I recently strated flying with a new engine & I really like the % Power indicator my D-120 which helps me keep the power between 70-75% during engine break-in. However, yesterday while flying along at cruise speed 75% power, the indicator stopped working & went to dashed lines. I tried turning the unit OFF & back ON again, but was still not working. Several minutes later, the % Power indicator came back alive. Any ideas what is happening?