N-717AHR questions...

[Lupo]

Hi folks,

Before I dive into this phone any further I thought I'd run the symptoms by the community here to see if it an "oh that, that's easy" problem.

Northern Electric N-717AHR (im pretty sure the R stands for Rotary as I have drawing for the N-717AH and it doesn't have a dial).  After I hooked up a new cord to L1 and L2 I get a dial tone on unhook, but no dial out, no ring and no answer.  After i click the hangup lever a couple of times I get the fast beep this phone is not in service and no one else can call my number until i disconnect the phone.  When I replace it, i get a dial tone again.

It does another odd thing...it rings when i crank it, even though i can see the decouple switch make.

I'm thinking condenser, but i will wait until i see what you guys think.  It's in really amazing shape and I don't want to take it all apart more unless i have to.

BTW, that Army manual really is great!!  Thanks for that tip.

[G-Man]

A few questions-

Is the designation N-717AHR printed or stamped into it? If so, does the "R" look like it was added by someone in the field?
Also, do you have a couple of "D" cells or equivalent connected for talk battery?
                     
Remember, most sets equipped with both a dial and magneto did not always used loop-dialing but composite signaling instead. In this case the dial is connected through the ringer coils to both sides of the line (tip/ring) through the dials black wire and to ground via the yellow wire, and the ringer does not have a condenser in its circuit.

I believe the applicable circuit diagram is in the TCI Library and I will try to retrieve it for you and add pertinent annotations to make it easier to follow.

Also, what is the Army Manual you are referring to? Does it have schematics for these sets?

[AE_Collector]

Welcome Lupo!

Lupo attached a wiring diagram from DavePEI that shows the battery supply connected but we will have to wait for his response to se if he has a battery connected or not.

Terry

[G-Man]

Take a look and see if your set is wired that same as the attached circuit diagram for a Northern Electric N717AP.

As you can see the ringer coils are bridged across the line without a condenser in series. One side of the dial pulsing contacts is connected to ground and the other is connected to the center-tap of the B1X ringer coils and thusly through the coil windings to both sides of the line (L1/L2).

If the circuit is different we will have to find the applicable diagram for your set.

[Lupo]

Hi Folks,

No, I don't have a battery connected currently. The model number is stenciled in in white paint, the "R" included.  I haven't had a chance yet to see if mine matches the drawing sent by G-Man.  Will check tonight. 

[DavePEI]

Hi Folks,

No, I don't have a battery connected currently. The model number is stenciled in in white paint, the "R" included.  I haven't had a chance yet to see if mine matches the drawing sent by G-Man.  Will check tonight. 

Sounds like the ringer is seizing the line - it needs a capacitor in series with it to prevent this...

Dave

[G-Man]

Hi Folks,

No, I don't have a battery connected currently. The model number is stenciled in in white paint, the "R" included.  I haven't had a chance yet to see if mine matches the drawing sent by G-Man.  Will check tonight. 

Sounds like the ringer is seizing the line - it needs a capacitor in series with it to prevent this...

Dave

That's a given but before we have him rewire the set it is important to make sure we have the proper wiring diagram. If the wiring in his set is similar to the one in this diagram he will also have to rewire the dial, etc.

[DavePEI]

Hi Folks,
No, I don't have a battery connected currently. The model number is stenciled in in white paint, the "R" included.  I haven't had a chance yet to see if mine matches the drawing sent by G-Man.  Will check tonight.  

Sounds like the ringer is seizing the line - it needs a capacitor in series with it to prevent this...
Dave

That's a given but before we have him rewire the set it is important to make sure we have the proper wiring diagram. If the wiring in his set is similar to the one in this diagram he will also have to rewire the dial, etc.

The most important thing is why destroy a perfectly good common battery set - it is better to find another magneto set and connect the two to each other and use them as intercoms. POTS phones can be bought for $5 in discount stores, but these are getting rare. Keep them as they are, or make a lamp out of them  

Dave

[Lupo]

Ok my bad, it is a N-717APM not AHR.  The wiring is almost exactly the same as the N-717AP except there is a push button switch beneath the hook.  The yellow wire in G-Mans diagram goes through this push button.  Otherwise identical.

[Lupo]

oh and to G-man: the army manual is the 1953 US Army Fundamentals of Telephony manual. 

http://www.oldphoneguy.net/images/FUNDAMENTALS-OF-TELEPHONY-200DPI.pdf

[dsk]

Hi folks,

Before I dive into this phone any further I thought I'd run the symptoms by the community here to see if it an "oh that, that's easy" problem.

Northern Electric N-717AHR (im pretty sure the R stands for Rotary as I have drawing for the N-717AH and it doesn't have a dial).  After I hooked up a new cord to L1 and L2 I get a dial tone on unhook, but no dial out, no ring and no answer.  After i click the hangup lever a couple of times I get the fast beep this phone is not in service and no one else can call my number until i disconnect the phone.  When I replace it, i get a dial tone again.

It does another odd thing...it rings when i crank it, even though i can see the decouple switch make.

I'm thinking condenser, but i will wait until i see what you guys think.  It's in really amazing shape and I don't want to take it all apart more unless i have to.

BTW, that Army manual really is great!!  Thanks for that tip.

This is how I would have tried to get it up an go:
Note the capacitor use: The Red/Black part in series with the receiver, just to stop DC.
The Battery still powers the transmitter.
The .6 mF capacitor isolates the ringer so you really can go off-hook. The smaller capacitor will probably limit the REN load also.
The DC path telling the exchange you are off-hook will go trough the induction coil and the resistors.
You may try what effect it will give by shorting the terminals A and C on the induction coil. This will probably be good for short lines.
The connection between Red from capacitor, and White from receiver could be done by screw and nut + tape, ore whatever connects those 2 wires, and protect them from connection to anything else.

dsk

PS! Yes if you keep the generator it will both ring your own ringer, and send current out to other things at the line as the exchange or other phones. The exchange may not like this, so its better to disconnect the generator.
DS

[Lupo]

The phone is actually wired like the diagram above for the N-717AP.  If just a little rewiring is all that's required as long as I give it battery power, I'd be happy with that.

[dsk]

The dial seems to be to a quite different system, the thread http://tinyurl.com/afslrfn with a diagram made med redesign that diagram to this:



In your diagram it seems like its only 2 wires to the dial, is that correct?

dsk

[G-Man]

Earlier I provided the correct diagram for this instrument but the wrong diagram is being referenced in this case.

First of all as is apparent in the correct diagram, this instrument does not use loop-dialing, instead it uses composite dialing with the dial connected to BOTH SIDES of the line through through the ringer coils, terminating to ground. Also, when the condenser is used in the transmission and ringing circuits the C.B. diagrams show them connected differently.

ISTR that this instrument has the option of being converted to conventional loop dialing with simple strapping options; without resorting to butchering the original wiring. As Dave said, it would be a shame to destroy a rare set when common battery instruments as so plentiful.

I will have to find the notes associated with the diagram however someone else maybe willing to share theirs with Lupo.

[dsk]

Lots of good arguments here.

I have made this test circuit, jut to use the phone as it is all changes are made on the line outside the phone.

The drawbacks  may be fixed later.

Whats needed is a capacitor 1-2.2 micro-Farad rated 200V or more. (just a typical ringer capacitor)

The circuit lets the dial work on a regular line, but the ringer may make sound when dialing, and you will probably have loud clicks in the receiver. (this may be fixed later)

You need to use a battery as in the original setup. any 3V battery should be OK

The polarity to the line will not be important if you don't have intentions of using this quite much, the best polarity is the polarity who makes the receiver membrane to be moved nearer to the permanent magnets.

The only 2 risks testing this will be if you try to dial when you have the receiver near your ear, this may really give loud clicks! or if you crank the phone the generated current may harm other equipment on the line!. Don't crank the phone!

dsk