ITT 500 Telephone Ringer Problem

[mblythe]

Hi, I recently picked up a nice green ITT 500 series telephone, which can place and receive calls just fine, but the ringer will not ring. It seemed to be wired for bridged ringing already, with no wires connected to ground. The ringer wires were originally like this:

red -> L1
black -> L2
striped -> A
gray -> K

I tried swapping the red and black wires, but it had no effect.

The phone is dated 12-73 on the bottom. I'm wondering if there is other rewiring required. For instance, I know that some Trimline telephones before 72 require some additional rewiring.

Any tips appreciated, including how to identify exactly which 500 model I have and what wiring diagram would be the best match. Some photos attached, and I'm glad to post more on request.

Thanks!

[poplar1]

Have you tried turning the ringer adjusting wheel in the direction shown by the arrow next to the word "LOUD"? The gongs appear to be touching the clapper (too close).

[mblythe]

Yes, I have tried the dial at both extremes and in the center. No change. The clapper doesn't move at all. I even tried move the little bias wire to no effect.

Here is a closer look at the bells / ringer

[poplar1]

It appears to be wired correctly, so you probably have either an open capacitor or an open ringer coil.

[mblythe]

Meaning that component would need to be replaced? Any way to determine which it is?

[poplar1]

The capacitor is inside the network, and is connected to the A and K terminals. If it is open, you can just connect another capacitor of about 0.5 uF (microfarads) to those two terminals (without opening the network).

The best way to test the ringer is with an ohm-meter.
With the ringer leads disconnected, there should be about 2650 ohms between the red and the slate/red leads, and about 1000 ohms between the slate and black leads.

Here is a diagram for a Stromberg-Carlson 500 that Jeff posted the other day. It is the same as your phone, except that the black ringer wire should be on L1 rather than G:

http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=16607.0;attach=146076

If the link doesn't work, here is the topic:
http://www.classicrotaryphones.com/forum/index.php?topic=16607.msg171791#msg171791

[Kenton K]

If nothing works, I will be more than happy to send you a ringer. PM me if your interested.

Ken

[mblythe]

Thanks for the help poplar1. It must be time to invest in an ohm-meter.

Kenton, thanks for the offer! I will let you know if it turns out to be the ringer.