Testing IC and Caps

[wui223]

Could somebody teach me how to test for faultiness of IC and capacitors?

[aron]

http://repairfaq.ece.drexel.edu/sam/captest.htm#cttes

for ICs what types?

http://www.geofex.com/fxdebug/bias_prob.htm

[niftydog]

quickest and most effective way of testing IC's is to put them in a circuit that definately works. Usually this is not practical. So instead what you do is to swap a suspect IC with a known good one to see if there's any change. If that fixes the problem, you know you have a dud!

Otherwise, you generally need an oscilloscope and a schematic, then you take an educated guess. Like, I had one the other day that had me going for a bit. Op amp feeding a compander chip - signal very low at the compander input. Disconnect the compander, op amp output was fine. Reconnect the compander, still low signal. Turns out that the op amp lost it's ability to sourc current but could still produce the right voltage into an open circuit load. Swap for a new op amp, everything works!

Capacitors are much harder. The best way is with an RCL meter and some learned knowledge. Cheaper cap meters will help a lot of the time, but only ones that show ESR (equivalent series resistance) will give you a clearer picture.

Other folks make up RC oscillators and check that the resulting frequency correlates with the equations. If it does you can be assured that the capacitance value is correct. This still does not tell you much about the ESR.

So, in other words, the best way for both ICs and caps is to swap them for known good ones and observe the changes.