On Saturday, 13 July 2019 16:43:19 UTC+1, Muddymike wrote:
We have an ancient Freidland door chime which Dongs but no longer
Dings:-) Ive been looking for a replacement but cant work out if I need
an AC or DC bell unit to continue using the current 12v Freidland 764
transformer.

So far Google hasn't been very helpful, do any of you know if this thing
is DC or AC?

Mike

They usually just need cleaning up a bit. Wire wool. Nooil.
ISTR on some models, it went ding dong on one push and just ding on the other. So you knew which door had the visitor.

I further STR that it had a leaf spring that centred the solenoid.