You could disconnect the wires at the smart button and see what you have then (assuming this is just a doorbell circuit) Usually the power goes into the chime and they run a switch loop to the button. You should be able to ring the chime straight from the transformer leads. If that doesn't work you have a bad transformer or a bad chime. I suppose you really should find the transformer and remove it if it is bad or at least remove power from it if it is hanging outside a box, buried in the wall and find an accessible place for a new one.
Study Guides for VDV / Structured Cabling Installers
So got into attic seems to be older type install with individual conductors run to each device, typical of older system installed with knob and tube era, where trans former is spliced off K&T wires and nailed to side of joist,
So rewired the chime and located new transformer in accessible attic, got 16 volt trans, read 20.4 at button contacts, chime still only strikes once, on front contact. could the chime be blown since only receiving 13 volts over time?
I'm just noticing this thread. Sounds like the door bell is just the old style with a couple solenoids. you press the front door bell button and the solenoid's armature strikes the first chime(Ding). Release the button, and the spring sends it back to hit the other chime(Dong). The back door bell button causes the 2nd solenoid's armature to hit he 1st chime(Ding), but the spring return doesn't cause it to hit anything. A typical button is open or closed, or perhaps there is an very hi resistance light in the button. No big deal. But if your button becomes a parasitic load, it's flowing current all the time. Maybe enough to cause buzzing. So you push the button, you cause max current to flow and you strike the first bar(Ding). Then, you release the button and the parasitic load still allows enough current flow to fight against the spring return. (No Dong) So in a case like that, you would need to use an interface between the old and the new. Joe
I didn't see any statement about this problem being resolved. This is what I would do to fix it. I would insert my Fluke in the line between the front door chime screw and the front door button/new parasitic load. Test leads in "COM" and "A", Switch to AC A/mA. After any initial, power up, current, settles down, I would record the standby current. Then I would switch to min/max record and ask someone to enter the motion sensing range, I would record the max as the current that should ring the chime, and the steady state current after that, as the parasitic load while it's sending, recording, et,c. Finally, I would have them push the button, and record what I would expect to be the maximum current that should ring the chime. That's it for recording data.
So initial motion sensed or button pressed current should fire the solenoid, but no current less than that. I could perhaps use a current relay between TX HI and the button. Its N.O. contacts would go between the front door screw and TX LO. Only the 2 higher currents would pick the relay and ring the chime.
I would probably prefer to use a source resistance like they mention in their manual and insert a small bridge rectifier in line. I would have the bridge feed a little opto triac circuit, that would fire the chime. Either of these two methods could be used in an interface that they would sell you. But, all in all, I'm not too impressed with what I saw from these folks! How hard would it have been for them to lift their load long enough to allow an armature to return? Joe