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So now I have 2 Leich 901's on the way...

Started by Claven2, May 31, 2013, 06:48:38 PM

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Yes, but my nexus phone is to blame for that one - lol


Hmm... so I re-wired the phone tonight using the dial conversion/common battery diagram and got mixed results.

My home line is through the cable company.  They use a phone-specific VOIP, and I don't have a dial or a dialgizmo yet so I can't test dialling.

I used a wall-mount junction box to connect the 4-conductor line to a short modular plug, to the wall jack. 

The handset definitely works.  I did the tests without the casing on, so the phone responds as soon as it's plugged in (off hook).

Now the odd part.  When I plug the phone in, I get a nice strong dial tone, but it immediately starts to fade in volume.  Also, toggling the hook switch does not disconnect the call.

Could this be due to a failing induction coil?

Also, the common battery wiring diagram only shows a 3 conduct line in, but if I leave the red line wire disconnected like in the common battery diagram for the 901, I get nothing other than faint interference from the house wiring.  If I touch the red wire to the No.2 position on the wiring diagram, or if I touch it to the No.3 position (shared with the yellow line wire) I get dial tone.


  ( dead external image link 11/8/17 )


You only need to connect red and green of the line cord to L1 and L2. Don't worry that they are listed as Y (yellow) and  G (green) on the diagram. You don't have to connect anything to the terminal GRD.

Also, run a jumper wire between 10 and 11 until you have a dial.
"C'est pas une restauration, c'est une rénovation."--François Martin.


What about the fading dial tone issue - what is causing that?


Did you place a temporary wire between 10 and 11?
"C'est pas une restauration, c'est une rénovation."--François Martin.


no, I moved the green hookswitch wire from 11 to 10 like the instructions indicated, I didn't shunt it yet.  I can try that later tonight.


Just tried it before work.  Shunted 10 and 11 and disconnected the yellow and black line wires.  I get tone as before, but still fades out to nothing over 20 seconds or so.

I'm thinking either coil or capacitor.  Thoughts?


Ron, if you moved the hook switch wire, that is the same as having the jumper wire. Sorry, I didn't read the fine print in the notes on the diagram.

Are you able to hear steady dial tone on this phone if another phone on the line is off-hook?
"C'est pas une restauration, c'est une rénovation."--François Martin.


I tried that last night, and no I can't.  It performs the same way where the dial tone fades out over time.  Toggling the hook switch brings the signal back to full strength and then it fades again.

I'm thinking it may be the degraded induction coil not keeping up with the voltage requirements of the transmitter, but I'm not sure why the hook switch doesn't seem to be disconnecting the call.  Could be a symptom of the same problem...(?)

Also when I had the red line wire incorrectly at position 2, and I was toggling the hook switch, I accidentally got connected to a wrong number... not sure how.  Maybe I mimicked a pulse dial?


There should be a technical bulletin GTEP 473-414-900AE - Modification to Dial or Battery Operation.  I would think that this would give detailed instructions to convert to dial operation in addition to the schematic diagram.  I haven't been able to find this document anywhere.  


Quote from: JohnInWI on June 07, 2013, 02:46:13 PM
There should be a technical bulletin GTEP 473-414-900AE - Modification to Dial or Battery Operation.  I would think that this would gived detailed instructions to convert to dial operation in addition to the schematic diagram.  I haven't been able to find this document anywhere.  

Unfortunately only 473-414-200 Leich 900-Series Magneto Telephones is shown in the TCI Library.

There is other documentation for them though.



My second "Leich 901 with AE dial" arrived in the mail today.  It's not really what I expected, but may be a blessing in disguise.  For starters, it appears the second phone is NOT actually a Leich 901 - I think it's a Leich 653 (!).

It's a later production phone that came with the factory dial bracket and spacer.  The dial "blank" is actually not really a blank, it's a push-button hookswitch latch.  The phone had already been re-wored to common battery (not sure if factory or done at someone's home?).  The hookswitch latch was disabled in the phone and the ringer was also disconnected and contact isolated with electrical tape. 

Despite it being a phone with these unusual features, all the wiring is really grungy, lots of surface rust on the internals, and the capacitor casing is split pretty bad.  The bakelite is all solid, though dull and the rubber foot gromets are totally worn to nothing.  Interestingly when I plugged it in, I got a great dial tone and it received calls beautifully.

I was able to compare my wiring on the better condition early 901 and I had it all right.  My wiring job is not the issue.  Comparing the two phones more directly, I think my issue is the hook switch.  When the dial tone on the 901 starts to fade, if I jiggle the hook switch contacts, the dial tone jumps back to life.  This phone is also ringing nicely and apart from the sketchy hook switch works very well after all.

I did replace the induction coil on the 901 with the one from the 653.  They are the same part, thankfully and the 653 coil was in far better condition.  I think for now, I'm going to cannibalize the 653 to get the 901 up and running and will get the parts to put the 653 right later on.

I have to decide whether to try and fix (clean? adjust? dunno?) the original hook switch on the 901, or to solder in the working switch from the 653.

Finally, the "Automatic Electric" dial I thought I was going to receive with the second phone is instead a Kellog dial.  Anyone know if this dial will work on my phone?  It's a bit sluggish so I will likely have to tear it down for a clean and lube.

This is before I did any parts swapping.  901 on left, 653 on right (I already removed the dial bracket):

  ( dead external image link 11/8/17 )

Cracked capacitor housing in the 653 - wonder how that happened?  I'm guessing the cardboard liner got wet and swelled at some point, but who knows?

  ( dead external image link 11/8/17 )

grungy wiring.

  ( dead external image link 11/8/17 )

Leich push-button hook switch latch blank. 

  ( dead external image link 11/8/17 )

Hmm... doesn't look like an AE dial to me?  Will this work for me???

  ( dead external image link 11/8/17 )

Original wiring diagram found inside the "653":

  ( dead external image link 11/8/17 )

Interestingly, I like this 6XX series diagram better for the 901 than the actual 901 diagram...?


The contacts on the hook switch can be cleaned with electronic contact cleaner spray and some paper.  Thick brown paper is good.  The Kellogg dial is a copy of the AE design and can be used.



Thanks Larry.  I cleaned the contacts using lighter fluid and a thinned-down Q-tip.  It seems to be working OK now.  I had to clean the dial mount with some dish soap and a soft toothbrush.  The Kellogg dial fits the mount just fine.  I'll have to make a wiring harness for it though, since I don't have one. 

Anyone know how to clean and calibrate this dial?  Is there a manual?

I'm also retie-ing the wiring harness.  So far so good.


ok, I have the dial partly disassembled and am progressing through cleaning.  I'm using this manual for an S-C Type 51A dial, which seems to be a clone of the AE 3" dial, or the Kellogg 21D.

Obviously, I'm not using TCE as the manual suggests, but rather lighter fluid and a series of toothbrushes, Q-tips and pipe cleaners. 

Not sure yet what I'll use for lube, but I'm leaning towards modern Superlube Synhtetic as it does not degrade over time.