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How Can I Check A Ringer Coil?

Started by DiaLen, September 12, 2015, 08:50:42 AM

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DiaLen

I have a 1954 WE 500 desk phone that works well, except it won't ring. I've gone through the wiring a couple of times and am confident that it's correct. I have moved the black ringer wire to the L1 terminal.
I'm suspicious of the ringer coil. My very basic knowledge of coils says I should be able to measure continuity through two of the four ringer wires if the coil is good. However, I haven't been able to do so. I think the coil is bad.
Am I thinking correctly? Also, if I am, which two terminals on the coil should I check?
I did get continuity through all four wires measured between the coil terminals and the network terminals, so the old wires seem to be good.
I am using my multimeter for the tests.
Thanks for any help anyone can give me.
-Len
Be faithful to the commitments of your life.

Ktownphoneco

It should have a C4 ringer installed.   The two coils in the ringer are red and slate/red (approx 2862 ohms) and slate and black (approx 1067 ohms) measured on a C4A ringer.
Connections for bridged ringing :   Slate connects to terminal "K" on network
                                                       Slate/Red connects to terminal "A" on network
                                                       Red connects to "L2" on network
                                                       Black connects to terminal "L1" on network

Jeff Lamb


G-Man

You should have continuity between the following ringer wires, but be sure to disconnect them from the circuit before checking them.

       
  • RED and RED/SLATE
  • BLACK and SLATE

G-Man

Here is a diagram showing the proper connections for your ringer.

DiaLen

Well,
First, thank you for your quick responses.
I've measures the resistance in the coils and came real close to the values predicted:
red-slate/red measured 2794 ohms
slate-black measured 1023 ohms
So I guess that means the coils are good. I still have not been able to measure continuity through either coil though, and that puzzles me. Maybe I'm not supposed to.
I did recheck the connections at the network and they're correct.
I'll keep playing with it.
Thanks for your help.
-Len
Be faithful to the commitments of your life.

DiaLen

Update:
Problem solved!
Using my electrical knowledge and Windex.... well, using Windex, I was able to get the phone to ring.  :-[
The gong pivots on a brass plate, which rests up against a steel plate. Apparently, over the many years a sort of sticky crud had gotten between the two plates where I couldn't see it. It was just enough to hold the gong back from moving.
I've got it ringing now but it's kind of sluggish. I'll have to figure out a way of cleaning it without taking it apart. I've read that these ringers may stop working if they're taken apart.
Anyhow, mystery uncovered.
Thanks for the help.
-Len  :)
Be faithful to the commitments of your life.

Ktownphoneco

You could be correct, in that there may be something "sticky" that's made it's way into the clapper area of the ringer.    However, keep in mind that the ringer has a round magnet (flat at each end) located at the very bottom and to the left of the clapper, and the copper or brass colored clapper spring you described.      That in itself may give the impression that theirs something "sticky" in between the clapper and either of the 2 pieces of metal that act as clapper stops, because the magnet is applying a constant pull on the clapper.        It could be that the clapper bias spring may be applying too much pressure on the clapper, impeding it's movement somewhat.     Place it in the slot on the bias spring positioning bracket where there's the least amount of tension on the spring.   That should be the far left position when looking straight down at the positioning bracket and gongs, as shown in one of the pictures below.   
Also look around the round magnet and remove any metal particles that may have attracted to the magnet over the years.     If there is in fact, some "sticky" stuff interfering with the clapper movement, you can safely remove the clapper for easier cleaning, by removing the clapper mounting screw (shown in picture).         To re-assemble, you'll need to guide the clapper up through the square opening in the top of the ringer frame, and also guide the bias spring carefully through the groove and notch area of the bias spring positioning bracket.    But the process is pretty straight forward.

Reference pictures attached.

Jeff Lamb 

DiaLen

Great information and photos Jeff. Thank you.
I didn't realize the clapper assembly could be removed separately.
I'll get this done this evening.
I learned a few things today! Thanks again.
-Len
Be faithful to the commitments of your life.