Tom,
Other tips are tighten the screw, then carefully back it out. Put a small dab of super glue on screwdriver and apply to screw. Get a really sharp Phillips blade and love tap it into screw head before trying to remove screw. Sears sells screw removal bits, however they are usually larger then case screws. Note: many of the screws and hardware on Kenwood radios are metric sizes. A machine shop can rescue. If these ideas don't work call me. 
Lynn Roberts
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