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1953 Stromberg Carlson 1243WK weird issues

Started by QUIKRIDE86, June 12, 2017, 11:31:28 PM

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QUIKRIDE86

Hi all, I have a 1953 Stromberg Carlson 1243WK phone I am trying to restore as a surprise for my wife. I'm hoping some members might be able to point me in the right direction in troubleshooting a wiring issue in updating it. I purchased a 4 wire modular cable to replace the original 4 prong plug. I wired the phone according to the attached diagram as it is the only one I found which matched what parts this phone has. I do not know if someone previously modified this or if it was this way from the factory but the dial has 5 wires instead of the usual 4 I found on almost all diagrams I found for this model phone online. In taking it apart to clean and paint I took pics and looked up the model numbers of the parts. It appears to have a regular 200595B network but has a Western Electric P-339952 dial (5 wires instead of the usual 4) and Sig Eng VP2-1 (single bell) ringer instead of the usual two bell ringer. When I plug it in to a standard land line I get a good dial tone and and able to dial out fine, speak, hear and hang up at the end of the call. On the other hand if I call in to it the bell does not ring (the plunger is free moving), if I pick up while in the call I can speak and hear fine but if I hang up the Stromberg it does not disconnect. I can pick up again and the other phone is still on the line. Only when the other phone hangs up does it disconnect. Has anyone run into this issue? I'm wondering if the network is bad. I have looked all over but haven't found anything about testing the network or other components. Any help would be greatly appreciated.  Steve

dsk

Hi, and welcome to the forum. Looks like the ringer circuit is the issue.  The ringer is an army type, and it may need more pwer than an ordinary ringer, so it may depend of the ringing current source.  The Straps L2-G and C1-C2 is important. I can only see one wire from the ringer, but the other may just be outside the picture. 
I guess you should concentrate around the ringer as the first thing.  I do not believe the capacitors are bad, but it may be the next to check out.

dsk

QUIKRIDE86

Interesting, do you know what voltage that type of ringer would run at? I could find no specs on it anywhere. I could disconnect it and try testing it with a power supply to see if it rings on it's own.  Steve

TelePlay

Are you using a standard POTS landline or do you have a VOIP line?

unbeldi

That "ringer" appears to me as a buzzer as often used in key systems. It is a part used by the Army Signal Corp. Perhaps it was installed to operate from a special signaling circuit with a DC power supply.  Is it even connected across the line ?

It should not be too hard to find the proper straight-line ringer for these sets.

Alex G. Bell

#5
Quote from: unbeldi on June 13, 2017, 09:44:43 AM
That "ringer" appears to me as a buzzer as often used in key systems. It is a part used by the Army Signal Corp. Perhaps it was installed to operate from a special signaling circuit with a DC power supply.  Is it even connected across the line ?

It should not be too hard to find the proper straight-line ringer for these sets.
I believe it is the ringer used in Signal Corps EE8 field telephones.  The top is a gong with a notch in the edge.  Flaps produced by slotting the edge are bent inward to provide a notch with flat side surfaces which the clapper strikes.  Impedance may be lower than a usual ringer to operate on lower voltage from a magneto but probably not very low since some EE8 circuits had multiple phones connected.

S-C 1243s are most commonly equipped with AE Type 24 dials which have a 3-contact normally open contact spring set for shorting the receiver and transmitter when the dial is off normal.  This method typically only requires 4 dial leads.  A WECo dial puts a normally closed contact in series with the receiver thus requires a 5th lead to the dial.

The statements about not releasing the line are unclear to me but if the ringer has a cap in series and the cap is not shorted or leaky this ringer should not be any problem.

unbeldi

It hard to judge the size of this VP2, but it seems only about an inch across.   The manuals (ca. 1950) I have of the EE-8 types specify an MC-131 for the ringer, which is a single gong used as cover over the two-coil motor and looks quite different.

Alex G. Bell

#7
Quote from: unbeldi on June 13, 2017, 10:18:55 AM
It hard to judge the size of this VP2, but it seems only about an inch across.   The manuals (ca. 1950) I have of the EE-8 types specify an MC-131 for the ringer, which is a single gong used as cover over the two-coil motor and looks quite different.
If the screws mounting the network visable above are #6 the shanks are about 1/8" dia. and heads are about 1/4-5/16" diameter and so are the ones holding the gong (if that's what it is) in place.  From that it seems to me to be a lot larger than 1" dia., like 2 or 3".  The MC-131 was about 3".

One could also pull a 1243 and look at the hole pattern for the grommetted base plate holes, which I think are for the ringer.

poplar1

Yes, it is a ringer. Probably army surplus and installed by a refurbisher. I've seen these in other 1243s.

is there a strap connecting L2 to G?

Is the ringer connected to 3 and C1? (It should also work if connected to L1 and C1.)

BTW, the dial is a Western Electric 6A.
"C'est pas une restauration, c'est une rénovation."--François Martin.

dsk

Quote from: QUIKRIDE86 on June 13, 2017, 09:06:43 AM
Interesting, do you know what voltage that type of ringer would run at? I could find no specs on it anywhere. I could disconnect it and try testing it with a power supply to see if it rings on it's own.  Steve
The ringer is the type used in US army field telephone EE-8, mine has a DC resistance of about 1200 ohms. The spec says 50 V at 20Hz.
I tried to measure mine together with a 1uf cap, and got something like 1.6 REN load.

That load may be tough for an ATA, but a POTS line should not make any problems.

If you remove the gong you could see if the armature is moving freely, and it should buzz instead of ringing.

dsk

QUIKRIDE86

Quote from: TelePlay on June 13, 2017, 09:39:41 AM
Are you using a standard POTS landline or do you have a VOIP line?

Standard POTS line to test (old analog line at my job). At home I do not have a landline so I am planning to use this gateway (http://www.myxlink.com/xlink_bt.aspx) to connect through my cell phone.

QUIKRIDE86

Quote from: Alex G. Bell on June 13, 2017, 10:25:31 AM
If the screws mounting the network visable above are #6 the shanks are about 1/8" dia. and heads are about 1/4-5/16" diameter and so are the ones holding the gong (if that's what it is) in place.  From that it seems to me to be a lot larger than 1" dia., like 2 or 3".  The MC-131 was about 3".

One could also pull a 1243 and look at the hole pattern for the grommetted base plate holes, which I think are for the ringer.

Correct, it is about 2" across.

QUIKRIDE86

Quote from: dsk on June 13, 2017, 12:08:35 PM
The ringer is the type used in US army field telephone EE-8, mine has a DC resistance of about 1200 ohms. The spec says 50 V at 20Hz.
I tried to measure mine together with a 1uf cap, and got something like 1.6 REN load.

That load may be tough for an ATA, but a POTS line should not make any problems.

If you remove the gong you could see if the armature is moving freely, and it should buzz instead of ringing.

dsk

I had it apart to clean and the armature is moving freely.

QUIKRIDE86

Quote from: unbeldi on June 13, 2017, 09:44:43 AM
That "ringer" appears to me as a buzzer as often used in key systems. It is a part used by the Army Signal Corp. Perhaps it was installed to operate from a special signaling circuit with a DC power supply.  Is it even connected across the line ?

It should not be too hard to find the proper straight-line ringer for these sets.

I checked and it is wired red to #3 and black to C-2.

Alex G. Bell

Quote from: QUIKRIDE86 on June 13, 2017, 02:58:02 PM
I had it apart to clean and the armature is moving freely.
I suggest posting a photo of the underside.  I'd expect that like the MC-131 it has two side-by-side coils and a permanent magnet around the back (as best as I remember the construction from years ago), no interrupter contacts in series with the windings.