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Need advice for Kellogg Masterphone 700A

Started by DARK FATHER, October 07, 2011, 06:46:46 AM

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DARK FATHER

I just bought a black Kellogg Masterphone 700A off Ebay for $26.  It has no ringer box and I will likely need to put a mini-network in it like I did my WE 202 to get it to receive calls properly (no dial).  Is this indeed the case for a no dial phone like this?  I seem to remember reading this somewhere on here a year or so ago. 

GG



What to do about phones with no network components:

IF the receiver is a DC receiver (it will not have any permanent magnet in it, you can test this with a non-magnetic screwdriver), then you can wire the transmitter and receiver in series and that takes care of that.

IF the receiver is an AC receiver (the vast majority of receivers in handsets, since forever-ago), then you have three options:

One, the correct thing to do, get a subset.

Two, the more usual thing to do, get an AE Styleline mini-network.  This is the simplest way to get a phone like this operational, because these mini networks are as common as squirrels, and inexpensive, and easy to use (schematics widely available).  Some folks here do not like mini-networks because they're non-original components in antique phones; if that includes you, then you can consider it a temporary expedient on the way to a Kellogg subset.

Three, build a resistor/capacitor network:  Typically a resistor in series with the transmitter to drop the transmitter current flow to about 30 - 50 milliamps DC when off-hook, and a capacitor in series with the receiver to pass AC (audio) to it, and a dual-diode assembly across the receiver terminals in the phone to block acoustic shocks to the receiver.  There are schematics around that show various types of R/C networks for antique phone restoration. 

You definitely do NOT want to run DC through an AC receiver (one with a permanent magnet, basically any receiver found in a handset), because over time, it will demagnetize the magnet and cause the audio volume to decrease noticeably. 

There are various ways to wire up touchtone dials to telephone lines, to enable making nondial phones functional.  Or you could wait until voice recognition has become universal, when you can order a phone line from the telco that goes to a voice recognition system, and then you won't need a touchtone dial or a rotary dial: you can use all your nondial phones with their dial blanks (too bad it doesn't go off hook to "Number, please?":-)    (OTOH, voice recognition could become a pervasive and highly obnoxious form of surveillance.  I'd sooner do without it.)

If you want to wire up a touchtone dial, the simplest thing might be to use a 2500 base assembly as the network interface for the dial and the Kellogg 700 phone, or the network block from same in conjunction with the dial etc.  In that case you will need a 6-conductor cord from the Kellogg to the 2500 base assembly.  Four conductors dedicated to the handset, and two for a hookswitch.  Except:  If I'm not mistaken, Kellogg handsets are 3-conductor only, so you might have to fiddle with the wiring to get acceptable results. 

   

LarryInMichigan

I have a Kellogg 700A with a PC board network in it.  I took the network from a 1979 SC 500, which I bought for cheap at a flea market, and manged to just fit it into the phone shell.  I had to break off a few of the terminals on the board.  An AE mini network might also fit.

Larry

DARK FATHER

I went ahead and bought a mini network that will arrive at the same time as the phone.  I will need a schematic to hook it up properly.

Wallphone

You can find the schematics for the GTE mini-networks in the TCI Library. More excellent info can be found in the latest edition of Old-Time Telephones on pages 184 & 206.
Doug Pav

LarryInMichigan

I don't remember if I tried an AE mini network in my 700A or not, but the amount of space inside the shell is very limited.

Larry

AE_Collector

#6
No pictures, link to the ebaY auction or at minimum the ebaY number :(

I don't know what a Kellogg 700A is.

Terry


AE_Collector


DARK FATHER

That Ebay link is the VERY phone that I bought too!  I would have put pictures of it, but I had not yet contacted the owner to ask if I could post his.  Some people are VERY sensitive about that!

DARK FATHER

***UPDATE***
OK, it appears my Kellogg 700 has a DC receiver since it will not magnetize to my screwdriver.  Can someone give me a step-by-step (with a picture) how to wire it up?  It has three wires and no subset.  The mini-network has not arrived yet, but should in a day or so.

GG



I can't post a diagram but I can offer some pointers.

Kellogg receivers are kinda' odd and you may have an AC receiver there even though it doesn't attract a screwdriver.

The way to find out is to get a 500 set, and use any expedient method (alligator clips) to connect the Kellogg receiver in place of the normal receiver.  If it has no audio or very low volume, it's a DC receiver.  If the volume is similar to that of the native U1 or U3 receiver, it's an AC receiver and should *NOT* be wired like a DC receiver, or the audio will gradually get lower and lower until it's not usable. 

IF it's a DC receiver, one way to wire it is just in series with the transmitter.  That will get you a high sidetone level but it is correct for some phones (I don't know about the Kellogg 700 specifically). 

DARK FATHER

My mini network still has not arrived, but today I wired up the phone (three wires) and got a strong dial tone.  I can hear a incoming caller but he cannot hear me.  Any ideas?

GG



Yeah: you probably wired the transmitter and receiver in parallel, and the DC resistance of the receiver is low enough that there isn't enough current left over to provide adequate output from the transmitter.

Try wiring them in series.  If you have a three-wire connection (this would be typical for a WE F1) in which black is transmitter, red is common to transmitter and receiver, and white is receiver: connect black and white to the phone line, leave red alone for now, and see what happens. 

However I'd really suggest waiting until your mini network arrives and then wiring the whole thing correctly, "just in case" that receiver is really an AC receiver with a magnet hidden sufficiently inside that you can't detect it with the screwdriver test from the outside. 

DARK FATHER

OK, here is what I have.  I need to know which wire(s) from the mini network goes where in the phone.  I also need to know which phone line wires (not pictured) go where in the phone.  For the purpose of this picture the top screws are to be left to right # 1 and # 2.  The bottom three are left to right  # 3 # 4 and # 5.  This should simplify the answer that someone will give me.  HELP!!!