Question
I have a 12 zone Hunter Pro C with Irritrol valves. I have erratic controller voltage and my valves are behaving oddly with only #10 working. I tested 3 solenoids at the controller - they are good. I am not getting voltage at the valves except for #10. The controller seems to be trying to run zones simultaneuosly, but even those that have normal voltage like #9 (I think) don't operate. Is this a wiring problem (no digging done recently) or a controller problem?

Here is each of my zones set to run followed by voltage for every zone output at the controller. Readings are stable unless noted otherwise.

#1 28,28,28,28,28,26,4,0,0,0,28,.5
#2 28,28,28,28,28,26,4,0,0,0,28,.5
#3 26,26,26,26,26,23,4,0,0,0,26,.5
#4 26,26,26,26,26,25,4,0,0,0,26,.5
#5 26,26,26,26,26,25,4,0,0,0,26,.5
#6 8,8,8,8,8,26,2,0,0,0,9,.2 - zones 1-5 very jittery
#7 .4,.4,.4,.4,.4,.7,26,0,0,0,.4,0
#8 .4,.4,.4,.4,.4,.7,.7,26,0,0,.4,0
#9 .3,.3,.3,.3,.3,.6,.6,0,26,0,.4,0
#10 .2,.2,.2,.2,.2,.5,.7,0,0,26,.3,0
#11 26,26,26,26,26,23,4,0,0,0,26,.5
#12 .3,.3,.3,.3,.3,.7,.7,0,0,0,.4,26

Answer
I think it is more likely that your controller is the problem.  Try resetting it by removing the power supply and battery backup for 2-3 minutes, then reconnect, reprogram and test.  Also make sure that all the wiring connections both at the controller and the valves are sound.  But it sounds to me like time to replace the controller.