Definitely good ideas, Harvey! I particularly like the idea of pulsing a current limited supply into the rail and checking around along that rail for the lowest amplitude pulse. That should get you close to the offending component! Have to remember that one....
"Harvey White wrote:
There's another way, that's to take a current limited supply and pulse
it on and off. For a supply of X amps, I'd limit it to x/10 amps.
Now, if you have an HP current probe, the one that's made for shorted
nodes, you can see where the bright lights go, and that shows you the
track where the short is.
You might be able to make a probe that does that.
With this same setup, you can also take a probe and with a high
sensitivity range on the scope, look for the lowest amplitude of
pulse. You'd like to measure across the component itself, if at all
This is a different implementation of the second mode.