Contact the Doorbell Museum
If you are inquiring about information, parts or repairs for an existing door chime, you must include photos of your chime or I probably will not be able to help you.
Mechanical or electrical problems must be assessed on individual chimes.
Photos copied from the web or this site will not do as there are many minor variations that must be taken into account.
I try to help whenever possible, usually at no charge. Words like please and thank you go a long way when requesting help.