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This Phone Wants to Ring but Won't

Started by rp2813, February 20, 2009, 03:10:02 PM

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rp2813

Hey guys, bear with me here as I provide the backstory on a '78 WE 2500MM with 2-wire ringer coil.  I don't know what the "MM" stands for but it looks like your basic single line phone inside and out.

When I got the phone I needed to reverse the polarity to get it to dial out, but the phone wouldn't ring on incoming calls.  The current configuration has red mounting cord lead terminating on L1 and the green on "A." 

I did a search here and found another thread where 2-wire vs. 4-wire ringer coils were being discussed, got a suggestion there to jump the L1 and K terminals (red ringer wire terms on K and black on L1) but that didn't help.  I've decided to create a new thread for this problem since the other one's title may not be inviting as much input from the membership.

I am pretty sure the ringer coil is drawing current.  I've determined this due to an issue I had with my bell chime ringer box not chiming anymore.  It was coincidental with adding a '53 500 that I deployed to ring in the basement.  When I unplugged the '53, the chime started chiming again.  Now with the 2500 plugged in, the chime isn't functioning.  I unplug the 2500 and the chime works.  So this tells me the 2500's ringer is drawing current.  The whole thing with not having enough current for the chime to work is a separate issue that I may need to take up with my service provider, but there is a definite corelation between adding an additional ringing phone and losing the chime function.  So it seems the 2500's ringer wants to work but for some reason it can't.  There is zero movement of the striker during the ring cycle.

Since there isn't much difference between 500's and 2500's other than the dial circuitry (right?) I'm hoping someone here can make some suggestions.  I have never encountered a 2-wire ringer coil before so this is all new to me.  I want to give this phone to a friend but it's gotta be able to ring.

TIA for any suggestions,

Ralph
Ralph

Dennis Markham

I know this sounds simple but did you adjust the bias tension spring on the ringer?  Sometimes I have seen those ringers barely move with the spring in one position and simply moving it to the more relaxed position will make all the difference.

rp2813

Thanks Dennis, I will try that and report back.
Ralph

rp2813

Dennis, I changed the position of the spring.  It is now in the "more relaxed" position but there is still no ringing action.  My next step will be to once again try the jumper wire and see if that provides results now that the spring has been repositioned.  Not sure what would be next if that doesn't work.  I'll try to take another look at things sometime over the next few days.

Ralph
Ralph

rp2813

The jumper wire didn't help.  I noticed that the spade on the end of the mounting cord's black lead had broken off so I fixed that connection thinking it could be related but it wasn't.  I still think this is a wiring problem unless the two-wire coils are known to have failure issues.  However, since I'm pretty sure the ringer is drawing current, the coil may be fine.  I don't have any similar network blocks to compare to but will try putting this phone and a 500 side by side and see if that provides any clues.  I hate to give up because things like this are usually very simple to fix, but diagnosing is so far hit and miss, and miss some more.

Ralph
Ralph

Dennis Markham

Where is Tip & Ring when we need him?

I looked at the only touch tone set I have and it's a 2500MG.  Your MM series MAY mean that it's M=Modular and M=Single line w/ A-lead control for 1A2. 4-conductor mounting cord and terminal strip installed below dial.  Originally used in applications where the ringer circuit had to be brought out through the mounting cord.

That info I got from Paul F's site.  I'm not sure what it means.  I'm not an electrical guy so I'm not sure what it means that the ringer circuit has to be brought out through the mounting cord.

I did look at the TCI Technical Library and there is a diagram for a 2500DM.  It is seen here:

http://telephonecollectors.org/library/weco/2500dm.pdf

But that diagram shows a 4 conductor ringer.  It shows the mounting cord Red to L2 and Green to L1 but since you reversed them that should be of no factor.

Your ringer leads are red and black?  Try connecting them Red to L2 and Black to L1 and jump A and K together.  Again, I'm not an electrical guy but that looks like it might complete the circuit------or blow up your phone! 

benhutcherson

I picked up a 2500MM over the weekend, and it has a sticker on the bottom which states that it is to be used on business lines only. I'm not sure what difference that makes, but I'd guess that it has some significance here.

I'm not sure what that means, as it appears to me inside and out to be a standard 2500 set with a 4228 network. I haven't had a chance yet to try it, but when I do, I'll report back.

Dennis Markham

That may explain the description on Paul's site, where it says the ringer circuit must be brought out through the mounting cord.

Steve K

Ralph:

Your phone may have been wired for a 1A2 KSU but you should be able to make it ring.  Do not connect the two ringer wires across the tip and ring (L1 and L2).  You do need the capacitor in the circuit.  The capacitor is between A and K on the network.  So, connect the black ringer wire to L2, the red ringer wire to K and jumper A to L1. The ringer should not be polarity sensitive.

Steve

rp2813

Thanks for all the suggestions.  I swear I saw a list of 2500 suffixes somewhere via a link from a post here, but don't recall seeing the "MM" information.  Steve, I will try your suggestion of jumping from A to K. 

Dennis, I'm an old hand at blowing up phones.  Or maybe you missed my story about the 202 I plugged into an electrical outlet because I wanted a phone in my room when I was about 7 years old.

Ralph
Ralph

HobieSport

[quoute] Dennis, I'm an old hand at blowing up phones.  Or maybe you missed my story about the 202 I plugged into an electrical outlet because I wanted a phone in my room when I was about 7 years old.

Ralph
[/quote]

I respected you at age 5 Ralph.  Good work.

Dennis Markham

Ralph, do like Steve K said and not what I said.  Like I mentioned, I am not a wizard when it comes to wiring sets other than the standard 500's.  I will be after I keep reading from others here.  Thanks to Steve.

rp2813

Well, I did what Steve suggested and still no ringer action.  I'm wondering if this phone simply isn't designed to ring on a POTS line.  The talk about the circuit being brought out through the mounting cord is throwing me.  What sort of situation is it when the mounting cord isn't involved with the ringer circuit?  I just assumed the ringer got its juice via the mounting cord leads.  What am I missing here?  I'd have to go along with Dennis in interpreting that info as meaning the ringer leads need to term on L1 and L2. 

Additionally, regarding blowing up the phone, since it's a 2500 I'm not too concerned if I wreck it.  Another one will come along that's made for POTS and that's probably what I should wait for.  All I'm trying to do is find a basic 2500 for a friend who wants one and can't get out much to find one on his own.  This 2500MM is driving me nuts and it's not even a nice collectible rotary taking up my time.  It may end up being a parts phone as I'm nearing the end of my rope with it, but I may take one more stab at it with the L1 & L2 connection.

Ralph
Ralph

Steve K

Ralph:

Make sure that you don't jump from A to K as you mentioned in a previous post, that would short out the capacitor.  Connecting the leads of the ringer to tip and ring probably will not work as you need some type of capacitor in series with the ringer coil. 

When these phones were connected to key systems the audible signaling voltage came through a separate pair of wires for the ring current.

Steve

rp2813

I think my attempts at jumping between terminals have become blurred because for some reason I'm not remembering trying the jumper between A and L1.  I'll try that again.  I also printed up the diagram for the 2500MM since it shows the arrangement with a 2-wire coil.  I'll check the connections against that diagram (with hopes that they aren't any different for POTS applications) and also try the A-to-L1 jumper and see what I get.  Stay tuned.

Ralph
Ralph