News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

I Just Couldn't Resist

Started by LarryInMichigan, October 19, 2009, 05:52:44 PM

Previous topic - Next topic

Phonesrfun

By looking at the routing of the wires, I would say that Chicago used the standard wiring for a magneto wall set.  If anyone has Old Time Telephones! by Ralph Meyer, that diagram is on page 103.  That was the basis for all local battery sets at the time.  There are not many variances.

-Bill G

Dan/Panther

Dennis;
All the internal components of my phone are intact, and everything added used exsisting screw holes. I can put it back the way it was, and no one would ever know it had been done.
D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

Phonesrfun

Larry:

Were you able to find a larger capacitor?

-Bill G

LarryInMichigan

Bill,

I haven't looked for a capacitor yet.  I have done some general preparation work, like polishing the bells and trying to figure out where to mount the phone (I have a pretty small house).  I removed the magneto which reduced the weight by about 12 pounds so that it will be easier to mount and less likely to fall off of the wall once mounted.  I was thinking of looking for a junk phone (preferably touch-tone) next week whose internals I can use to power the wall phone.  I figured that something like a WE/ITT desk phone might already include an appropriate capacitor.

Thank You

Larry

LarryInMichigan

#19
Today I finished my wall phone project.  I bought a dirty 1973 WE2500 at a flea market and donated its network and keypad to the wall phone.  I connected a 1μF capacitor and a 1KΩ resistor (bought at Radio Shack) in series with the ringer coils and squirted a tiny bit of lubricant into the clapper pivot, mounted the phone on a kitchen wall, and connected it to my line via the two screw terminals on the top.  I used the phone's existing wiring as much as possible and did not drill any holes (though I used three small wood screws in the interior).  The phone now works well, and the ringer sounds great.  The output from the receiver is still a bit low, but good enough for normal circumstances.  I am really impressed by how sensitive the transmitter is without my having done anything to it, although it makes me sound like I am speaking though a tin tube.  I may be the first one to actually use the phone (as a phone and not just decor) in 75 years or more.

Larry




Phonesrfun

Excellent.  You work fast!

And you are probably right.  Unaltered, that phone would have only been decor all these years.
-Bill G

Phonesrfun

Larry:

You realize we're going to require pictures, don't you?
-Bill G

Dan/Panther

Larry;
I find the same thing with the receiver, a little weak, but still useable.
D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

foots

Larry, how did you get the micro symbol and the ohm symbol in your post? Do you have one of those scientific keyboards or something?
"Ain't Worryin' 'Bout Nothin"

LarryInMichigan

#24
foots,

I pasted them from the Windows "Character Map" utility (under "Accessories").

Larry

dsk

it seems like magnets "like to be used"  an weakens, when stored as an open circuit.
This gives hope for more sound.
Adjusting the membrane may be an idea too. The membrane should be as near the magnet as possible, but not touch it when it is in use.  This is often adjusted by putting rings of paper between the membrane and its rest. Pushing on the membrane with one finger cold make it touching the magnet.
This may have different solutions from make to make.  I have only done this at LME and EB receivers.

dsk

LarryInMichigan

I made a couple of adjustments to the Chicago phone today.  The ringer was too loud, so I added a 2.2K resistor.  There is now a 1 MF capacitor and 3.2 K ohms in series with the ringer.  The volume is more acceptable now.

The more exciting development is that the receiver now works very well.  As I previously mentioned, the output volume from the receiver was poor, but it was still usable (as long as there wasn't much ambient noise in the room).  Today, for fun, I inserted a small sheet of paper between the electromagnet and diaphragm and tightened the receiver cap.  There was not much improvement, so I reopened the receiver, removed the paper, and replaced the cap.  After I tightened the cap, the output from the receiver was dramatically improved.  It is now as loud as my candlestick receiver, louder than a typical 500.  I am wondering if my tightening of the cap with the paper between the magnet and diaphragm bent the diaphragm just enough to create the ideal spacing.  D/P, you may want to try this experiment on your phone.

A few days ago, I was in the kitchen when a co-worker called.  I picked up the call on this phone, and he said that I sounded different, like I was far away, but loud enough to hear.  I tried to explain to him that transmitters from the 1910's had different frequency response than newer ones, but he didn't appreciate it.  It might be interesting to note that he was using an IP/ethernet phone to call me.  Other people have said that I sounded fine while talking on that phone.  I have to admit though, that standing by the wall and holding a heavy receiver cup to my ear is not the most comfortable way to conduct a conversation.

Larry

McHeath

Always amazing that an electric product made almost a hundred years ago can still be used.  Well done. 

Phonesrfun

The one thing I object to in using these old wall phones is the strain of standing there and having to hold the receiver to the ear, and having no way to cradle it on my shoulder.  There are phones that were used in railroad applications and other applications where someone would be on the phone for long periods of time to use a headphone that had a headband to aleviate the problem of holding it there.

We seem to have come full circle.  My cell phone is hard to understand the other party and impossible to cradle it between my shoulder and my ear.  In fact, in many respects, the old time telephones had much better speech quality than cell phones or some VoIP based systems. 

Some older phone companies charged an arm and a leg for measured services, so people tended to be much shorter on their phone conversations.

Also, it is probably true that the tinny and hollow sound of the old transmitters of the day were the state of the art in technology at the time.  People were in awe that they could call across town and all over the country and even be heard at all.  It was just what they were used to.  Innovations in transmitter and receiver design in the 30's gave way to some pretty impressive improvements in speech quality.   Coupled with better switching and transmission circuits, the phone system got to be pretty good, and for the last 60 or 70 years we have become so used to the excellent results that a phone from the 20's or before sounds pretty bad, but certainly not objectionable, even today.

Larry, you have done some pretty good work in converting the phone without destroying its originality or value.  The way you have done it makes it so that you can easily convert it back for overall originality.  Good job.
-Bill G

LarryInMichigan

It's worth noting that having a phone like this on the wall really impresses and amazes visitors, especially when I tell them that it really works, and they can hear it ring by dialing my number from their mobile phone. 

Larry