I have just restored a 4 switch Vader using a donor 2600 Long Rainbow.Sacrilige I know but I used all the chips from the 2600 Revision D board which was a pain as they were all soldered in place.Replanted them into my dead Vader but still no good.It turned out to be the large Capacitor just below the on/off switch (on a PAL board).So after almost giving up and running back and forth trying the board out after each chip was inserted,it turned out to be a lousy Capacitor!Moral of the story?Dont always dive straight in and assume the Chips are at fault,they usually are not.It is normally a simple component that causes a V.C.S to malfunction.Oh,and yes,i have fired up a bare Vader motherboard with only the PSU and RF lead in,totally safe,mind you,we have Laminate Flooring!I wouldnt try it on carpet,especially deep pile.