Author Topic: Schematic for QNB18B Northern Telecom Network  (Read 2764 times)

Offline phonenovice

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Schematic for QNB18B Northern Telecom Network
« on: June 17, 2015, 11:15:21 AM »
Hi Everyone
Just wondering if anyone out there has or know where to get the schematic for telephone network QNB18B?
Thanks in advance!
« Last Edit: March 06, 2016, 06:50:32 PM by AE_Collector »

unbeldi

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Re: Schematic for QNB18B
« Reply #1 on: June 17, 2015, 11:32:05 AM »
Hi Everyone
Just wondering if anyone out there has or know where to get the schematic for telephone network QNB18B?
Thanks in advance!

Here it is from the Northern Telecom card catalog.

The base variety is the A-suffix version. The B-suffix version is described as having two additional terminals for use in the QSK10 antique sets.
« Last Edit: June 17, 2015, 11:36:05 AM by unbeldi »

Offline paul-f

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Re: Schematic for QNB18B
« Reply #2 on: June 17, 2015, 06:52:10 PM »
Was the card catalog page from the TCI Library?
 
   http://www.telephonecollectors.info/doc/NEC0_Catalog_Cards/N/NETWORKS.PDF
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unbeldi

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Re: Schematic for QNB18B
« Reply #3 on: June 19, 2015, 12:24:22 PM »
Was the card catalog page from the TCI Library?
 
   http://www.telephonecollectors.info/doc/NEC0_Catalog_Cards/N/NETWORKS.PDF

Yes, that was the source of the PDF files.

Offline phonenovice

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Re: Schematic for QNB18B
« Reply #4 on: June 20, 2015, 03:52:43 PM »
Thanks for your replies. Here is a picture of the phone with the network QNB18B. Actually; what I need is help with the wiring diagram. The phone originally worked but not the ringer, and when I do some switching of the connections, I get the ringer to work but no hearing of a voice. Can anyone help with this problem? Thanks.

Offline Ktownphoneco

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Re: Schematic for QNB18B
« Reply #5 on: June 20, 2015, 04:33:04 PM »
What is the catalog code number of the actual telephone set ?     It should be on the bottom of the set.

Jeff Lamb

Offline phonenovice

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Re: Schematic for QNB18B
« Reply #6 on: June 20, 2015, 04:41:21 PM »
The information at the bottom of the telephone says, " This housing conforms to drawing B-696501, F-56660 (Gold) or 581A Telephone set 6U Dial New York Telephone Company  NO. 205-ZL2-58   CONTESSA-US-5    Ser. NO. 10009"

Offline NorthernElectric

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Re: Schematic for QNB18B
« Reply #7 on: June 20, 2015, 05:05:26 PM »
The information at the bottom of the telephone says, " This housing conforms to drawing B-696501, F-56660 (Gold) or 581A Telephone set 6U Dial New York Telephone Company  NO. 205-ZL2-58   CONTESSA-US-5    Ser. NO. 10009"

There is an installation manual for a phone that might match the labelling on the base of your phone here.  These were one of those phones where the consumer bought the housing and the installer came and put the internal parts in.  BUT, the internal parts shown in this document don't seem to match what you have in your phone, and in fact it appears to be using Automatic Electric parts.  I wonder if yours is a Canadian version using Canadian parts?

If you made a note of how it was originally wired and can put it back that way so that everything works except for the ringer, then maybe this diagram will help you get the ringer working.  This diagram is for a Contempra touch tone (with a QNB18A network) so don't even look at the handset connections on this, just how the the ringer is connected.  If you don't have terminals marked L1 and L2, assume that L1 and L2 are where the green and red line wires were connected to.
« Last Edit: June 20, 2015, 05:16:39 PM by NorthernElectric »
Cliff

unbeldi

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Re: Schematic for QNB18B
« Reply #8 on: June 20, 2015, 06:42:40 PM »
These phones should be wired essentially like a 500-type telephone. The network is equivalent to the 425B.

The ringer is wired between L1 and L2 in series with the ringing capacitor on terminals A and K:

(L1)-----------ringer----(A)--||--(K)--------(L2)

If your ringer has four wires then you can place the capacitor between the center wires by connecting them to (A) and (K).

PS:   I believe your telephone has an M1A type ringer.  That ringer type has four wires too, but they are just taps on one coil.  This means that you only need to connect the red and black wires (start and end of coil).  So:
        (L1)----black---M1A ringer----red----(K)---||---(A)-----(L1)
« Last Edit: June 20, 2015, 07:22:57 PM by unbeldi »

Offline poplar1

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Re: Schematic for QNB18B
« Reply #9 on: June 20, 2015, 08:06:20 PM »
9 times out of 10, the problem can be solved by moving the black ringer wire from G to L1. Leave the line cord connected red to L2 and green to L1.

This phone more than likely originally had a non-modular cord, and the green wire from L1 and the yellow wire from G were connected together at the wall connecting block. So, when a spade-to-modular cord is added, which makes the phone "quarter modular", it is necessary either to move the ringer wire, or strap the G and L1 terminals together inside the set. It's usually easier to move the ringer wire.

No doubt, if you got it to ring but then couldn't hear dial tone, it was because you had temporarily connected the line to L2 and G, which is where the ringer circuit would have originally connected. When you first got the phone, and had the line connected to L1 and L2, and the black ringer wire on G, then you had dial tone, but the phone didn't ring.
"C'est pas une restauration, c'est une rénovation."--François Martin.