Author Topic: READABLE diagram for Northern Electric 3 slot push button payphone.  (Read 1154 times)

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #15 on: July 14, 2017, 06:17:41 PM »
I picked up a W.E. 2500 at my local Habitat for Humanity ReStore two weeks ago for $3.00.  The 2500 worked just fine.  The pad is a 72H3A dated 3-82.  Red, Green, Blue, White, Black, Orange/Black, Red/Grey, and White/Blue wires.  Even with the old pad from 1968 and trying 2 different hand sets, volume was very weak.  I swear I was able to get the 1982 pad to dial!  Plus, the diagram doesn't show what to do with the green and black wires.  And of course I tried swapping line wires for polarity.

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #16 on: July 14, 2017, 06:21:16 PM »
White/Blue was taped off.  I thought it was a substitute for Orange/Red.

Offline Stan S

  • ****
  • Posts: 327
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #17 on: July 14, 2017, 06:52:34 PM »
A Western Electric type 72 Touch Tone dial is an integrated circuit pad. What was originally in your 2236 was a pot core pad. The colors of the leads coming out of the pad are different. Get a pot core dial.
Stan S.

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #18 on: July 14, 2017, 07:27:29 PM »
I have a few lying around but I think they need tuning.  I'm on the road at the moment, but the original dial was dated 1968.

Alex G. Bell

  • Guest
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #19 on: July 14, 2017, 07:28:14 PM »
A Western Electric type 72 Touch Tone dial is an integrated circuit pad. What was originally in your 2236 was a pot core pad. The colors of the leads coming out of the pad are different. Get a pot core dial.
Stan S.
Even a pot core dial will probably not work just by matching lead colors because the original dial used the BL to feed the common R terminal of the NET to the receiver for switching inside the dial via the W lead, like early 7-lead  dials.  Most dials have 8 leads and switch the receiver via an isolated circuit consisting of W & W-BL.  Most likely the BL and W-BL leads of the dial will have to connect to R of the NET via the #10 terminal for the receiver to work.

Alex G. Bell

  • Guest
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #20 on: July 14, 2017, 07:32:30 PM »
I picked up a W.E. 2500 at my local Habitat for Humanity ReStore two weeks ago for $3.00.  The 2500 worked just fine.  The pad is a 72H3A dated 3-82.  Red, Green, Blue, White, Black, Orange/Black, Red/Grey, and White/Blue wires.  Even with the old pad from 1968 and trying 2 different hand sets, volume was very weak.  I swear I was able to get the 1982 pad to dial!  Plus, the diagram doesn't show what to do with the green and black wires.  And of course I tried swapping line wires for polarity.
You cannot just assume that dials are interchangeable, especially if there are different lead colors, even if it worked in a different environment.  Even leads of the same colors may not function the same. 

IIRC, 72H3A dials contain a polarity guard. 

Dates are pretty much irrelevant.  Apparatus ID codes are all that matters.

Alex G. Bell

  • Guest
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #21 on: July 14, 2017, 07:35:29 PM »
White/Blue was taped off.  I thought it was a substitute for Orange/Red.
No, W-BL is the input signal from the network to the receiver via the dial.  You cannot possibly hear anything in the receiver with the W-BL lead unconnected.

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #22 on: July 14, 2017, 10:39:48 PM »
I wonder why they kept the same wire colors but changed their function between pad models?  Did anybody every make a chart that cross references tt pad model numbers and wire functions?

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #23 on: July 14, 2017, 10:48:56 PM »
Anywhoo, incorrect pad and/or wiring aside, with the pad completely removed from the network and the DA15 wired per the correct diagram, I can barely hear the dial tone on this network, even after trying several handsets that sound fine on other phones.  I am half tempted to use both the dial AND network from the ReStore 2500 and put this issue to bed.  I didn't pay that much for this payphone and it's tough to expect every piece of 50 year old technology to work like it did from the factory.  Any other thoughts before I shoot this lame horse?

Alex G. Bell

  • Guest
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #24 on: July 14, 2017, 10:50:58 PM »
I wonder why they kept the same wire colors but changed their function between pad models?  Did anybody every make a chart that cross references tt pad model numbers and wire functions?
It's just not that simple.  A telephone circuit is complex and a TT dial can be inserted into the circuit a number of different ways.  So cross referencing the leads assumes all phones have the same circuit.  They don't.

Alex G. Bell

  • Guest
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #25 on: July 14, 2017, 10:52:47 PM »
Anywhoo, incorrect pad and/or wiring aside, with the pad completely removed from the network and the DA15 wired per the correct diagram, I can barely hear the dial tone on this network, even after trying several handsets that sound fine on other phones.  I am half tempted to use both the dial AND network from the ReStore 2500 and put this issue to bed.  I didn't pay that much for this payphone and it's tough to expect every piece of 50 year old technology to work like it did from the factory.  Any other thoughts before I shoot this lame horse?
As I said before, the receiver (and the transmitter) circuits pass through the dial.  With the dial disconnected those circuits are open so I'm surprised you hear anything at all!

Offline Stan S

  • ****
  • Posts: 327
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #26 on: July 14, 2017, 10:55:03 PM »
The answer to your question is yes.
All the information regarding TT pads is in the TCI library. You just have to do the research.

The info below is courtesy of some very hard working TCI members.
Stan S.

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #27 on: February 01, 2018, 08:55:42 AM »
I purchased yet another 2500 from an antique store for 5 bucks and am attempting to use its pad and network in my NE-2236QC.  The pad is wired correctly, I get tone, and am able to dial.  However, I cannot hang up nor can I receive calls at this point.  I think it's an issue with the hook switch.  The 2500 had 6 wires to the hook switch and I am assuming that's three pairs of wires that connect to the network.  I need to know which wires from the NE2336 hook switch connections (R, BB, W, Y, SL, BBX, GN) connect to the 4228 Network's connections (L1, G, A, C, S, R) to make this work as a house phone.  Several parts in the lower housing are missing, and, yes, I am aware that I listed 7 connections in the hook switch for 6 connections on the network.

Offline poplar1

  • Hero Member
  • *****
  • Posts: 5772
  • 102C-6 = "Old Brass" Hand Telephone Set
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #28 on: February 01, 2018, 10:58:29 AM »
On a network such as the 4228, the only significant terminals for the talk path are as follows:

C and RR are the input
GN is the output for receiver, B is the output for transmitter, and R is the output for common transmitter/receiver.

A and K are for the capacitor in the ringing circuit

L1, L2, G, S, and T are blind terminals -- just a place to connect wires. F is a blind terminal in a WE 2500 and for the dial filter in a rotary phone.

Are you trying to connect this network to the 2236 per the original 2236 diagram, or just rewire the payphone like a 2500?
Per the original schematic, none of the hookswitch wires connects directly to the network.
There are two sets of hookswitch contact springs in the payphone: Y and SL disconnect the line. GN and BBX disconnect the receiver.

The line connects to L (terminal strip) and Y on hookswitch. Opening the Y-SL contacts should disconnect the line when you hang up.
« Last Edit: February 01, 2018, 11:13:53 AM by poplar1 »
"C'est pas une restauration, c'est une rénovation."--François Martin.

Offline tanderson78

  • *
  • Posts: 32
Re: READABLE diagram for Northern Electric 3 slot push button payphone.
« Reply #29 on: February 05, 2018, 11:08:54 PM »
I guess the answer to the question is "both", sort of.  I want to use the DB15 wiring harness to connect the 2500's network and pad in the upper housing to the lower housing.  I am by no means an expert so I don't know how I should connect to hook switch to the pad properly.