You might find them he http://www.quest-comp.com/

I found them by using this search engine:
http://www.findchips.com/avail

Good luck - Plessey chips are a rare bird now - Roger



Sbc News wrote:
I know these have out of production for a while. If anyone knows of a
source for a dozzen or so, I would be greatful I you would share your
information with me.

Thanks,
Emil
W9NM