I know this is is a dumb question, but do you have, or can you obtain temporarily, an older model phone for testing? Or, Maybe you can take the phone to a house that has some "standard" WE phones? Just trying to think of the quickest way to elimiate the ringer, the deskset, or your incoming voltage.

Also - what I was getting at with the buzzer is I was thinking maybe someone has been in there before you, and switched the leads around improperly. 38 years is a long time for people to play.

Thx
Matt