News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

Northern Telecom AG Plane ringer not working

Started by mfs, May 27, 2022, 10:25:50 PM

Previous topic - Next topic

mfs

Hi,

I just got my hand on a Alexander Graham Plane phone and hooked it up to an ATA. It is mostly working fine but just won't ring. ATA is a PAP2T set to sinusoid waveform for ringing.
I suspect there is something wrong with the wiring but I have no real idea where to even start (my analogue phone skill are a bit rusty).
Anyone can point me in the right direction to fix this?
1.jpg
3.jpg


--Martin 

paul-f

Welcome to the forum, mfs.

A good starting point is the practice for the set. It can be found in the TCI Library using this search link:
https://www.telephonecollectors.info/index.php/search?q=alexander+graham+plane+may78

That should help you trace the wiring to verify whether it is correct.

But first, do other phones with similar ringers work on your ATA?

Also, there is a small chance that the ringer in your set is a frequency ringer. I have run across a few in AGP sets in the past, and replaced them with straight line ringers. Check the model number of the ringer with the one in the practice.
Visit: paul-f.com         WE  500  Design_Line

.

mfs

Hello Paul,

thanks for pointing me to the schematic. Still a bit lost but it helps.

Quote from: paul-f on May 28, 2022, 10:36:33 AMWelcome to the forum, mfs.

A good starting point is the practice for the set. It can be found in the TCI Library using this search link:
https://www.telephonecollectors.info/index.php/search?q=alexander+graham+plane+may78

That should help you trace the wiring to verify whether it is correct.
I tried to do that.
If I read the right, then the ringer should normally be connected to K by red wire (that is the case) and to G by black wire on the network. In my wiring it seems to go to L1. Also AUX should not be connected but goes to X. Both X and Y should be empty If I understand this correctly.
Further down, everything seems to be wired according to the schematic.
4.jpg
N.E. Alex. Graham Plane Tel. Set - S.jpg
But given Table C, L1 might be correct (assuming I have a NE-D4QH cord, no idea. But if I assume it to be wired to work that'd be the case).
TableC.jpg
Which leaves AUX going to X, but according to the schematic X is dead, so it seems correct to me.


Quote from: paul-f on May 28, 2022, 10:36:33 AMBut first, do other phones with similar ringers work on your ATA?
Actually no idea. Unfortunately I don't have any other (vintage or otherwise) phone even close I could try (I can say the integrated fax of my printer works, at least as well as any fax over voip. Doesn't help though).

These are the specs:
ATASpec.jpg
At the moment I would guess the issue lies with the ATA. It's set to 85V/sinusoid/20Hz.
I have no idea on to verify or fix it, if thats needed.

Quote from: paul-f on May 28, 2022, 10:36:33 AMAlso, there is a small chance that the ringer in your set is a frequency ringer. I have run across a few in AGP sets in the past, and replaced them with straight line ringers. Check the model number of the ringer with the one in the practice.
One of the screws holding seems to be worn out a bit, so I can't really remove it without risking some damage it seems. So I don't know unfortunately. Any other way to distinguish them?


--Martin

mfs

I just put a Multimeter to the ringer I see around 90V on the ringer when ringing (or rather when its supposed to ring). So I guess either the ATA not powerful enough, frequency ringer or simply broken.

Still trying to get it out without breaking things though...

paul-f

Quote from: mfs on May 29, 2022, 04:04:17 AMSo I guess either the ATA not powerful enough, frequency ringer or simply broken.
It's been a long time since I've worked on an AGP, and I don't recall any obvious visual differences between frequency and SL ringers used in this model. Perhaps other forum members can help with details.

Since you have a multimeter, you can disconnect the ringer and check for coil resistance (not an open or short circuit).

A friend or family member with known working wired phone service might let you test your phone on their line.

Absent other test equipment, you might find a vintage phone at a yard sale or thrift store for little money, or borrow one for some tests. It can be used to provide other data points, such as another test of the ATA's ringing capability. If it rings, you can temporarily swap ringers and see if the non-ringing stays with the ringer or the phone.

Visit: paul-f.com         WE  500  Design_Line

.

mfs

Quote from: paul-f on May 29, 2022, 01:00:22 PMIt's been a long time since I've worked on an AGP, and I don't recall any obvious visual differences between frequency and SL ringers used in this model. Perhaps other forum members can help with details.

Since you have a multimeter, you can disconnect the ringer and check for coil resistance (not an open or short circuit).
Did that and it seems good to me. I get 5.8k in total, the 1k is there, the 1.65k reads as 1.5something but thats expected tolerance.
The unmarked I get as 3.25k, not really sure about that, but not something unexpected.


Quote from: paul-f on May 29, 2022, 01:00:22 PMA friend or family member with known working wired phone service might let you test your phone on their line.

Absent other test equipment, you might find a vintage phone at a yard sale or thrift store for little money, or borrow one for some tests. It can be used to provide other data points, such as another test of the ATA's ringing capability. If it rings, you can temporarily swap ringers and see if the non-ringing stays with the ringer or the phone.
Here (Japan) best I could do is get another ATA, if I can find one even. Anything else (including a 'real' phone line) is pure luck...
I leaning towards the ATA at the moment, although I'd expect it to behave differently (as in crashing) if the ringer draws too much power.

mfs

I just got it to ring :D

I moved the tension spring to basically support the ringing (opposite of "normal") and now it is ringing, albeit fairly weekly.
So I guess the ATAs (both of them) are just to week to properly ring... I guess I have to look into amplifiers.