WECO 2500D (3/73) DTMF Problem

[poorfellow]

Hello,

First post.  I'm glad to be here.

I have a formerly-excellent 2500D set that I use with AT&T POTS when I need to respond to DTMF prompts for conference calls, etc.  Prior to just now, the device worked flawlessly when generating DTMF from the keypad.  Now, when I press, I get a squeal.  Once the key bottoms-out, it goes back to silent, with reduced volume dialtone coming through.

Any quick fixes for this?  Any known causation, in case this is a common issue?

I've reversed the polarity in case something changed upstream from my home, but it hasn't.  The polarity is correct.

I appreciate any help or knowledge.

Thanks!

[HarrySmith]

First of all, Welcome to the forum! It sounds like you may have a dirty or faulty dial pad. What year is the phone? Can you add pictures? Some photos of the back of the dial & the wiring should help diagnose your issue.

[poorfellow]

Hey Harry,

Thanks for replying.

It's actually straight out of the box (NOS), a couple of weeks ago.  I went over the pad when I did just to make sure the contact were clean, free of carbon, and the pad was clear of debris.  It's exceptionally clean, and was working until today.  There seems to be some electrical issue.  I'll get some pictures up shortly, since that'll probably tell a better story than I can.

I do have some working 500s to keep me going as far as making and receiving calls until we can get this 2500 breathing again, and will get them all photographed for the collection forum as well.

It's great to be here!

-Lance

[poorfellow]

Alrighty, I was able to get some decent light for photos.

She's very clean.

[poorfellow]

Additional photos.

[HarrySmith]

Good looking phone. Those early pads are known to fail but that one looks fine. I was going to suggest cleaning the contacts but it sounds like you already did that. The only thing I can see is it looks like one of you wiring lugs is touching another terminal. That could be a problem. See picture, problem circled in red.

[Key2871]

Those dials can be troublesome. Unless you have the right tools to clean contacts, don't even try. The reason is  because you can foul contact adjustment with out really knowing it. And trying to get it back? Do you have hair to loose? Because it will frustrate you to no end of you don't have the proper tools to readjust those contacts.
I'm not feeding you a line, I have been there before, it's no easy task to do.
I say replace the dial, and be done with it.. I've seen several over the years, and only one was I able to get one working, and that was not easy to get adjusted. It was a dirty contact on the very back of the dial, but getting that contact back into adjustment was A pain in the butt. I told myself I would not do that anymore. I just replace the dial. I may have the newer equvalant the H dial, it will look the same out side, but it has a hard click type button. Or I do have the ITT electronic version. PM if interested.

[Stan S]

The ferrite on one of the pot cores is broken.
You can see the bobbin with the coil in the next to the last picture.
That pot core is toast.

[poorfellow]

Thanks to all for the replies.

The weirdest thing happened while I had it apart.  I plugged it in, and tested a few key combinations and it worked.  It still works after reassembly, which is an indicator to me that something is wonky - these shouldn't just stop and start working, but should be predictable.  This phone is also great at finding reversed polarity on jacks in the house, apparently.

Do the replacement keypads include the cores?  I'd like to keep everything as original as possible, rather than going to the IC generator for DTMF, but a predictably working phone is the final goal.  Also, is there an adjustment on these networks to increase inductance or something to raise the volume of the voice band without boosting the loop current?

If only my work used conference bridges that supported rotary callers.  I'm sure everyone remembers the days when 500-series (and even 300s) were still heavily installed in the system, and DTMF response systems would often have a "Rotary Callers, Please Hold" type message.

[poorfellow]

The ferrite on one of the pot cores is broken.
You can see the bobbin with the coil in the next to the last picture.
That pot core is toast.

It looks like the cover slipped while I was holding it, but I didn't notice that.  It seems to stay in place on its own.  Strange.

Does the fact that it's working now rule that core out, or is it likely causing intermittent function?

[HarrySmith]

I actually super glued a core on one once. It worked just fine. If you are going to replace the dial pad I would recommend using the next generation which eliminated the ferrite cores.

[Key2871]

If the ferrite coil is broken then that will cause problems.
You can try gluing it, but it could stop working again.
I've had one come to me years ago and I needed to replace the dial.

[poorfellow]

I'd like to hold onto this dial, since it has the matching date and the spelled-out "Operator" on the zero key.

But I may end-up taking you up on your offer to have a spare, Key2871.  It's my only TT phone, and I use it a lot for work calls.  No phone sounds as clear as the old WECOs when in a serviceable condition, and they just look great doing it.

[Key2871]

I understand completely. If I have a dial with that date, I'll let you know. How's that,

good luck, Ken.

[jsowers]

I'd like to hold onto this dial, since it has the matching date and the spelled-out "Operator" on the zero key.

But I may end-up taking you up on your offer to have a spare, Key2871.  It's my only TT phone, and I use it a lot for work calls.  No phone sounds as clear as the old WECOs when in a serviceable condition, and they just look great doing it.

There's also the option of having the touchpad repaired by a professional. You could easily ruin your touchpad. Steve Hilsz can repair and send you back the same touchpad for an affordable amount. Others on this Forum have used his services and I've seen only compliments about his work. He's very good at what he does. His webpage is http://www.navysalvage.com/ and his email address is on that page. Email him for the cost and tell him what you have before you work on your own touchpad. I think the older touchpads are much nicer to use than the ones with limited travel buttons and they can be very dependable if kept out of a dusty environment and not dropped on the floor.

I would also feel guilty if I didn't tell you something from a collector's point of view. Your phone is or was NOS in the box and taking it out of the box and using the phone makes it no longer NOS and thus reduces its collector value. We're not talking hundreds of dollars here. Just that phones new in the box command premium prices in auctions, so just be aware that using something NOS takes some of the value away. Like driving a new car off the lot. It's only new once.

It's your business what you do with your phone, so I'm not trying to tell you to put it back in the box. I hope I'm not coming across as being critical. There are as many opinions on this as there are collectors, so I'm sure others will chime in with theirs and this is just mine and worth one or two cents. I just wanted you to be aware of what others think about NOS phones. Try to keep the phone as original as you can, and I can sense that's what you want to do.

There are plenty of used WE phones around that will work reliably for years and years, but not many that are NOS. I agree with your opinion of WE phones and those are what I use in my house too. Some have been connected for 30 years with no problems, even after a lightning strike that killed an AT&T electronic phone and a laptop modem. WE phones were built to last for generations.

And welcome to the Forum! Show us your collection when you get a chance. We love pictures.