BubbaJim stated:

Will the affected color(s) convergence adjust vertically and
horizontally? If they do , resistors probably are NOT the problem, you
could be looking at a bad yoke (only saw it once) or a bad DCU. Pull
the affected yoke and look for evidence of arcing/burning.
bubbajim

Yes, I am able to make both adjustments on the blue, which is the problem
gun. Now, what is a DCU? I haven't heard mention of this acronym yet.

Thank you,
Tom