I want to read a printed circuit board but the wiring is not clear, how can I do this?

Question

I want to trace the connections and the components of a circuit and draw it in Orcad but the wiring is hard to trace, is there a book or a tutorial that I can read that will help me read PCBs

Answer 1

if your PCB is a multi-layer PCB you are generally out of luck
you need a very complicated and expensive piece of equipment to do that
however if it is a single or double sided PCB, you draw all the pads on a piece of paper,track what you can by eye and draw it on the paper. for the pieces you cannot track use a multimeter to measure continuity between individual pads on the PCB and complete your drawing
it is a very tedious and comber some process but it is the only way if you cannot afford the equipment

Answer 2

Making a schematic from a PCB takes time and patience. The best way I've found is to try and see what you can, but never assume that because you see a trace that you know where it's going. Always use a digital multimeter and test connections from point to point, using either the ohm or continuity setting. A good thing to do is to connect one probe of the DMM to the positive power connection. Probe around looking for zero ohm readings. On your schematic, record which components are directly connected to power. Do the same for ground, or the negative connection to power. Find all of your grounded components and record to your schematic accordingly. The fun part is connecting the dots in the middle of the circuit. I say "fun" rather loosly, because it could be very time consuming and tedious. Slowly but surely a schematic will develope, and it should get a little easier as you go, because you can break the circuit up into different groups and knock out one at a time. Good luck.

Answer 3

if your reading directly off a PCB then... well... i dont think there is a book to help. You will just have to trace it out and mark out the components that connect with either various colored markers or tags. even then u may need a volt meter to check connectivity. If the has more then two layers, your gonna need the voltmeter cause will not be able to trace some of the blind via's with your eye. And if your board was a print out, your outta luck