We often start a balance job by haphazardly placing our tach and tape. Because both the tach and tape are well engineered, we may go on without a problem. But just a little attention to some of the common tach signal problems is usually all it takes to avoid having to restart a botched attempt at field balancing. What should be avoided when setting up a tachometer?
1. Don't place your tach too close to the rotor.
2. Don't place your tach pointing perpendicular to the rotor.
3. Don't use old reflective tape that may not be in proper working condition.
4. Don't use a tach with dirty lenses.
Doing everything we have suggested here could take all of 5 minutes (if you work slowly) at the beginning of a field balance job, but it could save a lot!