My Skybell HD also had a buzzing noise but what was worse was my chime would also repeatedly ring! It was very annoying.
I installed it with my mechanical Nutone chime (mdl BK131LSN-1) which is on Skybell’s supported chime list.
I had to disconnect it. Tested voltage at original pushbutton doorbell and I got 16.5V. Voltage at Nutone C905 transformer (16V 10VA) was also 16.5V. My building is less than 1 year old.
I don’t know if my Skybell HD was defective but when I had it connected, the voltage at the chime “Front” screw fluctuated from 3V-9V or more which caused the chime to go off. When I reconnected my push button, the voltage at the “Front” screw was 0V.
Technical support wanted me to change the transformer, saying that usual transformers give off a little more than what they are rated at (19V for 16V transformer) and since mine gives off 16.5V, it is unusually low. He said Skybell HD has electronics in it that may cause Skybell HD to shut off and turn on if the voltage is too low and that may be why I have multiple rings. But 16VAC is in the specified range for Skybell HD. Seems to me, more likely my Skybell is defective.
Anyway, after a night and hours of looking for solutions, I found this thread. I saw people using 1/2 watt 10 ohm resistors for their buzzing. But my problem was a higher voltage and repeated ringing. I bought a $1.60 10-Watt 10-ohm through hole resistor package at Fry’s. Two resistors inside. (Also bought 1W 10 ohm resistor and 5W 10 ohm resistors because I was unsure if 1/2 watt resistor would reduce the voltage enough for my case. )
I used needle nose pliers to curl the 10W 10ohm resistor wires around the “Trans” and “Front” screws in the chime. No soldering needed. Voltmeter reads 1V AC at the Chime now and I don’t hear the buzz and there is no more constant ringing. The Skybell HD rings and works as expected now. Guess no need to test out the 5W or 1W resistors. Not sure why it is reading 1V at the “Front” now. But it works.
One word of advice to Skybell HD installers: if you are not careful and do not push the Skybell relatively hard to make it flush to the connection screws on the mounting bracket while you tighten the screw underneath the Skybell HD, the screw underneath the Skybell HD can dig into the plastic and weaken it so that when you let go, the bottom half slowly eases off the connection pads on the mounting bracket and the Skybell loses power. Happened to me. Had to push hard and screw it all the way to make it stay powered on.
Anyway, the resistor looks pretty bulky and the packaging is labelled “flameproof” so I hope there will be no issue with it overheating and causing a fire!!! Not sure if I should get a replacement Skybell HD since it works now. Would this be a fire risk if someone keeps pushing the doorbell as someone on electronics stack exchange alluded to??
Hope this helps someone but I’m not an electrician and I don’t know how safe this is. Use at your own risk.