Classic Rotary Phones Forum

Telephone Identification, Repair & Restoration => Telephone Troubleshooting and Repair => Topic started by: j.bridwell on March 23, 2009, 09:45:31 PM

Title: Unable to locate a 684AT subset diagram
Post by: j.bridwell on March 23, 2009, 09:45:31 PM
I have a Western Electric subset labeled 684AT.  Nowhere can I find a wiring diagram.  The connections are labeled GND, BK, K, and E.  The previous owner connected four-conductor wiring, but has only two from the subset to the receiver.  I thought it would use at least three.  The phone does ring and works for incoming calls, but I'd like to see a diagram if one is available.  Any help is appreciated.  I can supply pictures if that would be helpful.
Title: Re: Unable to locate a 684AT subset diagram
Post by: Steve K on March 23, 2009, 09:50:59 PM
Hi:

Try this link, it should be close to what you have.

http://www.telephonecollectors.org/library/weco/634684a.pdf

Steve
Title: Re: Unable to locate a 684AT subset diagram
Post by: j.bridwell on March 23, 2009, 10:09:51 PM
Quote from: Steve K on March 23, 2009, 09:50:59 PM
Hi:

Try this link, it should be close to what you have.

http://www.telephonecollectors.org/library/weco/634684a.pdf

Steve

Thanks.  I've seen this one before.  Forgive my ignorance, but I'm new to these telephones.  I'm just not seeing L1 or L2 in my set so I don't know where to connect the incoming leads.  Not even sure if I'm following the tip party, ring party, or individual station.
Title: Re: Unable to locate a 684AT subset diagram
Post by: bingster on March 23, 2009, 10:30:28 PM
The terminals that are marked GND, BK, K, and E are all on a terminal board.  The L1, L2Y, etc. terminals are on the induction coil.  You may have a induction coil in your subset that is small with the terminals arranged around the coil in a "U" shape, or you may have an older induction coil that has wooden blocks on the end with the terminals on top of the blocks. 

I'm not sure what the "AT" designation is for.  Does yours have a glass vacuum tube in it by any chance?  If it does, disconnect all wiring for the tube and tape the connectors so they don't make contact with anything. 

All telephone service nowadays is "individual station."  What type of telephone are you connecting to the subset?  Whatever model you have, it should connect with a cord which contains either three or four conductors--never just two.
Title: Re: Unable to locate a 684AT subset diagram
Post by: Steve K on March 23, 2009, 10:35:17 PM
Tip (L1) goes to the R on the coil and the Ring (L2) goes to the Y terminal.  This is on the 101 (U) shaped coil.  As Bingster said it is individual station, unless of course you are still on a party line.  Do they still have those?

Steve
Title: Re: Unable to locate a 684AT subset diagram
Post by: Steve K on March 23, 2009, 10:37:21 PM
Scratch that, L1 is not the R terminal.  It might be identified as RR.
Title: Re: Unable to locate a 684AT subset diagram
Post by: j.bridwell on March 23, 2009, 10:44:52 PM
Maybe these will help...
Title: Re: Unable to locate a 684AT subset diagram
Post by: bingster on March 23, 2009, 10:52:22 PM
Ohhhhhhh... you're missing the induction coil that delivers the proper voltages to the telephones receiver and transmitter.  It should look like this:


Title: Re: Unable to locate a 684AT subset diagram
Post by: j.bridwell on March 23, 2009, 11:00:06 PM
Well, that explains a lot!  I think I've seen an induction coil for sale at one of the vintage phone stores.  Thanks so much.  A picture does help I guess.
Title: Re: Unable to locate a 684AT subset diagram
Post by: bingster on March 23, 2009, 11:06:28 PM
The photos definitely help.  And once you get the coil, you're good to go. :)
Title: Re: Unable to locate a 684AT subset diagram
Post by: j.bridwell on March 23, 2009, 11:13:46 PM
Blingster, thanks again.  That's a WE 104A induction coil (not a 101A coil)?
Title: Re: Unable to locate a 684AT subset diagram
Post by: bingster on March 23, 2009, 11:40:09 PM
You'll want the 101A for yours.  It's the standard individual station version. 
Title: Re: Unable to locate a 684AT subset diagram
Post by: j.bridwell on April 02, 2009, 05:08:34 PM
I got the 101A induction coil, but had to replace some of the existing wiring not to mention it was incorrect to begin with not having the coil.  Before I solder the connections, could you verify the leads are correct?  Maybe I have them inverted?  According to my diagram:

Red goes to C
Black to BK
Yellow to L2
White to K

Thanks!
Philip
Title: Re: Unable to locate a 684AT subset diagram
Post by: bingster on April 02, 2009, 06:41:30 PM
Comparing your photo and connection list to my 684A, it looks like it's exactly right on both counts. 
Title: Re: Unable to locate a 684AT subset diagram
Post by: j.bridwell on April 03, 2009, 10:33:24 AM
Almost there...

The ringer now works with the new coil and wiring.  Thanks so much for your help.  I'm curious about a couple last things and I'll let this thread die. :)  Is there a specification document, guide, or thread that outlines how to adjust the ringer?  For example, when the gong rests against a bell, how much space (maybe measured with a spark plug gauge) should be between the contacts?  Should the contacts ever actually touch or should there always be a given amount of space between them?  I assume the tension on the spring is just enough to prevent a tapping ringer?

And what's with the "E" terminal that isn't used?

This is my first foray into vintage telephones as my hobby has been model building for the past 40 years.  I've read a lot already and browsed threads until my head spun.  I want to read a lot more soon and hope these questions weren't too elementary for you!

Thanks,
Philip
Title: Re: Unable to locate a 684AT subset diagram
Post by: Dennis Markham on April 03, 2009, 10:50:59 AM
Philip, with regard to the clapper resting against the gong......I would rotate the gong, if you can so that the clapper/striker does not make contact with either gong while at rest.  It will stifle the ring at the end of the ringing cycle.  I don't think there is a specific measurement as far as distance.  I think the ringers ring differently depending on where it is connected.  So you can fine tune it to the ringing voltage where it will be working.  Adjust it away from the clapper and test it.  I like to hold one gong while it is ringing so that I am isolating the other side and just listen to what sounds best.  If it's ringing true and clear the it's good.  Then do the other one.  Sometimes if they're not spread far enough apart the clapper doesn't get a full swing and won't return as nicely.  Just doing this from experience it seems like the clapper pushes off the gong and if it's too far away it loses some strength for the return.  But just play with your gong until it sounds right....just don't tell anyone you spent time playing with your gong and clapper.  :)

I don't know about the E terminal but I would imagine that it's there for some other application.
Title: Re: Unable to locate a 684AT subset diagram
Post by: bingster on April 03, 2009, 04:06:35 PM
Not surprisingly for Western Electric, there actually is a measurement  for the space between the clapper ball and gongs when at rest.  It's 1/64" for the older ringer types.  But I do just as Dennis said--hook it up, call the number, let it ring away while you rotate each gong to find it's sweet spot. After doing that adjustment, you can adjust the bias spring to eliminate any "bell tap" caused by dialing, or by other phones on the same line being picked up. With that bias spring adjustment, you'll find there's an incredibly tiny sweet spot between the spot where you get bell tap and the spot where you get diminished ringer function.
Title: Re: Unable to locate a 684AT subset diagram
Post by: Dennis Markham on April 03, 2009, 04:32:03 PM
Thanks Bingster.....we all learn something every day.  I didn't know there was an actual measurement but I should have known.  The Bell System didn't leave anything to chance.