Method 1: check firstly, then measure
Instrument: multimeter and magnifier
When you take a a IMM circuit board which is need to repair in hand, a good habit firstly is to give a visual observationl, if necessary, also with a magnifier, what should you watch?
1. whether there is disconnection;
2. The discrete element such as resistance, electrolytic capacitor, inductance, diode, transistor and so on exist off phenomenon；
3. Is there any broken or adhesion phenomenon in the circuit board connection line?
4. Has anyone ever been repaired? Which component has been repaired? Is there any failure in the aspects of weld and insert operations?
Method 2: Surface Firsly, Then Inside
Instrument: circuit on-line maintenance instrument
If possible, it is better to find a normal circuit board as the comparsion.Then test it with the VI curve scan function from the port. From the surface into the inside, especially the capacitance, in order to assist multimeter.
Method 3: easy firstly, then the hard
Instrument: Circuit on-line maintenance instrument, circuit on-line maintenance instrument
In order to improve the effect of test, before test on the IMM circuit board, you should deal with the board with some technical processing, to try to weaken the interference brought to the test process of negative effect.
1. Preperation: short-circuit the board and weld the big capacitance to decrease the interference of discharge.
2. To test with the exclusive method.
3. comparison test with ASA-VI curve.
Method 4: static analysis firstly, then the dynamic analysis
For the limitation of circuit on-line maintenance instrument, we can just do the static analysis method, so it is better to check whether the power is no nor not, before we start the machine to do dynamic analysis.