Join Date: May 2010
Location: Calgary, Alberta, Canada
Those are 100K ohm resistors. You won't get much signal to the tach with those resistors in series. My guess is that the resistors are likely not needed 100% of the time, but depending on the driving circuit, it does put the tach at the coil potential. IOW, it doesn't hurt having them in there and will allow the tach to see a logical high (if it needs it).
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