Hi folks,
I used thack to typeset my dissertation on v7 circa 1988. It converts C/A/T codes to
postscript. i have no idea if it will cope with eqn or pic but it was enough for nicely
formatted text as i remember.
this is the patch/bugfix with a link to the original package.
https://www.tuhs.org/Usenet/comp.sources.misc/1989-July/001073.html
-Steve