[russell_w_b]

Hello Deckstar, and welcome to the forum.

You will sometimes get a transient pulse through the bell (and capacitor in the NTE) when lifting and replacing the handset; it's quite normal and depends on where the armature rests after it stops ringing. Does it tinkle when dialling? Have you disconnected the telephone's internal capacitor by breaking links either side of terminals T9 and T10? When it does ring, is it a healthy, consistent ring?

I get the same, occasionally, and sometimes you can hear the armature pulling over but not striking the bell. The polarised bells are very sensitive indeed (some more than others) and I have known me answer the telephone with an initial 'ting' as the exchange relay goes over giving rise to a transient d.c. pulse before ringing current is applied.

Some US telephones (and very, very early UK ones) had a biassed armature where a small spring would pull the bell to the same rest position after ringing, but the 59A bell in your telephone can land anywhere, and, as such, is at the behest of whether a positive or negative-going transient pulse is applied with relation to the polarity of the bobbin magnets.