If you are trying to troubleshoot a PCB you probably don’t have the schematic and can just guess where PCB traces go, if you try to follow them manually it can be tedious as you follow vias from one side of the board to the other just to loose the trace under a chip. Sure you can probe around to try to find where the trace goes but with any substantial sized board that can take forever. The technique demonstrated above uses a large finger tip size piece of aluminum foil to quickly dab around the board covering a dozen or more points at a press looking for a common pin. When an area has been found you then just need to probe around and see where the connection was. If the board you are working on is mainly through hole you are probably best off probing around on the rear of the board since items such as electrolytic caps won’t be testable from the component side.Â
I have never seen this technique used before, I wonder if a wand type probe tip could be made that would work a bit better than the foil finger. I am imagining a tip that looks something like a brush that girls use to apply blush, if the puffy thin strands of the brush were conductive this might be the ideal tool.
Via: Electronics Foru