Are all miners on the controller the same type? Must be all 841's. Maybe the others are 821's? You cannot mix them on 1 controller.
As for troubleshooting - um, you *did* look at page-1 here right?

Yep, they are all 841s , and yes, i read through the troubleshooting guide. I'll add additional details later i want to run cgminer with the -D (debug) switch to see what comes up