Discussion about the Korg PolySix synthesizer

When checking for continuity of questionable traces, IMO it's best
to figure out which pins of which IC's are being connected by the suspect
trace.   Then use the DMM to measure directly between the involved pins.
Connecting the pins of the IC's together is the ultimate goal, so it's best
to confirm that it's being achieved.  In other words, you want to check from one 
end to another end, since that's what really matters.   Also, trying to get a good
connection from your probe to a corroded trace is not easy. 

Really, on something like the PolySix, what I would suggest is to print out the 
schematic of just that one board, and "buzz out" with a meter the connections in 
the area that is corroded.   Highlight the traces that have been tested as you go.
If you just try to test the traces that you notice that look bad, it's easy to miss
something.

  My $0.02

     Bob