[COFF] DEC terminal line driver chips?

I've got a number of DEC terminals, ranging from the VT220 to the VT520 (sadly, I got rid of my VT100 and VT102 many years ago, before I started collecting DEC equipment instead of just using it), and some of them have one or more burned out serial ports. Before I start taking them apart to find out what chips were used, I figured I'd check if any of you folks happen to know. I'd like to order a stash of replacements, and it would be nice to have them handy before I clear the work bench to start dismantling terminals... Oh, and for the record: the Q-bus PDP-11/23 uses 9636ACP and 9637ACP for output and input, respectively, while the VAX-11/630 substitutes a 9639ATC optocoupler for the 9637ACP differential receiver. (I have a couple of spare CPU boards with damaged ports, as well, so these are all on my shopping list already.) -tih -- Most people who graduate with CS degrees don't understand the significance of Lisp. Lisp is the most important idea in computer science. --Alan Kay