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Leich ~ 900 Convertible line wiring?

Started by Mr. Bones, November 23, 2012, 12:29:26 AM

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Mr. Bones

Good evening. I am trying to connect a Leich (Thanks for the ID, Dennis!) magneto telephone to my copper pair, via a biscuit jack / modular cable interface, as an answer-only phone with ringer.

The biscuit jack and cable are known good, since I used it the prior the same day, and since, to hook up other rotaries, with full success. Ditto for the wall jack, and the line to it.

The telephone in question, I believe to be a Leich 901B?, from what I've been able to ascertain on the web, epay, and various forums / sites so far. It has the magneto w/ handle, vs blank, or rotary dial. I can provide pics as required.

The insulation is pretty cracked, painted, and hard to discern on the spade end of the line wires, but I hooked up what I believed to be the red and green to the corresponding jack terminals.

Within a very short time after I plug into the house jack, it takes the line off hook, and all the other phones,  tells me 'if you wish to make a call, please hang up, and dial again', etc. Too quick to call and test the ringer from my cell phone, at any rate.

The switchhook has zero effect; only unplugging the Leich brings the line back so that I can make / receive calls on any other phone in the house.

I understand these were wired for a variety of different battery power situations, just wondered if somebody out there had the time to help a newbie get another cool old phone up and running?

By the way, searching the forum turned up zero hits for Leich..., so sorry to bother y'all.

Thanks in advance!

   Mr. Bones
      Rubricollis Ferus


Welcome to the forum!

Yeah that  is going to be a fair bit of work to convert. It must be possible  to do though becasue there was a "dial conversion kit" for them which means that it could work without the batteries needed for Magneto operation.

When searching on this forum you pretty much want to make sure that you are on the home page as if you are in one of the boards whe nyou search, it will only search that board. I seem to recall someone posting the paperwork that came with a dial conversion kit for a Leich phone.

There are more!



Welcome to the forum.

I don't know that model, but generally many magneto telephones did not have a capacitor in series with the ringer.

The first simple test would be to remove one of the ringer wires, and test if the problem with dialing from the other phones are solved.

It is several ways to convert a magneto to cb, but that has to come later.



Looking at the diagram:
I would try this:
Move ringer wire from 10 to 14.
put a resistor of approx 200-330 ohms between 3 and 1.

This is a quite simple conversion, but it should work.

Removing yellow from inductor (tape it) would protect against the risk of sending ringing current out on a network not designed for this.



 Mr. Bones ,
                  I converted mine and it works great.   stub
Kenneth Stubblefield


Good drawing Stub. Mr. Bones wants to convert it so he can answer but not dial since he doesn't have a dial for it so he will likely need a little help eliminating the dial from the circuit. And presumably he won't be able to have the Magneto connected to ring the bells when the handle is turned.


Mr. Bones

Thanks to all for the great info, and please keep it coming :-)

I will pop the case tomorrow, and get after it with the Fluke T-5/1000 to ascertain which leads are which on the line cord, as well as other measurements to assure no opens or shorts, etc., ad nauseum.

Stub, the drawing was invaluable, and much more clear and decipherable than any others I have found. (I'm an electrician, by the way ;-)) Many thanks for your contribution; it is greatly appreciated, sir!

AE_collector is correct: I want the phone to be a ringing, non-dialable extension. It isn't like I need another phone in the house, but I ALWAYS can find a place for one lol! One more pair of bells is always a welcome sound, to my ears, at least. ;-)

Perhaps, if I run across the right situation, I'll get a blank dial one, or even a dial 901x, but this one has too cool a vintage look to modify. It is in extremely nice condition, early bright metal base, nearly flawless bakelite case with good sheen...

I've seen plenty on ePay in sorrowful, bottom of the barn, roof-been-leakin, nigh-on-to-forty-years-or-more condition, to sacrifice this one by any irreversible modifications.

If a bit of re-wiring neuters the mag, enables the ringer, and makes it a functional member of my telephony system here at Firebase Bonedaddy Forward, then superb. If not, I'll pursue another course of action.

We will soon find out. Kind of the best part of collecting, to me: making it work! To paraphrase: "Winning that ePay auction:$100.00. Shipping:$15.00. Having a resource like CRPF members:PRICELESS!!"

(No, I didn't buy the 901 off of  ePay. It came with a pretty good AE-40 for $25 off of  Craigslist.)

Improvise. Adapt. Overcome. (Collect)
   Mr. Bones
      Rubricollis Ferus


All you need to do is follow the instructions for conversion to common battery in the lower right.  Use the instructions for metallic (bridged) ringing, and you don't need to remove the generator, but do unhook it.  Follow the step for no dial.
-Bill G


Great wiring diagram.

With to days resources, I will claim it is easier and better to do it my way.

With all respect to the old designers:
A ringer capacitor bipolar at 0.47 to 1 microfarad rated 200V or more is lo cost, small and available.
Put it in series with the ringer. (0.47 gives weaker ring, and less REN load than 1uF.)
A resistor of about 220 ohms 1/2W costs nearly noting.

You will keep a good anti sidetone function, witch nearly are lost at the original diagram.
Its simpler to do, and rewire back if needed.
You may adjust the REN load with choice of capacitor.

Why that possible switch between 7 and 11?
The winding direction of the transformer/induction coil may be of importance when put into the same circuit, but it doesn't matter when powered from a battery.



To not be to ignorant to the original design, I have noticed that someone want to keep the magneto to ring their own ringer, but not send ringer current to the system.

The drawing under may work, when cranking you, short for sending out ringing, but rings your own ringer.

This principle may be used on all magneto telephones with such switch.

Whats the drawback?

The moment of switching when starting/stopping cranking may give a short pulse on line.

I would not have done this.