I've been having issues with the stability of this camera and made the following observations:
My chime is humming as described here:
H Series Doorbell Camera Quickstart Guide - Nelly's Security
If I wire the resistor as shown in that guide, the humming disappears, but the doorbell will start disconnecting often, so I have to power down the circuit to restart it, at least once every day or two. I decided to disconnect the resistor, as the camera was working well before that. When there is no resistor, the camera works well. It's been on for 4 days now and never went offline. I measured the voltage at the wires coming to the doorbell. No resistor = 19.5V, with resistor 20.6V. Does this mean that the doorbell is so sensitive when the voltage is higher and going over 20V? Does anyone have an alternative solution to stopping the chime from humming, while having a stable camera?
If you're having same the issue I had, the problem with the chime humming is that current is flowing to the doorbell all the time. In a normal setup, current only flows when you depress the doorbell switch. So as the doorbell camera consumes power, the coil in the chime is energized and the plunger is most likely vibrating. To make matters worse, the camera's power consumption fluctuates, often causing the plunger to not just vibrate, but move up and down a bit, adding to the noise. Adding the resistor lowers the current in the loop but may cause the doorbell to not get enough power, which is likely why your doorbell camera is disconnecting.
What can you do? Tie off the plunger so it cannot vibrate. The chime won't work but the smartphone notification will. The chime should be silent, no more humming. If you remove the plunger, you'll greatly lower the inductance of the coil. Voltage on the coil, Vc, is then reduced so the doorbell will see a higher working voltage and may be damaged depending on your transformer's output voltage. Vc=0.5*LI, where I is current and L is inductance. Removing the plunger lowers L, so the voltage across the coil in the chime will be lower and the voltage at the doorbell higher, which may or may not be an issue.
In my case, I don't care about the chime's ding, as I have a wireless doorbell extender kit installed on my chime (my extender kit is old but it is something like this:
https://www.amazon.com/Thomas-Betts-RC3030D-Extend-A-Chime/dp/B0000BYCN1). The transmitter mounts on the chime and you can plug in several chimes around the house, even in the garage, which is great. If I remove the plunger the extender wouldn't see enough of a voltage change on the coil to activate so I zip tied the plunger in place, no more hum, and no need for the load resistor.