacitance, diode, various integrated blocks, etc.
When they fail, the circuit board fails. The circuit board is found to be normal after replacement of faulty components.
It can be seen from the above two points that the maintenance of the circuit board is relatively easy, but it requires the technical support of the manufacturer. So relative maintenance cost is certainly very high, less thousands of yuan, more tens of thousands of yuan. There are many equipment with too long service life, manufacturers have stopped production or replacement, money can not necessarily buy the right circuit board. Therefore, it can be seen that the maintenance of electronic components is different from the maintenance of circuit boards. The maintenance of electronic components is relatively complex. General purpose components are always the majority of components on the circuit board. Experience shows that general purpose components account for a larger proportion of vulnerable components. As general-purpose components are produced by multiple manufacturers, they are available at major electronic stores. So the maintenance cost of electronic components is always much lower than the maintenance cost of circuit board.
Testing of electronic components of medical electronic equipment
2. Three steps for the maintenance of electronic components of medical electronic equipment
2.1 Correctly detect faulty components
Identify faulty components on the circuit board using appropriate detectors. At present, a large number of medical electronic equipment use microelectronic technology and computer technology, its circuit board is very complex, so the fault detection work needs experienced electronic maintenance engineers to complete. Use several commonly used universal test instruments in maintenance.
(1) Logic analyzer can be used to detect all kinds of digital circuit fault requirements detailed technical information, online testing conditions.
(2) Dynamic logic comparator can be used to detect functional and parameter faults of digital devices. Can be used without technical information, with on-line test strip under use. When there is no on-line test condition, the test effect of 012 board is good.
(3) Online maintenance tester for various components of the end port test and digital device function test, can be used in the absence of drawings and no online testing conditions.
(4) Oscilloscope can detect the functional and parametric faults of analog and digital devices, but has weak testing function for digital circuits. Detailed technical information and on-line test conditions are required.
(5) The multimeter can detect the port DC characteristics of various components, which is the most commonly used method in the absence of technical information and online testing conditions before there is no online maintenance tester.
2.2 Correct component disassembly and welding
That is, the faulty components are welded down from the circuit board, and then the good components are welded up. Early circuit boards mostly use double - layer panel double - row - in - line package components. Maintenance personnel can successfully complete this task with a tin magnet and an electric soldering iron. With the development and improvement of technology, a large number of printed circuit boards, surface mount technology and high density pin packaging devices are used in recent years. Therefore, disassembly welding has become an increasingly technical work. Special welding tools must be used, otherwise in case of error will cause irreparable consequences.
2.3 Correctly locate and back up components
For faulty components, they can be easily purchased from the market. If a particular part breaks, we have to go to the manufacturer and try to fix the problem. This is the main reason why the maintenance of medical electronics cannot guarantee 100% success. In a word, electronic component maintenance of medical electronic equipment is a very complicated work. However, it can really solve the big problems in hospitals and create benefits, so hospitals are paying more and more attention to it.

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