Client reports fault on RM clock, amp gage shows fried solenoid (WM, natch), landscapers had mulched over vb, drag out the 521, start locating, but the tones & null continue past the area I know the valve is in. Locate another vb with good solenoids & the 521 does it's thing. So, what's my course of action? Should I hook-up to the common & the valve wire & try it? Usually the 521 is a cinch; a first for me, help!