Author Topic: AE 40 local battery circuit of the type N-4078 desk set  (Read 1134 times)

Offline NorthernElectric

  • Hero Member
  • *****
  • Posts: 526
AE 40 local battery circuit of the type N-4078 desk set
« on: December 11, 2015, 11:24:59 AM »
Here is a circuit diagram for an AE40 configured for local battery use.  It appears to differ from the standard configuration in that:

a) connections to L1 & L2 are transposed
b) there is an extra connection from the induction coil to L1
c) color code from the 1MF capacitor to L2 is orange instead of brown

It is possible to rewire this phone per the standard wiring configuration without permanent alteration.  I did so by using the L2 terminal as L1, and G as L2 and reconnecting per the standard AE40 wiring diagram.  This leaves the original L1 terminal with the extra connection to the induction coil unused.  It may also be possible to simply move the soldered on lugs around but I didn't think of this until after I had everything connected and working, so I never tried it.  So basically this phone is now configured as a standard AE40 with the exception of the 5MF capacitor instead of 4MF.  I do not know if the induction coil used in this phone is the same as a standard set or what difference the 5MF capacitor would make, but the phone seems to work fine.
Cliff

Offline Jack Ryan

  • Hero Member
  • *****
  • Posts: 813
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #1 on: December 11, 2015, 08:35:35 PM »
I don't have details handy at the moment but AE used at least two different LB circuits for the AE 40. One was a conventional LB circuit using a 1 Ohm primary IC winding and the other was a conventional CB circuit with a minor modification.

Yours is the second and can easily be used as a CB telephone.

In these, an AF choke was added in series with a battery across the transmitter. The AF choke usually looked like another IC.

Without the choke and the battery, the phone is a conventional CB telephone.

Jack

Offline dsk

  • Hero Member
  • *****
  • Posts: 3182
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #2 on: December 12, 2015, 04:53:35 AM »
 :) I love to analyze diagrams like this and find a way to use the telephones as I want to use them.
When I was young, I could cut and re-solder as I wanted, now I like to touch as little as possible to leave it original.
and of course, I like to find my way first, and maybe later look up how it was done originally, so here you have how I would have connected it to a modern POTS line, and how to make the generator box until I could get an original one.

dsk
Please notify me of dead links in my postings.

C*NET +1 999-3011


I have even got a regular New York number :-) 646 570 1796

Offline Jack Ryan

  • Hero Member
  • *****
  • Posts: 813
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #3 on: December 13, 2015, 06:14:53 AM »
So basically this phone is now configured as a standard AE40 with the exception of the 5MF capacitor instead of 4MF.  I do not know if the induction coil used in this phone is the same as a standard set or what difference the 5MF capacitor would make, but the phone seems to work fine.

I forgot to mention earlier that AE used both 4 and 5 uF capacitors on standard CB telephones.

I also implied but did not state explicitly that the IC is the standard CB IC.

Jack
 

unbeldi

  • Guest
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #4 on: March 06, 2017, 08:38:19 PM »
The Automatic Electric N-4078 desk top telephone with the circuit of FORM D-530067-A, which was shown at the beginning of this topic, is a member of the Type 40 series desk sets, and was designed to be used for common battery or local battery service.

When used for local battery service, the proper configuration of a subscriber station with the N-4078 set is to use it in conjunction with the L-594 Magneto and Battery Box.

The L-594 provides a compact ALNICO magneto generator, two No. 6 dry cells, and a choke coil.   The batteries and choke are wired in series across the transmitter and hookswitch of the desk set to power it.

The desk set and magneto & battery box are interconnected with a five-conductor mounting cord.

Here is a complete circuit diagram of this setup.   The set as drawn is is a N-4078 A0 which includes a dial.  For local battery service, of course, the dial is not needed, and is replaced with an apparatus blank.  The wiring schematic that user NorthernElectric posted was likely found in a set without dial, whence it is marked N-4078 B0.

The circuit is drawn in the on-hook state.  All switches are drawn in the convention used by switching engineers.  A normally closed switch is represented as a simple perpendicular bar across a wire trace (覧|覧), and a normally open switch has a cross on the line (覧X覧).  Hookswitches are designation HS, off-normal dial switches are ON, and the dial pulsing switch is DP.

The components of the Type 40 desk telephone are boxed in with the broken purple line.  Everything outside of that box are components of the L-594 magneto battery box.  The five mounting cord wires are visible with labels of their color.  I did not draw any other wire colors.

[update:] The broken blue lines connect the dial and establish wiring when configured for common battery service. Of course, the magneto box is no longer needed for that, and the line connects directly to L1 and L2 inside the desk set.

A picture of the outside of the magneto and battery box is shown in the second picture.
« Last Edit: March 08, 2017, 02:53:55 PM by unbeldi »

Offline dsk

  • Hero Member
  • *****
  • Posts: 3182
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #5 on: March 07, 2017, 03:05:39 AM »
The Automatic Electric N-4078 desk top telephone with the circuit of FORM D-530067-A, which was shown at the beginning of this topic, is a member of the Type 40 series desk sets, and was designed to be used for common battery or local battery service.

When used for local battery service, the proper configuration of a subscriber station with the N-4078 set is to use it in conjunction with the L-594 Magneto and Battery Box.

The L-594 provides a compact ALNICO magneto generator, two No. 6 dry cells, and a choke coil.   The batteries and choke are wired in series across the transmitter and hookswitch of the desk set to power it.

The desk set and magneto & battery box are interconnected with a five-conductor mounting cord.

Here is a complete circuit diagram of this setup.   The set as drawn is is a N-4078 A0 which includes a dial.  For local battery service, of course, the dial is not needed, and is replaced with an apparatus blank.  The wiring schematic that user NorthernElectric posted was likely found in a set without dial, whence it is marked N-4078 B0.

The circuit is drawn in the on-hook state.  All switches are drawn in the convention used by switching engineers.  A normally closed switch is represented as a simple perpendicular bar across a wire trace (覧|覧), and a normally open switch has a cross on the line (覧X覧).  Hookswitches are designation HS, off-normal dial switches are ON, and the dial pulsing switch is DP.

The components of the Type 40 desk telephone are boxed in with the broken purple line.  Everything outside of that box are components of the L-594 magneto battery box.  The five mounting cord wires are visible with labels of their color.  I did not draw any other wire colors.

When configured for common battery service, the broken blue line must be established by moving a wire.

A picture of the outside of the magneto and battery box is shown in the second picture.

Nice, Thank you!
Do you have a scan, or photo of the original drawing too?
Do you know what coil they used as a choke?

dsk
Please notify me of dead links in my postings.

C*NET +1 999-3011


I have even got a regular New York number :-) 646 570 1796

unbeldi

  • Guest
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #6 on: March 07, 2017, 01:55:59 PM »
The original schematic is in the first post of this thread.

Here is a rendition of the magneto box label.

The number of the impedance coil was D-283665-A,  but I don't know its inductance.  It is supposed to have a DC resistance of 10 Ω, and I would observe that this is not exceeded to keep the circuit efficient.  It needs to provide reasonably high impedance at voice frequencies though, so that the battery doesn't short the generated voice current.  10-times that of the transmitter ?

PS: The mounting cord colors don't match the N-4078 wiring diagram or my circuit, but that shouldn't disturb us, I suppose.
« Last Edit: March 07, 2017, 02:15:10 PM by unbeldi »

Offline dsk

  • Hero Member
  • *****
  • Posts: 3182
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #7 on: March 07, 2017, 03:16:36 PM »
Great!
dsk
Please notify me of dead links in my postings.

C*NET +1 999-3011


I have even got a regular New York number :-) 646 570 1796

unbeldi

  • Guest
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #8 on: March 07, 2017, 03:27:43 PM »
I suppose one could simply use a local battery induction coil and wire only the primary winding.  Afterall, this is the same configuration we are trying to achieve here.

Offline dsk

  • Hero Member
  • *****
  • Posts: 3182
Re: AE 40 local battery circuit of the type N-4078 desk set
« Reply #9 on: March 07, 2017, 03:39:43 PM »
As unbeldi states:  It needs to provide reasonably high impedance at voice frequencies though, so that the battery doesn't short the generated voice current.

About anything with relatively lo resistance combined with high ipedance will work!

dsk

Please notify me of dead links in my postings.

C*NET +1 999-3011


I have even got a regular New York number :-) 646 570 1796