Continuity Tester

[paul-f]

Last weekend while at a hamfest looking through a plastic crate full of butt sets, I came across an interesting home brew continuity tester that caught my attention.

It was made from a Leviton knife switch, Holtzer Cabot buzzer and a wall wart, all mounted on a rectangular black-painted board.  The wiring to the probes was relatively modern solid copper. There were no marks on the visible surfaces of the wall wart.

That internal voice told me to get out the screwdriver and look on the bottom of the wall wart.  It was marked Edwards, so it seemed the parts were probably scrounged from an old intercom system.  A closer look showed a KS number, so at least that part had a Bell System connection.

Back home, a little research showed that it was the same power supply that was used with the early 500H and P sets.  Needless to say, it's now part of my early 500 set display.

Anyone want a continuity tester minus power supply?  Just add your own wall wart.  The buzzer works fine.  $5 plus shipping.


Confession:  The crate I found it in was among the "stuff" I took to the hamfest to sell.  I don't remember when I got it, but it must have been at a flea market years ago, before I was interested in 500 sets.  You never know where you'll find a treasure!  (or when, apparently!)

[Dan/Panther]

Lucky you found it out before someone else.
D/P

[paul-f]

How true!

I certainly wasn't the first one to look it over closely.   

Now that I think of it, that crate has probably been to at at least one past phone show.  Whew!   

[jsowers]

Paul, thanks for posting pictures of that transformer. I've always wondered what the original ones looked like. I figured they didn't look like the 2012 transformers with attached blades, which looked like they came a little later in the 1950s, around the time of the 500U and Princess. It figures that the older ones would be bigger and clunkier. I guess the rubber-looking cord is original to the transformer. What a great find!

[paul-f]

You're welcome.  There are more details and photos in the August 2009 Singing Wires article, "Dialing in the Dark."

It includes this scan from a marketing guide.   There's also info in BSP C32.537, Issue 3 (April 1954), available in the TCI Library.

[Greg G.]

Last weekend while at a hamfest looking through a plastic crate full of butt sets, ...

There's a joke in there somewhere...