Michael Black wrote:

Ken Weitzel ) writes:


Fred McKenzie wrote:



In article , Don Bowey
wrote:




Good discussion, but one small correction: When you dial, the dial contacts
open the current path and then close the path for each pulse. During the
time that set of contacts is open, another set is closed, shorting out the
earpiece so there is no click in the ear. The CO reads each pulsed
open-interval. When the string of (one to ten) open pulses completes, the
current path is simply maintained by the closed dial contacts.


Don-

I stand corrected, as Ken also noted.

From your explanation, it would seem that Adam should look for an open
earphone connection as one possible cause of his symptoms.


Hi...

Went out to the shed, searched around a bit, and came up with an old
rotary dial phone.

Not nearly as old as we're looking for (plastic, maybe the '60's?), but
perhaps better than nothing. If the OP would like I'll be happy to take
it apart a make up a bit of a schematic for it. Might be helpful.



Did they really change much, after the obvious point where dials were
introduced? One reason they were always reliable was that they were
so simple, and there's little reason to change that until the time
when electronics started being added.

Michael



I think the 500 set had some varistors to regulate the volume out of the
mic. (transmitter).
The intent was to make all telephones the same volume when the signal
reached the Central Office.

Bill K7NOM