Curve analysis method has been applied in Schneider Magnetic Resonance Imaging Equipment CPU PCB Board Maintenance, viewed from the curve, there is a conduction point and a breakdown point, indicating that the node has semiconductor devices connected.
The curve is ring-shaped, indicating that the capacitance curve is off the vertical axis, and that there is resistance.
The results of this analysis are consistent with the actual MRI PC board circuit diagram. The conduction points and the cutoff points of the three curves are the same, indicating that the semiconductor device is normal. Comparing curves #1, #2,
Obviously the resistance value of node #1 is too low. Check the circuit and find that the resistance of one is shorted. After eliminating the short circuit, the curves 1 and 2 completely match. The curve 3 shows the abnormal capacitance of the node.
The capacitance is much smaller than that shown in Figures above, and it is already shown in curve 3. Therefore, it is estimated that the fault check circuit of another branch circuit has found that the resistor row shown in the figure is disconnected at the point.
After re-welding, node 3 is in line with nodes 1 and 2 so that the node failure is eliminated, and the troubleshooting of analog board has been completed.
Compared with the conventional inspection method, the conventional electronic pc board restoration method should first analyze the working principle of the circuit board, then use the extension board to extend the test board, apply a certain signal to a node, and use a multimeter, oscilloscope and other tools to measure the output waveform of the relevant node. In order to determine the fault.
This kind of operation is not only tedious, but also requires a thorough knowledge of the electronic circuit card systematic principle, that is, sufficient printed circuit board documents and drawing which is not traditionally available from manufacturer but have to acquire by PCB restoration, This method cannot be implemented when there is no extension plate available for maintenance.
