I just had a ring doorbell pro installed. After installation the mechanical bell only dings once. I know the diode is not supposed to be used on a mechanical doorbell. I asked the handyman if he installed the diode and he said no. I’m just wondering if maybe the voltage on the transformer is not high enough? Minimum is 16 V to use the ring doorbell pro and that’s what my transformer is.
But if the handyman did install the diode, will that prevent the mechanical doorbell from ringing twice?

Thanks.