Ring 1 doorbell backplate - pinout available?

I have a Ring 1 doorbell that I had out of active service for a while. Re-using now. It works fine on battery, but it’s not working with a transformer attached to the screw terminals on the backplate. I used this same Ring, backplate, and brand of transformer a year ago (before I replaced it with a Ring Pro). The transformer is putting out 24VAC which should be fine. But it’s apparently not getting to the actual Ring doorbell. I’m assuming the voltage from the two screw terminals gets passed to (at least) two of the 12 (3 rows of 4) contact pads. A continuity test with my DVM found 3 pads that map to one of the screw terminals. But I couldn’t find where the other screw terminal passes it’s voltage to. Is there a pinout available that shows what contact pad(s) each of the screw terminals are tied to? I guess the backplate could go bad. I’d rather just confirm that via testing, vs just assuming it is because it’s not working. Thanks. Jeff