JRS Mystery Modular?

This one in via Jeff of The Tangeant Project. Anyone know what it is?

Some bits from Jeff:
"I have a collection of odd old modular things that a friend had salvaged from the UMASS music department dumpster. He gave them to me a couple years ago and I have no idea what they are or what they do. I've attached a pic of one of them [i have 3 of this module and another different thing - a VCA bank if I recall]. I searched high and low and nobody can identify them - the closest anyone came was some sort of custom made 'daisy' modular, but that was not even a solid bit of info. They are not in good condition - all the barrier strips for powering them are missing and some chip sockets are empty, but the internal wiring seems to be intact and most of the boards are fully populated. They are just collecting dust in my basement."

Followed with the second image:
"The only identification i have found is an etching with the letters 'JRS' on all of them, and this module seems to be a "PWG-2" ['pulse wave generator'?].

So it's some sort of JRS modular system that is a mystery to everyone - a friend even contacted some people in academia that worked at UMASS and one of them said they recalled seeing it but never used it or knew what it did.

I've just been so afraid to do ANTHING with these, as i can't even tell what they need voltage/current-wise. i suppose somebody with more electronics chops than i could look at some of the volatage ratings on components[caps, resistors] and make a decent guess and not blow it up, but that person is not me. Of the 3 of this particular box, a couple have hand-written labels on them that say 'clock bad' and that would seem to be a major function, but who knows..."