I was going to suggest Randy Fromm, but as I recall that wasn't working out for you.
There are some good resources in the
Restoration section of the wiki, but much of the board repair stuff is buried at places like ArcArc or Ionpool and may take some digging.
I don't have my copy handy, but I think that Atari's The Book talks about using logic probes (and is a good thing to have in any case). There are scans of it available out there.