Kjobenhavns Question

[bbuswell]

Greetings,

I've been learning from this forum for months now but this is my first post and question.  I recently added a 1944 kjobenhavns D-08 (I think) to my collection but I can't get it fully operational.  It did not come with a line cord so I took a guess at connecting, picture 1.  The phone rings, dials out, and the other party can hear me but I can't hear them.  I hear a super faint sound when the other party is speaking but I can't make it out.  When I go off hook I do not hear dial tone.  I don't know if I need a jumper somewhere or if possibly the ear piece is broken.  Can anyone tell me if this wired correctly?  I drive my rotary phones with a Panasonic PBX.  It appears the dial has been rewired with modern wire, but that seems to work fine.

Also what is the switch on the handset for, picture 2?  Seems I have to press it to speak but I'm not sure.

Thanks
Brett

[unbeldi]

? Have you compared your wiring with this topic already:  http://www.classicrotaryphones.com/forum/index.php?topic=4640.0


From that thread, this diagram shows the push button too, I believe, although it is not the exactly fitting diagram, since it contains a generator.  It is a local battery magneto phone.

[bbuswell]

I've study the diagram posted by bingster but it shows a 4 wire line cord.  I'm only working with a single pair.  How does the unused pair get looped in if it is required?

[unbeldi]

I've study the diagram posted by bingster but it shows a 4 wire line cord.  I'm only working with a single pair.  How does the unused pair get looped in if it is required?

Obviously, a four conductor line cord makes little sense, I agree. You only should need two.  The diagram and post does not explain its function, and there is no circuit diagram for that wiring.  I would have to spend some time drawing a functional, and comprehensible circuit diagram.

But, two of the line cord conductors are shunted, so it is only three.  Without redrawing the actual circuit of that diagram, I suspect the third is a function for an external bell.

[Alex G. Bell]

Obviously, a four conductor line cord makes little sense, I agree. You only should need two.  The diagram and post does not explain its function, and there is no circuit diagram for that wiring.
But, two of the line cord conductors are shunted, so it is only three.  Without redrawing the actual circuit of that diagram, I suspect the third is a function for an external bell.

The circuit diagram shows a LB circuit.  I'd think the 2 additional conductors would be for an external battery supply since I doubt it fit inside the body of the phone. 

The diagram seems to be more of a schematic than an actual wiring diagram, accurately showing cord conductors.

[unbeldi]

The circuit diagram shows a LB circuit.  I'd think the 2 additional conductors would be for an external battery supply since I doubt it fit inside the body of the phone. 

The diagram seems to be more of a schematic than an actual wiring diagram, accurately showing cord conductors.

Ah that makes sense.  I did not trace anything in that diagram other than the cord attachment.   Many of there were indeed LB sets.
But the set has a dial.  So it must at least be CB signaling.

[unbeldi]

Are we now talking about the same diagram:


This is Bingster's

[Alex G. Bell]

Are we now talking about the same diagram:


This is Bingster's

No, I was talking about the diagram you posted in Reply #2.

[unbeldi]

No, I was talking about the diagram you posted in Reply #2.

Yes, I already had stated it was a local battery diagram.

[Alex G. Bell]

Yes, I already had stated it was a local battery diagram.

Fair enough.  Did not follow it closely.

Before getting down to an accurate circuit diagram, which might be very time consuming, perhaps it's best to investigate without that whether the receiver has a diaphragm, whether it has an air gap to the pole pieces, and proper operation of the dial ON contacts and cradle switch contacts. 

Perhaps as a starting point putting a 1½V dry cell across the receiver leads in the phone to see whether there is a loud click.  This would prove whether the receiver itself and handset cord are intact.

[Alex G. Bell]

Yes, I already had stated it was a local battery diagram.

Well sort of.  You also said: "It is a local battery magneto phone." when apparently you meant that it is a LB magneto phone diagram.  So I've been proceeding thinking it was a LB phone, hence my comment about 2 cond's. for the battery supply.

[bbuswell]

Thanks Alex.  I was able to hookup another earpiece and it sounds great.  Apparently the wiring is correct and my issues lies with the speaker.  I'm trying to take the handset apart but I haven't figured out the trick yet.  Do you think the speaker repairable?

[Alex G. Bell]

Thanks Alex.  I was able to hookup another earpiece and it sounds great.  Apparently the wiring is correct and my issues lies with the speaker.  I'm trying to take the handset apart but I haven't figured out the trick yet.  Do you think the speaker repairable?

You're welcome.  Yes, connecting an alternate receiver is another way to get at the same problem.  Good thinking.  I did not know what you had on hand so I assumed the simplest: a cell.

IMO, since you do hear some sound, the coils of the receiver are probably not open (broken) but could be short circuited.  But first I would look for mechanical problems.  Doesn't the receiver cap unscrew?  Since the photo only shows the handle I don't know what the receiver end looks like but have never seen a receiver cap of this vintage that did not unscrew. 

There needs to be a metal "diaphragm" disk under the cap and an air gap between the diaphragm and the pole piece or pieces of the electromagnets beneath it.  Sometimes the diaphragm is badly bent or dented or a paper ring of the same diameter as the diaphragm which spaced it away from the pole piece(s) is missing.  If it touches the pole pieces receiving can be very weak.

[bbuswell]

I have a broken ericofon and was able to wire the speaker to the terminals.  Attached are some pics of the receiver.  It has two screws on the back that came out but nothing will budge.  I fear I'm going to break it, at least the bakelite, and it's not like the sell just the receivers on eBay.  Does anyone know of a trick or where this thing separates?

[Alex G. Bell]

You should not be removing the receiver from the handle.  The connections are inside, under the Bakelite cap, behind the diaphragm.  You need to unscrew the Bakelite cap to inspect it, as explained previously.  You will see the terminals and be able to disconnect it but there is no indication so far that you need to disconnect it.