finding obsolete components??

From: Robert Wolcott (rwolcott23_at_yahoo.com)
Date: 11/30/04 

Date: Mon, 29 Nov 2004 18:45:47 -0800

I am repairing a laser power supply that was made in 1978 and can only
manage to find exact replacement components for 60% of the parts (diodes,
transistors, etc...). Is there some magic resource somewhere that allows
one to find current equivalents to discontinued parts? How is this
generally done?

Thanks,
Bob