On 07/05/2015 07:46, Brian-Gaff wrote:
Well says it all. I have a little door phone and after about 6 months trying
to keep the call/bell button has been abandoned in favour of an old bell
push I found in a drawer with a Woolworths price tag on it. This is wired so
it shorts the intercom cable as the original failed one which consisted of
some tacky little push switch on a pcb glued in with heat glue. the Woolies
on is your basic two brass bits sprung apart and a plastic button to short
them together.
Tis worked fine till one of two things happened. Firstly, its not
waterproof and when its really wet, it shorts enough to make the bell sound
or make silly whining noises leaving the amp running with clicks and groans.
Or, the local cold caller or whoever who seems to have been studying finger
karate, squishes it so much the prongs stay shorted out when the finger is
removed.
Most bell pushes seem to still be of this type. I had no idea of the
stringent needs of a bell push in this environment before, so wondered if
anyone else had any bright ideas?
Brian


I think it is an inherent property of bell pushes that the fail quickly.
I once built one using an industrial vandal resistant and water proof
push switch, which worked fine for years on machinery. As a bell push,
inside a porch, it stopped working after about two years.

--
Colin Bignell