Here is a newsgroup post but I saw an easier way somewhere. I'm still looking.
Tracy
If you want to modify a 41256 to work as a 4116, here's how to do it:
1. Jumper pin 1 to pin 16.
2. Clip off pin 1.
3. Jumper pin 8 to pin 9.
4. Clip off pin 8.
You are now ready to drop this chip into a socket or board location that's
meant to work with a 4116. No board modifications are necessary.
I have tried this already with several _Missile Command_ boards and it works
just fine. I've found it best to replace all of the original 4116 RAM chips
at the same time; if one original has failed, chances are the others are not
far behind and it's time to replace them all.
Defend cities!
Matt J. McCullar
Arlington, TX