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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

Quote from: Alex G. Bell on June 13, 2017, 03:03:17 PM
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.
I can take a pic when I get home but what I saw when it was apart was a single coil (centered under the gong)with a freely moving pole piece that extended out both sides and was able to contact the gong either direction.....also there was no spring attached to it.

dsk

Do you have a meter?  If yes, could you measure the resistance between black and red? You do not have to remove the wires.
dsk

Alex G. Bell

#17
Quote from: QUIKRIDE86 on June 13, 2017, 03:10:01 PM
I can take a pic when I get home but what I saw when it was apart was a single coil (centered under the gong)with a freely moving pole piece that extended out both sides and was able to contact the gong either direction.....also there was no spring attached to it.
OK.  I've seen bells or ringers with that kind of construction.  More important is whether it contains a permanent magnet and/or any contacts, and somewhat secondarily, the resistance.  If it contains contacts certainly or does not contain a permanent magnet perhaps it's not a "magneto ringer" and not intended for operation from low frequency high voltage AC.

However no issue with the ringer would be logically related to this:

1) "When I plug it in to a standard land line I get a good dial tone and am able to dial out fine, speak, hear and hang up at the end of the call. "

2) "On the other hand if I call in to it the bell does not ring (the plunger is free moving),"

3) "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."

(1) and (3) are at first glance contradictory to each other, depending on exactly what you mean by "other".  Either it releases the line or it does not.  If another phone is off hook on the same called line of course the line will not be released until both hang up.  However release of the connection is  normally mostly controlled by the calling end, with timeout from the called end, so unless the called phone hangs up for 20-35 seconds the incoming call will still be there when the called phone goes off hook again if the caller did not hang up in the mean time. 

So you need to clarify what you mean by this.  One interpretation is that this is perfectly normal and any phone would do this.

poplar1

Note the heavy black lines between L2--G and C1--C2 in the diagram. Did you install those two straps (short wires)?
"C'est pas une restauration, c'est une rénovation."--François Martin.

QUIKRIDE86

Quote from: Alex G. Bell on June 13, 2017, 03:57:26 PM
OK.  I've seen bells or ringers with that kind of construction.  More important is whether it contains a permanent magnet and/or any contacts, and somewhat secondarily, the resistance.  If it contains contacts certainly or does not contain a permanent magnet perhaps it's not a "magneto ringer" and not intended for operation from low frequency high voltage AC.

However no issue with the ringer would be logically related to this:

1) "When I plug it in to a standard land line I get a good dial tone and am able to dial out fine, speak, hear and hang up at the end of the call. "

2) "On the other hand if I call in to it the bell does not ring (the plunger is free moving),"

3) "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."

(1) and (3) are at first glance contradictory to each other, depending on exactly what you mean by "other".  Either it releases the line or it does not.  If another phone is off hook on the same called line of course the line will not be released until both hang up.  However release of the connection is  normally mostly controlled by the calling end, with timeout from the called end, so unless the called phone hangs up for 20-35 seconds the incoming call will still be there when the called phone goes off hook again if the caller did not hang up in the mean time. 

So you need to clarify what you mean by this.  One interpretation is that this is perfectly normal and any phone would do this.
The ringer doesn't have contacts under the bell or gong. I will check the resistance when I get home and snap a couple pics. When I moved it with no power I did feel some 'pull' like there was a magnet involved. I will check to see if the pole is magnetized also. As for the statements i made I meant that it seemed that on calling FROM the phone to another (my cell) I was able to hang up disconnecting the call but when I called the Stromberg from my cell phone and hung up the Stromberg it did not disconnect the call. From what you said about it taking 20-30 sec for the disconnect this makes more sense to me (and apparently is not a problem with the phone). I'll try to check those other things about the bell soon (about an hr or two) when I leave work. Steve

QUIKRIDE86

Quote from: poplar1 on June 13, 2017, 04:35:40 PM
Note the heavy black lines between L2--G and C1--C2 in the diagram. Did you install those two straps (short wires)?
I don't remember it having a strap from L2 to G but I'll check that when I return. It definately has a strap from C1 to C2 though.  Steve

Alex G. Bell

Quote from: QUIKRIDE86 on June 13, 2017, 04:40:07 PM
The ringer doesn't have contacts under the bell or gong. I will check the resistance when I get home and snap a couple pics. When I moved it with no power I did feel some 'pull' like there was a magnet involved. I will check to see if the pole is magnetized also. As for the statements i made I meant that it seemed that on calling FROM the phone to another (my cell) I was able to hang up disconnecting the call but when I called the Stromberg from my cell phone and hung up the Stromberg it did not disconnect the call. From what you said about it taking 20-30 sec for the disconnect this makes more sense to me (and apparently is not a problem with the phone). I'll try to check those other things about the bell soon (about an hr or two) when I leave work. Steve
Since apparently you have a DMM or VOM, the best way to satisfy yourself that the S-C is releasing the line when it should is to put the DMM/VOM on a range > 50VDC properly poled so the meter goes up scale.  When the phone is on hook you will see ~48-50VDC on a telco analog line.  When the phone is off hook you will see typically 6-12V, even as low as 2V on a long line with a low resistance speech circuit.  The voltage will return to ~48-50V immediately when the cradle switch is operated. 

You can also test for ringer capacitor leakage by putting the meter in series with the phone still set to VDC.  If the capacitor is good (not leaky) the meter will eventually settle near 0V once the capacitor charges.  If the voltage is not 0 or close to it the capacitor is leaky or there is some other leakage fault.

This is a much more valid test than measuring resistance since leakage tends to be much greater with greater applied voltage and VOMs and DMMs typically apply 1½-3V to avoid damage to semiconductors.

poplar1

Quote from: QUIKRIDE86 on June 13, 2017, 04:45:14 PM
I don't remember it having a strap from L2 to G but I'll check that when I return. It definately has a strap from C1 to C2 though.  Steve

If the phone originally had a 3-conductor hardwired cord connected to L1, L2 and G -- but no strap from L2 to G --then to make the ringer function, it would have been necessary to connect the wires from L2 and G together at the wall connecting block.

When converting a phone from hardwired to modular, it is necessary to bridge the ringer circuit and talk circuit inside the phone.
"C'est pas une restauration, c'est une rénovation."--François Martin.

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.
Just an FYI it measures 2-1/4" approx. It does look as if the ringer was replaced by someone. On closer inspection as I unscrewed it from the base I could see it appears someone enlarged the holes with a dull pair of scissors. LOL. I cleaned up the holes with a countersink before replacing the ringer assembly.

QUIKRIDE86

Quote from: Alex G. Bell on June 13, 2017, 03:03:17 PM
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.
I checked and it definitely is one coil on this one. No contacts.There is a magnet in the cad plated side to the right in the photo. The 'striker' is not magnetized and appears to be the same both ends.

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 checked the resistance on this one and it came out at 2.7k ohms. Don't know if that's good or bad.

QUIKRIDE86

Quote from: poplar1 on June 13, 2017, 05:02:16 PM
If the phone originally had a 3-conductor hardwired cord connected to L1, L2 and G -- but no strap from L2 to G --then to make the ringer function, it would have been necessary to connect the wires from L2 and G together at the wall connecting block.

When converting a phone from hardwired to modular, it is necessary to bridge the ringer circuit and talk circuit inside the phone.
Yup, looks like the wires were connected at the block! I added a jumper across G and C-1 (which also jumps to C-2). Would this be correct?

Alex G. Bell

2.7K is quite reasonable.  Without a bias spring it may tap when other phone seize and release the line or rotary dial but it appears to be a "magneto" ringer.  So next focus on whether it seizes and releases the line properly based on DC voltage measurement and if that's okay why it does not ring is the only real problem.

QUIKRIDE86

Quote from: QUIKRIDE86 on June 13, 2017, 07:56:05 PM
Yup, looks like the wires were connected at the block! I added a jumper across G and C-1 (which also jumps to C-2). Would this be correct?
Opps.....just realized I connected the wrong ones poplar1. I removed the jumper I put between G and C-1 and moved it to between L2 and G. Steve

QUIKRIDE86

Sorry for the multiple posts everyone. Just wanted to address everyone's comments once I got back home from work. With these changes I will bring the phone to my job tomorrow to try it out. If it doesn't ring I'll try and get the voltages to further troubleshoot. Steve