Nice.
A1 is dead.
System will boot with either or both of the sticks in B1 and C1.
I'm able to also boot it with the third stick in either A2 B2 or C2...but only if there is at least one stick in B1 or C1.
Trying to boot with any combination of memory in A2 B2 or C2 does not work if there is no memory in either B1 or C1. I don't get any beeps. It just sits there and loops without POSTing or spitting out any video. No clues.