IBM 4860 (IBM PCjr) - Some Documentation Pointers
Mike Brutman's web page on the PCjr
Click here.
IBM manual - 'Guide to Operations'
There is a link to the Guide to Operations here.
IBM manual - 'Technical Reference'
There is a link to the Technical Reference at here.
IBM manual - 'Hardware Maintenance and Service'
There is a link to the Hardware Maintenance and Service at here.
IBM 4863 - Monitor for PCjr - Circuit diagram
See here.