On Mar 14 2005, 13:37, Dwight K. Elvey wrote: and it Bad contacts in sockets, accumulation of dust and airborne detritus, and problems resoldering or modifying boards when they get older. It's the lighter silicones that cause the problems, though, and if you can find a modern grease that has a smaller spread of molecular weights, the problem will be greatly reduced. The difficulty is in getting rid of the silicones, as they don't wash off, and flow into holes especially when you heat them up. I used to do a lot of commercial repairs, especially on 1980s micros, and I used to hate the ones where people had put gobs of heatsink compund on socketed chips. The compound contains lots of light silicones, which used to get into the sockets and cause bad connections, and then it was a pain to remove the socket and solder in a new one. Of course, the worst were the ones drenched in "contact cleaner" and WD40. -- Pete Peter Turnbull Network Manager University of York