PCB board testing tips

1, detecting the PCB larger resistance test meter
　　measuring dc voltage integrated circuit pin, the header should be used in greater than 20KΩ resistance Meter / V, otherwise there will be large measurement error of some pin voltage.
　　2, detecting the PCB to be noted that power dissipation of an integrated circuit
　　power IC to be good heat dissipation is allowed without the radiator to operate at a high power.
　　3, detecting the PCB lead to a reasonable
　　if necessary external components affixed in place inside the integrated circuit part is damaged, small components should be used, and the wiring is reasonable to avoid unnecessary parasitic coupling, in particular properly handle and audio amplifier IC preamplifier circuit between the ground terminal.
　　4, to ensure the detection of welding quality PCB board
　　does weld welding, solder bulk, porosity likely to cause Weld. Welding time not more than 3 seconds, the power application iron type heat around 25W. The integrated circuit has been welded to carefully check, preferably with ohmmeter whether short-circuiting between the pin, the solder adhesion phenomenon and then confirm that no power.
　　5, detecting the PCB do not easily damage the integrated circuit is judged
　　not to easily determine the integrated circuit is damaged, because the vast majority of integrated circuits directly coupled, once a circuit is not normal, the voltage may cause multiple changes, and these changes are not must be an integrated circuit caused by damage, when measured further in some cases consistent with or close to normal pin voltage, can not necessarily be described integrated circuit is good. Because some soft failure does not cause a change in the DC voltage. More details can be found problems:https://www.jiepei.com/g599。