I have PCB that has a pretty sophisticated IC on it (Ethernet switch). Some of the boards work fine but some do not. The reason is that IC doesn't seem to work. There is even no clock on clocking inputs from the crystal and I think that it means that the IC is damaged. My questions are:

  1. Are there some tips how to debug ICs on the PCB, I mean check if the IC is operational or damaged.
  2. What can cause IC damage on the PCB, can it only be electrostatic discharge or maybe there are some common mistakes in the PCB design. There matter is that I have a pretty big amount of that PCBs (~20) and half of them are not operational because the IC doesn't seem to work and I want to find the cause but don't no how...
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    \$\begingroup\$ What if they are not damaged? What if they simply need reset due to invalid power supply rise time? Or what if they are in reset because external circuitry is incorrect? This is all very vague, please post which chip is in question and link to datasheet, and the schematics you have it in. \$\endgroup\$
    – Justme
    Nov 28, 2020 at 14:05
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    \$\begingroup\$ In my 40 years of experience, for known good designs, for boards fresh from production, 90% of issues can be found with a careful inspection. In rough order of frequency: solder bridges, unsoldered pins, parts installed wrong. For a 6 x 8 inch board it might require an hour or more under high magnification. \$\endgroup\$
    – Mattman944
    Nov 28, 2020 at 18:19


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