1. If the compatibility is originally set on 5 (or whatever number it’s on right now), make sure it sits securely on that number. If not move it to the other numbers to see if that pulsating will go away then back on to where it was at before (usually number 5).
2. Try new batteries
* check to see if there’s a cell phone or wireless router nearby. sometimes those can cause pulsating or vibrating noises even when the phone is not ringing.