2702 repair

[Argyris]

Hi all—

I have a 2702 (Princess) set, dated 1971, that was working fine until today. When I dial it now, I have two problems:

—when buttons are pressed, they sometimes fail to break dial tone. Sometimes it happens belatedly, after three or four tones.
—the tones themselves sound wrong to me, sort of squeaky and higher-pitched than normal. If the call does go through (it usually doesn't) I get the wrong number.

Any advice? Phone has been in place for a couple of years without problems. Last time I dialed out from it was about a week ago.

[Key2871]

Sounds like a new dial is required. I don't know if it can be repaired. Does  the dial guy fix those??

[Babybearjs]

just replace the dial, its easier that way.

[LarryInMichigan]

In my experience, such problems are usually caused by dirty and or bent contacts on the keypad.  One needs to carefully remove the keypad and plastic covers and clean the various copper spring contacts all around and possibly gently bend them so that they close properly.  It is a delicate and difficult job, but it can be done (If I can do it, anyone can).  Transplanting a good keypad from a junk phone is easier though.

Larry

[markosjal]

Princess keypads are illuminated and therefore less common and more expensive to replace. You may buy a used keypad only to find that it has issues too.

LarryInMichigan is probably right!

If you get only an individal (single or one pure) tone then you have an issue with contacts. Each button should produce two tones one for the row and anoher for the column (see image)

if you hear a DUAL Tone (not a pure, individual, or single tone) when you press a non-working button then you probably have to tune the coils. This is not impossible , but not easy.

I recommend you use asterisk to generate the standard INDUVIDUAL DTMF tone frequencies then compare those with the INDIVIDUAL tones (by pressing 2 keys simultaneously on same row or column to produce the frequency for that row or colunm).

With a good ear and a stable reference source like asterisk , you may be able to tune these. You will need PLASTIC tools to adjust the coils

You can also record these in asterisk and compare the recordings in Audacity (free open source)   

[Babybearjs]

if you are going to repair it, download the ITT TIMM manual from the TCI library, it shows how to service a touchtone keypad...