Wasted a bit of precious time today trying to find why my arduino chip did nothing when plugged into a board I have made as an interface ( I have used the same pcb before with no problems )
What threw me was the 78L05 on the board was getting hot , which wasted a lot of my time looking for shorts.
It turned out that one of the two tiny 22Pf caps on the crystal was marked 22J and the other 221 ( 220pF ! )
They both came from my same draw, so I dont know when the rogue one got there.
I will now keep my magnifying glass nearby, and accept my age !
Or pick up a set of (expensive) Smart Tweezers and check everything before soldering it on:
I've taken to not keeping loose parts around anymore, for this very reason. Unless it's in original packaging with a label and part number, in the trash it goes. It's just not worth keeping around loose parts (given how inexpensive they are) for the potential of wasting hours debugging.
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The MegaRAM shield: add 128 kilobytes of external RAM to your Arduino Mega/Mega2560
Started doing that once, and found it took X seconds to sort a part, leading to an hourly "rate" of $Y per hour, and realized that Y was disgustingly small. Sadly, that hour is best spent doing other things and just buying new parts as necessary.