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WE 1500 Keypad Problem

Started by LarryInMichigan, November 03, 2011, 12:42:31 PM

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LarryInMichigan

I bought a WE 1500D, dated 2-67, today, and when I tried using it, I found that the buttons 1-6 do not work properly (7-0 work).  It sounds like they only produce a single frequency tone.  I looked carefully at the TT pad and the wiring, and I cannot see anything apparently wrong.  Does anyone have any suggestions about what might be wrong or what to try?

Thank You


Larry

Dave F

Hi Larry,

While it is possible that you have a defective oscillator coil, that problem is almost always due to dirty dial contacts.  If you carefully clean all the contacts which close when the various buttons are pushed, there is a good chance that your problem will go away.  These contacts are very fragile and need to be handled gently.  Often, you only need to slide a piece of paper between them as you push the appropriate buttons to dislodge any accumulated dirt.  Don't use any kind of harsh abrasive, such as emery paper, as that would ruin the plating and only make the problem worse in the long run.

Dave

Phonesrfun

Don't use contact cleaner spray either, unless you have the patience to let it sit for a day or two to dry out.  This is according to my experience.

The one-tone symptom is indicative of contact issues, most commonly,  There are row and column switches on each of the four edges of the dial.  Your problem sounds like the two row switches for 1-2-3, and 4-5-6 may not be making contact.

There are also switches on the back of the dial mounted right on the circuit board.  Clean those as Dave has instructed too.
-Bill G

LarryInMichigan

Thank you.  I will give it a try.  I really bought the phone because it was $10 on sale, and I figured that I could resell it for more.  The phone is white and in pretty good condition. 

Larry

Dave F

Quote from: LarryInMichigan on November 03, 2011, 01:31:26 PM
Thank you.  I will give it a try.  I really bought the phone because it was $10 on sale, and I figured that I could resell it for more.  The phone is white and in pretty good condition. 

Larry
Great deal!  I'd buy any 1500 set that looked good for $10.  Heck, the faceplate alone is worth more than that.

GG



To isolate which tones aren't working, do this:

Press 1 + 2 at the same time, listen for tone
Press 4 + 5 at the same time, listen for slightly higher pitched tone
Press 7 + 8 at the same time, listen for slightly higher pitched tone.

Then press 1 + 4
then 2 + 5
then 3 + 6

If any of those combinations don't give you a consistent tone, you've found a row or a column with dirty switch contacts.

To pass a piece of paper between the contacts:
Gently pry off the transparent greenish front and rear cover.
Press the buttons while looking carefully to see which actuators are being operated in common.
Cut a narrow strip of plain white office paper, not glossy paper, that will fit into the relevant space.
Place the paper between a set of contacts, then press a button that operates those contacts, then pull the piece of paper out.  Repeat a couple of times for each set of contacts that may be giving you trouble.

And of course get back to us and let us know what happened.

LarryInMichigan

I did some testing, and the problem is not with the switch contacts.  There are actually two tones being generated when the 1-6 buttons are down, but one of the tones is faint and off-frequency.  It's a shame that the keypad does not work because the phone is in otherwise good shape, and absolutely all of the dates are from 2-67 or very close.  I plan to list the phone for sale.  If anyone is interested, make me an offer before I place it on ebay.

Larry

AE_Collector

For anyone who doesn't get how DTMF touchpads work, each digit is a combination of two different frequncies, thus the term DTMF (Dual Tone Multi Frequency). There are 7 different frequencies, each one corresponding to one row of buttons both verticle or horizontal. Thus it is not uncommon for all the buttons in a row in either dirrection to quit if something goes wrong with one individual frequency or the contacts associated with that frequency.

Terry

GG



Larry, try the paper trick with each of the contacts on the "common" switch at the back of the dial.  What you're describing sounds like it may be that the common switch isn't making good contact for one of the two coil circuits in the oscillator.  Especially if you notice that the tone varies slightly if you shift your finger around on the button or vary the pressure on the button.


Dave F

Larry,

It's a good idea to do what GG suggests.  Once you have absolutely determined that dirty contacts are not the problem, then the next most likely suspect is a broken wire from one of the coils.  These are the tiny thin wires that come from the coil interiors and solder to the pins that hold the coil to the circuit board.  Use a magnifying glass and check carefully.  You may find that one (or more) of these wires has been broken.  If it has, it may or may not be feasible to re-solder it to its pin.  Reconnecting such a broken wire is tricky and might not be possible because the wires are so tiny and fragile.  If that's the problem, and if it can't be fixed, then you need a new dial.  Those old 25A3 dials do turn up on eBay from time to time.  If you can get a replacement for about $20, you will have a phone worth ~$100.00.  Waiting for a replacement dial sounds like a better deal than dumping a non-working phone for maybe $25.  Keep us posted.

jsowers

Larry, you could also contact Steve Hilsz and see what he would charge for repairing the touchpad. His prices are very, very reasonable and his service is excellent from all reports.

Here's his website where you can get the contact info and a lot of tips...

http://www.navysalvage.com/
Jonathan

JorgeAmely

Larry:

Is the 1500 model the one without * and #?
Jorge

LarryInMichigan

I might give Steve Hilsz a try.  I have never heard of him doing TT keypads, but it wouldn't hurt to ask.

This pad has the ten buttons 1-0 without the '*' and '#', but there are actually holes covered with pieces of square gray tape in the keypad where the two extra keys would have gone.  The top of the keypad is stamped "25W3" and "2-67".

I haven't had a chance to look more at the switch contacts yet.

Larry

Dave F

Quote from: LarryInMichigan on November 05, 2011, 08:41:34 PM
This pad has the ten buttons 1-0 without the '*' and '#', but there are actually holes covered with pieces of square gray tape in the keypad where the two extra keys would have gone.  The top of the keypad is stamped "25W3" and "2-67".

Larry

Larry,

The 25W3 dial succeeded the 25A3 and was a transition  between 10 and 12 button dials.  Electrically, it was the same as the earlier 25A3.  Only the front was different.  You can read more about it here:

http://www.classicrotaryphones.com/forum/index.php?topic=3720.0

Dave

LarryInMichigan

Well, I took a good look at the common switch contacts and the wires on the coils could not find any problems, but buttons 1-6 still produce faint tones with the wrong frequencies.  I am about to give up and try to sell the phone for whatever I can get.

Larry