

Reverse Engineering a Schematic from a Circuit Board - coderdude
http://www.instructables.com/id/How-to-reverse-engineer-a-schematic-from-a-circuit/

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dattaway
I found most circuits are based on generic engineering designs. Note the chip
numbers, get datasheets, and draw a basic block diagram. From that, draw up a
mock diagram that could work, then reference the board for the details and
make changes. The result is fairly accurate.

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felixfurtak
Yep, pretty much a waste of time on 4+ layer boards

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bwarp
So true.

I'd argue it's probably a waste of time on greater than 2 layer boards myself
(having had the pleasure of doing this on a Telequipment D83 scope amp module)
unless you want to boil them and get the laminated layers out and then don't
even ask about vias.

What is even more of a pain about doing this is that on traces that carry high
frequencies, intentional parasitic inductances and capacitances are sometimes
designed into the board and there is no way on hell you're going to reverse
engineer them.

If this is for reverse engineering and repair, it's best just to "replace at
the border" i.e. replace the controller assembly with something electrically
compatible much as they did when they went from relay logic to PLCs back in
the 70s and 80s.

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felixfurtak
I think the pros use x-ray

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bwarp
You'd think so but they don't see through ground planes.

