Thanks Mike.
"the original EX-800 sysex dump"
Would that be the file "EX800.syx" file listed below?
https://groups.yahoo.com/neo/groups/korgpolyex/files/2%29%20EX-800/Patches%20and%20patch%20dumps/
I do realise that the patches have been scrambled. What I wonder is why the saw wave isn't being generated. Could that be due to incorrect parameters in a patch?