locating shorts Re: HP ScanJet ADF

From: Joe <rigdonj_at_cfl.rr.com>
Date: Sat Jun 1 10:54:05 2002

>Probably a shorted decoupling capacitor (if it's a 'dead short' or close
>to one). I have been known to carefully cut power traces to find out
>which section is shorted, and then home in on the problem.

   That's the way that I've traced shorts down. However since then I've bought a HP Current probe, they're supposed to be able to trace a short down the correct path. I've never had a need for it since I bought it so I dont know how well it works. Has anyone had any experience using one?

Or you can
>desolder components to test them.
>
>Don't use the trick I once saw recomended of applying a high current
>(10's of amps) PSU to attempt to burn out the short. Something will burn
>out, it's true, but it will just be the weakest connection, not
>necessarily the shorted component.

   OUCH! I've never seen that recommended and I sure wouldn't try it. In my experience, a hard short will completely remove the circuit runs from the board. And those can be a real pain to replace, I've seen some runs disappear so completely that it was nearly impossible to tell that they were ever there.


     Joe
>
Received on Sat Jun 01 2002 - 10:54:05 BST