Author Topic: Looking for help with a 1969 Northern Electric 3 slot touch tone payphone  (Read 2505 times)

Offline rglenn

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Well, I know the dial works but I could use some guidance on the wiring.  The Dial it is replacing (NE35E3) has 8 wires of which 7 were connected to either the terminal or network.  The new dial (NT3503L2) has 4 wires (the directions describe 6 with 1 not used)

Offline rglenn

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Ok, I got the dial installed and through process of elimination, got it to dial.  Currently everything is working except the transmitter.  The pay phone caller can hear the called party but the called party can not hear the pay phone caller.  I could have the dial wired wrong.  I also found some information on post pay phones indicating the transmitter is intentionally shorted until coins are deposited.  Depositing coins doesn't enable the transmitter.

Suggestions welcomed.

Offline Key2871

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Check the handset by connecting it up to another phone, to eliminate or confirm that the transmitter is working.
I don't see how the dial would have any bearing on the transmitter not working. You can try reversing the transmitter wires on the network, but I again don't think that would effect the transmitter.
And connect a known working handset and try that.
KEN

Offline rglenn

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Ok, thanks.

Offline Key2871

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On some of these sets, the transmitter was muted unless the hopper was triggered by a coin. It could be what's happening with yours. So if you try another handset and the problem persists, trigger the hopper switch with your finger go from there.
Also, hot water an a strap wrench will work to get the handset caps off. That's what I had to do with my Northern.
KEN

Offline rglenn

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Well, I tried another handset, same issue.  Then I tried your finger on the hopper idea and as I depress it, I can hear the audio from the called party but for only a moment.  Holding it all the way down doesn't maintain the audio.  I have to catch it just right but am able to reproduce it almost every time.  I feel like I'm getting close but am not sure what to do to bypass this switch/connection?

Offline rdelius

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Have you tried reversing the polarity of the line cord (Red and Green)?

Offline rglenn

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Yes, no change.  I thought it would stop the dial from working but didn't.

Offline Key2871

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What's that picture of? I've not seen anything like that before.
KEN

Offline rglenn

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Here is a wider shot.  The blue arrow is what I am pressing down to get the audio to work briefly.

Offline rglenn

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I assumed that was the hopper switch you mentioned.

Offline Key2871

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That must be a post pay set up. I've never seen that before.
So there must be something that triggers when the coin passes, that's not triggering to allow voice.
Since I've never seen that setup I don't know what to say. There must be someone here who knows about northern post pay set up?
KEN

Offline HarrySmith

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  • Posts: 6817
  • 1937 302
Can you pull that part out & get a picture of the other side that shows the wiring? Looks like ony 1 screw holds it in?
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

Offline rglenn

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  • Posts: 43
I'll take a look and post a pic shortly - thanks!

Offline rglenn

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Appears to be held on by 3 screws.  I can remove if helpful but I think I got Pics of all the wiring.