It’s not unusual for transformers to be found in various locations. Like I said, mine’s in a basement mechanical room and is easily accessible. Your mother’s transformer could be in a similar location (i.e., near a furnace), next to a breaker panel, behind the mechanical chime (if you take that off the wall to see what the wiring situation is coming into the chime), or elsewhere. Some Forum users have reported finding their doorbell transformers in attics or closets.
I’ll mention/ask this again, too:
Even if you can’t find the transformer or don’t have that photo, you could still potentially use your multimeter to do some testing and determine which wires are connected to what devices within your system. If I was working on this myself, then that would be my preference rather than blindly moving wires around and hoping for the best: If you don’t know what your connections are at baseline and then run into other problems, then you’re unnecessarily complicating things for yourself, because at that point every connection is essentially unknown. That’s why I question this:
What’s the value of moving wires around if you don’t know what they’re connected to at the other ends?
If the wiring diagram (as shown in your original photo molded into the plastic housing on the right) is accurate for the way the transformer, chime, and two buttons were originally installed, and if that was all working correctly before, then I would expect to see six wires (three 2-conductor pairs where each pair has 1 red and 1 white wire) coming together at your chime, but I would also expect to see only three wires connected to your chime’s terminals, and they would all be the same color (though that’s arbitrary with “dumb” doorbell buttons), and each chime terminal would have only a single wire connected. Again, that’s my concern/confusion with this:
If you’re seeing only four wires (2 red, 2 white) coming from the wall into the chime, then I’d wonder where the other two are and what’s happening in the wall behind the chime box.
If you can’t find the transformer, then you could disconnect the Wyze Chime Controller (you already know how that’s wired now because of the photo you included in your first post) and put temporary labels on your 2 red and 2 white house wires that are currently showing in the box so that you know where those started…or at least what their current positions are (which may not be correct). Then you could disconnect those wires, pull the chime off the wall, and see what’s behind it. You might find the transformer and/or another wire pair. If the transformer is there, then you can (hopefully) see what its actual rating is (both V and VA) to make sure it’s going to provide what Video Doorbell v2 expects to see for power, and you can also test the voltage across its terminals using your multimeter’s AC voltage setting. Note: You may want to turn off the breaker for your doorbell transformer’s circuit before connecting/disconnecting these wires, but you’ll need to turn breaker on (power the transformer) when testing its voltage (see below) and when trying to determine which wire pair at the chime is actually connected to your transformer. Even if you don’t find the transformer in the wall behind your chime box, you could still try some testing to get a better idea of what’s going on with your wires.
At this point, I’d also disconnect Video Doorbell v2 and the “dumb” doorbell button so that you have free wires to test and nothing unnecessary in the system to interfere with testing. You don’t want the wire pair for any of the doorbell buttons touching at this time—not touching each other or anything else. You want all wires to be free, because you want to use the multimeter to determine which pair of wires is connected to your powered transformer (assuming its breaker is still on; if not, then you’ll need to turn on the breaker for your doorbell transformer prior to testing voltage), and you can do that by using your multimeter in AC voltage mode and methodically testing each wire pair until you see an expected voltage. What you’d be looking for is ≥16 V AC from one wire pair. Hopefully you’d also see two other wire pairs that don’t register any voltage. You’d then label this wire pair that’s showing the expected voltage as being your transformer pair and set that aside (i.e., tape it out of the way temporarily or otherwise leave a clue for yourself that you’re done with this pair now because you know what it is).
To figure out the remaining two wire pairs (assuming this is what you see), you’d want your multimeter to be set for measuring continuity or resistance.
Important:
When testing resistance/continuity, you should ensure that power to whatever circuit or circuit element you're testing is OFF in order to avoid erroneous readings and damage to your multimeter. These two loops—to your front and rear doorbell button locations—should already be disconnected from power, because you should've disconnected them previously when freeing all the wires and removing your chime from the wall, but you may want to turn off the breaker anyway and then verify that the wire pair you just set aside is no longer registering AC voltage before changing your multimeter's mode.
You’d go to your “dumb” doorbell button location and connect those two wires together so that they’re touching—making one continuous conductor. Then you’d go back to your chime location and start testing wire pairs for resistance. Note that you’d need to change your multimeter’s mode for this. When you find a pair that reads zero or close to it, then you know that you’re measuring a closed circuit—essentially one long wire going out from one multimeter probe to your doorbell button location and then coming back (because the wires are touching/connected) to the other multimeter probe. You can label that pair appropriately. Then disconnect the wires at that button location and go to the other button location to repeat the test (connect the wires together at this next button’s location and then go back to the chime box location to test from that end) with your remaining wire pair and assure yourself of the wiring pathways. Label those.
If you can do all that and get to a baseline understanding of your system’s current state, then you can connect three white wires together with a nut or other connector (again, the color is arbitrary, and I’m assuming that you’re using typical red and white bell wire pairs). This is the “common” connection noted by the green circle in one of the diagrams I posted above. That would leave you with three red wires, hopefully labeled for their connections/locations. You’d then do this:
- Connect the house red transformer wire and Chime Controller’s red wire to the TRANS terminal on the chime.
- Connect the house red front door wire to the chime’s REAR terminal (because you want only a single tone from that dumb button when you connect and press it).
- Connect the house red back door wire to Chime Controller’s black wire with a nut.
- Connect Chime Controller’s white wire to the FRONT terminal.
Then go reconnect your “dumb” doorbell button and Video Doorbell v2 to the wires at their locations, restore power to the circuit (turn the breaker on), and test.
Without knowing more about what you’re actually dealing with in your mom’s house, this is how I’d plan to proceed. If you have questions or see things you don’t expect, then feel free to ask those and/or share more photos here.