DO NOT gut a cluster adapter to make a jrIDE or the PCjr gods will find you. Gut a power sidecar, or a memory sidecar, those are much more common, and also no longer necessary, once you hook up a jrIDE.
Cluster documentation is at
ftp://ftp.oldskool.org/pub/drivers/IBM/ ... chment.pdf but it's nothing special. The adapter comes with no software. I, too, would like to see the software and the technical reference manual...