G616.  Holding
the board up to light and peering into the space
 between the two boards, I can see quite a few dust clumps. 
 And this might effect the operation how? 
 
Who knows... There's no telling what's actually *in* those clumps.  I know
nothing of the environment(s?) in which the machine was stored.  It's
possible that there could be something conductive in there.
--
Jeffrey S. Sharp
jss(a)subatomix.com