ruined a phillips screw, any inspired solution?

OK call me a coward, I went to see Lothar of Tidal who has plenty of machines (even one that goes "ping") and let him do the job. It was indeed necessary to drill away the entire head of the screw. He also had to exchange the bolt as the rest of the screw was impossible to extract. Whilst we were at it, we applied new decent screws everywhere as suggested by Zenblaster.
Much as I like the cdp (we're talking about the Ancient Lektor V), I hate to admit the internal wiring didn't leave the best of all impressions. Which, sadly, goes to show that the proud statement "handmade in the EC" (the same may presumably apply to "US") is in itself not quite the hallmark of quality that we would like it to be. Or am I just too finicky?

Is it possible for an audiophile to be "just too finicky"? This is a question that may need its own thread. Or not...

As a former professional millwright, amateur mechanic (auto and motorcycle) and current computer geek who has encountered stuck and mauled fasteners of many sizes and types I see a number of good suggestions above. All of them work, but knowing which to use and when is the maddening thing. As a starting point, common sense suggests keeping the tool size relative to that of the job.

Still, my preference was always the chisel and big hammer method. Either the job got done or the offending part needed replacement. Hmmm. "Honey, I need to buy a new CDP, this one is beyond repair now..."

Cutting torches are, btw, a godsend.

Try a square wood driver bit. I messed up a phillips screw and it worked for me, just had to take it slow.

Good lord...foooooolishhhhhh! There any number of ways to effectively (and efficiently...and thoroughly) remove a "ruined" screw.

The only foolish question is the one NOT asked.