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Rewiring a Coquette

Started by mblythe, July 14, 2017, 07:24:35 PM

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mblythe

Hi, I have a 1974 Coquette telephone, with no maker mark that I can find other than "Made in Korea". It came with the original hard-wired line cord clipped, so I'm trying to put a new cord on it. The remaining tail of the original 3-lead cord was connected as follows:

G => L1
R => L2
Y => E (?)

The terminals on this phone are marked very differently from most I've seen. From left to right, the labels read:

L1  E  L2  L  T  RT  R

I hooked the new cord up the same way as the original, but do not get a dial tone. I did find one wiring diagram for the Coquette, but it did not seem to match what I'm seeing in this one.

I'd appreciate any suggestions you might have.

Thanks!

Alex G. Bell

Quote from: mblythe on July 14, 2017, 07:24:35 PM
Hi, I have a 1974 Coquette telephone, with no maker mark that I can find other than "Made in Korea". It came with the original hard-wired line cord clipped, so I'm trying to put a new cord on it. The remaining tail of the original 3-lead cord was connected as follows:

G => L1
R => L2
Y => E (?)

The terminals on this phone are marked very differently from most I've seen. From left to right, the labels read:

L1  E  L2  L  T  RT  R

I hooked the new cord up the same way as the original, but do not get a dial tone. I did find one wiring diagram for the Coquette, but it did not seem to match what I'm seeing in this one.

I'd appreciate any suggestions you might have.

Thanks!
There are basically 2 ways to troubleshoot a phone: by prescription or by logical deduction.

Prescription works for phones people are familiar with.  Little overview information about the phone is needed since the phone is well known.

Logical deduction is required for unknown phones.  It depends on figuring out the phone circuit from photos or other information you provide.  This requires complete internal views of the phone, not limited partial views of terminal strips where the terminal designations are not visible. 

I suggest you post much more complete photos.  Otherwise unless someone happens to know this phone I doubt anyone will be able to help except by trial and error, which is slow and tedious and only succeeds by good luck, which is unlikely.

I can tell you that L-5C is the standard Japanese induction coil used in their equiv. of the 302, perhaps made by a Japanese mfr, their Korean subsidiary or an independent Korean mfr.  OPC is the mfr's ID, not one I recognize but the classic way Japanese mfrs identify their products: 3 letters in a geometric outline, often a diamond. 

If you find a circuit diagram for a Japanese #5 telephone set it might well match this telephone.

You say you did not get dial tone but you have not told us whether the phone seizes the line.  Take another phone off hook at the same time and see whether you can hear what is said into the Coquette in the other phone and dialing sounds.  Call it and see if it rings.

You list the terminals from L->R but they are vertical in the photo.

unbeldi

The Made in..  mark tells the story.

It is a copy with an Asian circuit.   I bet the circuit is similar to the DO-8 found on many Japanese creations.
If it were the genuine US product, it would be marked 882A200 or so.

L1 -  Line 1
E  - Extension bell
L2 - Line 2
L - ground
T, TR, R  - handset connections: transmitter, common, receiver

Please compare this diagram with the wiring in your set.

mblythe

unbeldi: thanks for the diagram. From what I can see, I don't think it's a complete match to this phone. Wire colors are definitely different in most cases, and where they connect seems hit and miss as well. For example, the spiral handset cord on this phone connects:

BK => T
R+W => RT
W2 => R (a second white)

I may be misreading the diagram though, since I'm not clear what all the abbreviations are.

Here's a labeled photo of the terminals from my phone, so there's no confusion about left, right, top, bottom.

mblythe

As AGB requested, full internal shots from a variety of angles.

unbeldi

#5
Certainly, wire colors will be different, and your set may not have the exact same switch arrangements.  But that is really not important.
What is important is that you understand the circuit principle and then the rest doesn't matter anymore.  Well, it matters, but would be pretty clear.


Quote from: mblythe on July 14, 2017, 08:32:54 PM
unbeldi: thanks for the diagram. From what I can see, I don't think it's a complete match to this phone. Wire colors are definitely different in most cases, and where they connect seems hit and miss as well. For example, the spiral handset cord on this phone connects:

BK => T
R+W => RT
W2 => R (a second white)

That seems to be exactly what I and the diagram described.   R+W are the return from the transmitter and the receiver, tied together as a common return.
In older telephones they would just run a single wire from the handset.


mblythe

So then in theory, to attach a new line with RJ11 jack on the wall end and paddle connectors on the leads, should it just go:

G => L1
R => L2
Y+BK -> insulate

This is what I tried initially with no luck.

To AGB's other questions, the phone does not ring with called nor pick up the line when answered. I don't have the ability to hook up two phones simultaneously, but I assume it would answer an incoming call if it was seizing the line.

Alex G. Bell

Quote from: mblythe on July 14, 2017, 08:50:53 PM
So then in theory, to attach a new line with RJ11 jack on the wall end and paddle connectors on the leads, should it just go:

G => L1
R => L2
Y+BK -> insulate

This is what I tried initially with no luck.

To AGB's other questions, the phone does not ring with called nor pick up the line when answered. I don't have the ability to hook up two phones simultaneously, but I assume it would answer an incoming call if it was seizing the line.
E must be jumpered to L2 for it to ring.  This is basic and so little of the phone is needed to work for it to ring that my guess is that the fact that it does not ring is unrelated to being unable to talk and listen.  The setting of the VOL control might also affect whether it rings at all once the jumper is in place.

Are you calling it with a cellphone?  When you try to answer do you hear anything at all in the receiver?  Are you using a landline, a cable modem or what is the source of your dial tone?

In this phone, if the transmitter circuit is open it will not seize the line and you would hear nothing when attempting an OG call but would hear ringing in the receiver even if the ringer did not ring.

mblythe

I have it hooked up via an OBI-100 VoIP adapter. I've tested the setup with another phone, just to make sure the OBI hasn't suddenly stopped working, and it tested fine. I'm calling it with a mobile phone.

I just tried again, and this time after answering on the Coquette, I did hear a quiet buzzing sort of ring in the earpiece. My mobile phone didn't seem to think the call had been answered, but I could hear the buzz-ring a couple of times before the call timed out.

Alex G. Bell

Quote from: mblythe on July 14, 2017, 09:07:21 PM
I have it hooked up via an OBI-100 VoIP adapter. I've tested the setup with another phone, just to make sure the OBI hasn't suddenly stopped working, and it tested fine. I'm calling it with a mobile phone.

I just tried again, and this time after answering on the Coquette, I did hear a quiet buzzing sort of ring in the earpiece. My mobile phone didn't seem to think the call had been answered, but I could hear the buzz-ring a couple of times before the call timed out.
It actually was not answered because unless the transmitter circuit is intact, which it seems not to be, it does not seize the line either to make or answer calls.  Ringing (a purring sound in the receiver) is not an indication of answering.

I strongly suggest you spring for a "T" adapter so you can plug 2 phones into the OBI at a time as this will facilitate troubleshooting.

Was this done with a jumper from E to L2 or not?

mblythe

No, I have not tried a jumper yet. I may have an old T adapter around here somewhere, I'll check.

For arguments sake, if the transmitter circuit is not intact, does that mean a capacitor needs replacing?

Alex G. Bell

Quote from: mblythe on July 14, 2017, 09:24:09 PM
No, I have not tried a jumper yet. I may have an old T adapter around here somewhere, I'll check.

For arguments sake, if the transmitter circuit is not intact, does that mean a capacitor needs replacing?
Nothing to do with the capacitor.  If the ringer works that would prove that one of the two capacitor sections was good. 

Transmitter circuit being open could be the result of one of the spring contacts under the transmitter unit being pressed down too far and not touching the contact on the back of the transmitter unit.  It could also be the handset cord.  Inspect the contacts first and bend them up slightly if there is any uncertainty about whether they are touching to back of the transmitter.

mblythe

So adding a jumper from E -> L2 seems to have solved all of the functionality. I now get a dial tone when I lift the receiver, it rings when called, and I can answer and converse. The sound is rather faint, and there is a lot of noise even just at the dial tone, but it's progress! Possible the noise was due to a makeshift jumper. Will try again with a short wire and see how it goes. Suggestions for a quality jumper material?

Thanks for all the help.

Alex G. Bell

Quote from: mblythe on July 14, 2017, 09:55:36 PM
So adding a jumper from E -> L2 seems to have solved all of the functionality. I now get a dial tone when I lift the receiver, it rings when called, and I can answer and converse. The sound is rather faint, and there is a lot of noise even just at the dial tone, but it's progress! Possible the noise was due to a makeshift jumper. Will try again with a short wire and see how it goes. Suggestions for a quality jumper material?

Thanks for all the help.
I don't see how jumpering E to L2 could cause other things to start to work unless some leads are swapped on the internal ("factory") side of the terminal strip or the designations are being misinterpreted and you were connecting the incoming line to the wrong terminals.  Does not make sense.

Any short piece of wire that's thick enough to handle and strip insulation from the ends of will work the same.  A scrap of 24 gauge wire would be typical.  Even a scrap of paper clip would work.

If there is noise (static, random scratchy noise I assume) that could be due to the transmitter needing replacement or a screw connection that's quite loose.  There are other possible causes but these are the first to check.

If you're going to work on phones you need at least a couple of alligator clip leads.  If you had a clip lead I'd suggest removing the transmitter from the handset and jumpering the two springs which touch its back.  If the static persists it's not the transmitter.  If it stops it is.

mblythe

I do have alligator leads, that's what I used for the jumper. I'll try jumping the transmitter contacts and see how it goes.