Replacement and maintenance of animal ultrasound machine buttons

1. Principle

The early Aloka black and white animal ultrasound buttons used mechanical contact buttons that are relatively mature in technology but relatively old in style (most of today's animal ultrasounds are touch-type light-touch buttons). In addition, each button of the animal ultrasound machine has 4 pins, 2 of which are used to contact the buttons, and the other 2 pins are designed for the button indicator light. In addition, there is a hole next to each button that is not connected to the printed circuit. Its function is unknown. We analyzed that it may be related to the positioning function when installing the animal ultrasound machine. Early computer keyboard buttons were also mechanical contact, but the keyboard buttons only had 2 pins. The replaced keyboard buttons can only replace the function of the buttons alone and cannot be used as indicator lights. However, most of the buttons of the Aloka animal ultrasound series have corresponding indications on the screen, so under normal circumstances, they will not affect the normal operation of the animal ultrasound machine. Although the various buttons in the entire machine are of different sizes and shapes in appearance, in terms of the structure of the buttons themselves, in fact, the structure of each button is the same.

2. Replacement method

First, use a multimeter to measure whether the keys removed from the computer keyboard have good contact. The reason for using a multimeter is that the pins of the computer keys are flat and wide, and the holes of the animal B-ultrasound machine keys are not large, so they cannot be directly inserted from the pin holes of the animal B-ultrasound machine keys. Instead, the pins of the computer keys must be repaired to the same size as the pin holes of the animal B-ultrasound machine, and then the keys of the animal B-ultrasound machine are removed. Then the computer keys and keycaps are smoothly inserted into the corresponding sockets on the circuit board. One of the key pins is directly soldered to the original contact of the printed circuit. The other pin needs to be connected to the corresponding circuit board with a thin wire. At the same time, because only two feet of the replaced computer keys are subjected to force, resulting in uneven force, and the keys are often disturbed by external forces in daily work, the keys must be securely fixed. Our method is to apply a layer of fixing glue on the bottom of the computer keys. It is worth noting that the fixing glue must be completely dried before it can be used, otherwise it will affect its firmness. This point must be given enough attention.

3. Results

After replacement by this method, the function can basically meet the normal use requirements. It is just that the original keys have status indicators, which can indicate the current working status in real time. After replacing the computer keyboard keys, because the keys themselves do not have status indicators, the current working status cannot be judged from the keys themselves. However, because the working status of most keys has corresponding indications on the screen, it has no obvious impact on normal work; in addition, because the replaced keys are different from the original keys in terms of strength, a short period of adaptation is required.