DUS 60 Digital Ultrasonic Diagnostic Imaging System Service Manual
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careful methods such as pressing and knocking the malfunction parts and components, these
methods can effectively isolate malfunction caused because of poor contact of components and
plug-in board. Do not press and knock the parts so hard to avoid damage. Meanwhile, you should
observe the malfunction phenomenon carefully when pressing and knocking, if the several boards
are connected together, you can press and knock one by one to reduce the malfunction scope.
The above checking ways are simple and intuitionistic; they can help us to find the malfunction
without any instrument sometimes. For example, under the help of the circuit principle you can
find the reason why the impedance is burnt through observing the burnt impedance. It is always
the reason to cause the malfunction, and then the malfunction could be eliminated quickly.
6.6.3. Replacement Isolating the Malfunction
If nothing abnormal or no damaged components has been found through careful observation, you
can use the replacement way to isolate the malfunction if you have spare circuit plug-in board (or
the same type B-mode ultrasound device). The inside circuits consists of many plug-in boards.
Replace the doubtful circuit plug-in board at first. If the instrument works normally after the
replacement, it can be confirmed that the trouble is between the components and parts of this
circuit plug-in board. Then combine the circuit diagram of the principle to analyze the possible
reason causing this trouble in details. This way can save you a lot of time than analyzing in the
system range.
Plug-in board replacement can help you confirm the general scope of the malfunction. If you are
sure about malfunction is in the plug-inboard, you can replace the components if necessary. In
case the integrated circuit adopted the chip socket, you think that one circuit chip is damaged, and
you just have chip socket of the same type, then you can replace it to confirm your analysis. If the
malfunction is eliminated after the replacement, it can prove that there is something wrong with
the circuit chip, you could change it. It is better to change the components for the same type. If
there is no chip socket of the same type, you must assure that the chip socket of different type is
replaceable. Otherwise, the new problem will be caused.
If the malfunction is at the inconvenient location for replacement, reduction to absurdity is
helpful for you. For example, malfunction is confirmed to be at the main board if all the
plug-inboards are checked to be normal.
The replacement method has some localization that your replacement parts should be the same
type of one in device, especially the circuit plug-in board. Otherwise, this method is not
applicable.
6.6.4. Inspection and Maintenance on PCB
Power Inspection
Eyeballing:
Switch on the device firstly. In case the bigger fan doesn’t work, the power board may break
down, or the fan breaks down. Now you need a multimeter to check.
Basic inspection:
Apparatus: Multimeter
Multimeter is used to measure output voltages. If the output voltages are natural value, then enter
into next inspection. Please refer natural voltages value to the table 6-1 and table 6-2, otherwise,
adjustment is needed. If the natural value cannot be reached, that is to say the trouble is on the
power board.
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