Equus 3042 analyzer question

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So I broke out my newly purchased 3042 and flipped through the instructions. I clipped the inductive pickup lead onto a running coil wire and got nothing. I checked the manual and it said the 2 C batteries were only needed for resistance testing. It did not mention power to the unit for the RPM test. Was this just an oversight or does this units tach work solely on the coil pickup? I have an inductive timing light but it has 12v power clips. Did I miss something? I believe it has all its test clips and shunts still with it.