"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

First phone, first question

Started by JohnW63, February 20, 2019, 10:57:53 PM

Previous topic - Next topic


I picked up what looks to be a 1970s Stromberg Carson S-C500DQM phone off of eBay. It dials and makes calls. It does not ring. My memory of this type of phone says I should hear it clicking as the dial comes back to the home position and it doesn't, but I could be wrong.  I found a diagram of a phone on a German site, that looks close enough to be right. I changed the position of the ringer lines to match and still have no ring. I don't hear any buzzing to indicate pulses going through anything. I've moved the ringer volume lever both ways. I've read it COULD be a non ringer phone, but since all the wires and coil are there, that would seem un-likely. It has a large resistor like component, that says 400 VDC, and 620M but the diagram says it should be a capacitor. It looks like a white cylinder of soap to me!  The diagram also shows it between the silver wires, but this looks to be between the red and silver/stripe wire.

So... do I need to post an internal picture ? What else should I look for ?


Quote from: JohnW63 on February 20, 2019, 10:57:53 PM I need to post an internal picture ?

Welcome.  :)
Add external and internal photos, inc a photo of rear of dial.
A collector of  'Monochrome Phones with Sepia Tones'   ...and a Duck!
Vintage Phones - 10% man made, 90% Tribble


That diagrams suggests its got a frequency ringer, which may mean you are out of luck unless you can change it for a straight-line type.
We need photos to be able to confirm the ringer type please.


John   .... Welcome to the forum.   I'm not any sort of authority on Stromberg Carlson sets, but I suspect a SC 500"D" series set uses a straight line ringer.      Your set may have been set up for what's commonly called "ground ringing".    That system isn't used anymore.     Try this :   using the conductor color codes on the ringer itself, connect the "BLACK" conductor to terminal "L1" on the telephone's network.    Connect the "RED" conductor to terminal "L2" on the network.     Connect the "GRAY or SLATE" colored conductor to terminal "K" on the network, and finally, connect the "SLATE / RED" colored conductor to terminal "A" on the network.     Test the telephone and see if the ringer is functioning properly.

Jeff Lamb



Panasonic 308/616 Magicjack service


If your ringer has a capacator soldered on the coil, you have a tuned (partyline) ringer.A SL ringer uses the capacator hidden in the network between A & K terminals



When I first opened the phone the Red and Black ringer lines were in that position. The slate and slate with stripe were reverse of that, which I changed after looking at the diagram. So, I put them in the position you suggested and we still have no ring.  I'll post the pictures tonight of the guts. Oh, and when I first inspected it, the black wire from the phone line was off and wrapped with electrical tape. I removed that and connected it under the E connection, since that was the only unused spot and it made sense.








GM Note:  Images posted using external links have been downloaded and attached to this topic. Externally linked images are not allowed on the CRPF

The above 3 topics showing the damage externally linked images will do to topic over time can be found in the major photo board

and the worst example of damage done was with the ending of Picassa - moving all Picassa images to Google and thereby changing the URLs of the externally linked Picassa images making them disappear from the forum topics - is best example of why externally linked images are not allowed. New members don't know this so this is also a reminder to all members not to use external image links


That looks like a party line frequency ringer designed to ring at a specific frequency that is probably not the 20 Hz normally used on standard phone lines today.  You may find a marking or label on it that indicates ringing frequency.  The solution is probably to replace the ringer with a standard C4A or C4B 20 Hz ringer.  They are very commonly found.


I did a quick Google search for those ringers and I think it got confused. Anyone have a source I could check out ?

In the future, should I buy another older phone, is there a way I can avoid getting another " Doesn't work with modern phone specs " telephone ?


You really can't tell what ringer is in the set, unless the seller takes a good picture of the insides. I had an ITT 500 from my parents house, and when the CO was changed they wanted the phone's returned, and I found out why. Because the older system used party service even though the phone rang normal. And I connected up the old phone to the line and it would not ring, because it was a frequency ringer. So I swapped it out with a regular ringer.
If you want a ITT ringer that is 20 hz let me know via pm I have a couple in my box of stuff.



Is the whole section with the coil and arm the ringer ? Is it just screws removed to swap it or do I need to remove some rivets ?


Quote from: JohnW63 on February 22, 2019, 10:06:07 PM
Is the whole section with the coil and arm the ringer ? Is it just screws removed to swap it or do I need to remove some rivets ?
Just two screws to loosen from above, right next to the bells on either side, and it will pull out. They are captive screws, so just loosen them. Four wires to disconnect, as you know. The capacitor (large tubular off white piece) may or may not work with the straight line ringer, but leave it there and see what happens. It may not matter. It should ideally be 1 microfarad or so. It could be connected directly to the ringer, in which case you will need to connect it to the new ringer to the same wire.

When you get the new ringer, compare it to the old one and you'll see what to look for. Frequency ringers mostly have a tuning piece--that's the piece that sticks up on yours and has a brass cylinder with a setscrew. That piece helps tune the ringer to the frequency. Also the clapper between the bells doesn't move as easily as a straight line ringer and often the clapper is differently shaped.