Trimline - low volume dail tone and sound

[princessphone]

Just bought a nice Trimline touch tone '72. Cleaned it up a bit. It works however the dial tone and sound is very weak. I inter-changed the base and hand set with other Trimlines and determined that the problem is in the base unit. I checked all terminals, blew out the dust etc. but to no avail. What can the problem be? Anyone have any ideas?
Thanks, John DeJonge 

[jsowers]

What about the handset cord? If it's a '72, then it would have a large modular handset cord. Did you substitute a known good cord? Have you cleaned the large modular handset jack on that base? I'd use alcohol and if it's silver, you could try silver polish, making sure to clean off all the polish afterward. The early ones had silver contacts. Also sometimes those jacks will crack since they're plastic.

[princessphone]

Hi Jonathan,
Thanks for reply. Tried what you suggested but no luck. Tried more stuff and found out that problem is actually in handset and not in the base unit (should not have had that extra beer). I opened the handset and all looks clean. I do remember using a compressed air can on the receiver end of handset. I was able to remove the receiver unit but noticed no damage to the membrane. Tonight I will replace with an other one and see, I mean hear what happens. I'll keep you posted. Thanks again.
John   

[zapper]

Check the handset holes for crud.  Also check the receiver membrane for crud.  Either clean the receiver or replace.
Zapper

[princessphone]

To zapper, Thanks for suggestions. Tried these things but still no luck.
John DeJonge

[poplar1]

When this problem (low volume) occurs on other Western Electric models, it is usually the common contacts on the Touch-Tone pad that are dirty -- the ones that close regardless of which button is pressed.

The WE repair shop even installed a short black jumper to bypass those muting contacts. Later, on new 2223C Trimlines, WE no longer muted the tones in the receiver. This was not a problem since most people dial with the receiver away from the ear.

The bypass jumper may have been on the square button Trimlines only. If only we could find the BSRS (Bell System Repair Specs)...

[princessphone]

Thanks poplar1,
I'm not sure now if the voice volume was also low. What I did was I exchanged  the whole 861 network from another handset. That turned out to be very challenging, but a good exercise, but not as challenging as fixing the rotary dial of a Trimline.
The bottom line: All's well, the Trimline aint misbehaving. 
Thank you all for the interest and help. John DeJonge     

[poplar1]

There is a resistor that is normally bypassed (shorted) when the dial is not in use. The resistor is there to make the tones not as loud when you are dialing.  If those contacts are dirty, then the receiver will be in series with the resistor all the time, not just when the buttons on the dial are pressed. I'm not sure but it looks like you might be able to short terminal 2 and 3 with a jumper, although the easier thing to do would be to clean those common contacts.

See fugure 9:
http://www.telephonecollectors.info/index.php/document-repository/doc_details/10426-502-320-100-i5  (TCI library)