On Tue, 24 Oct 2017 10:43:25 -0700 (PDT), wrote:

I just got a 1981 townhouse.
It's got an Edwards 2 tone chime box, front and back doorbell push buttons and it's running on a Edwards No. 590 transformer with 10V. - 5V.A. Output voltage.

I would like to change the front doorbell push button to a new Ring Pro which runs on 24V.

Question: If I change the 10V. Transformer to a 24V., will my Chime box be OK or do I also have to get a new chime box?

Thank you.

Just looking at the instructions it looks like you still use the
existing transformer and they get the voltage they need from the "pro
power kit" you install. They also warn you that the existing chime may
stop working and that there is a chime in the kit.
The PDFs are at the bottom of that Amazon ad. See if it makes sense to
you or call the 800 number they list.