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WE 302 loud click when depressing the hook switch plungers

Started by shortrackskater, August 09, 2017, 11:12:38 PM

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shortrackskater

(I'm adding AGB's first response after I posted this question which resulted in the thread being split)

I have a loud CLICK when I depress the hookswitch on my WE302.

Alex G. Bell
If there is a click that indicates either:
(1) there is some DC through the receiver, or
(2) incorrect contact sequence in the cradle switch, or
(3) some resistance in the RD handset cord lead, or
(4) some other mis-wiring.

One possible reason for DC is in the receiver is leakage in the 2uF capacitor section connected by its RD and BK leads between 101A IND "C" and the BK dial terminal.  You should check for DC across the receiver with a DMM set to the 200mV DC scale.

A long handset cord or one with higher than normal resistance in the RD lead for some other reason will cause the voltage drop produced in the RD conductor as a result of transmitter current, to appear in series with the receiver, causing a click.  The more voltage drop the louder the click.  In the extreme case of RD being open the click will be very loud because all transmitter current will be passing through the receiver.

The GN & BR-BL cradle switch contact must close after YL & BR-YL when releasing the cradle buttons and long enough after for fluctuations in current in the line to have died down, and it must open before YL & BR-YL when depressing the buttons.  If they operate in the wrong sequence there will be a loud click.  If they operate almost simultaneously there may be a weak click.  If depressing and releasing the cradle switch buttons slowly produces no click but letting them pop up does the contacts are operating too close together in time.

shortrackskater
Replaced the handset cord, which had resistance on the red lead.  Still have a loud click when depressing the hookswitch.
Mark J.

Alex G. Bell

Quote from: shortrackskater on August 09, 2017, 11:12:38 PM
Replaced the handset cord. Still have a loud click when depressing the hookswitch. Otherwise phone works fine.
But not when operating the dial? 

If that is the case there is no DC in the receiver circuit (as there should not be) and the HS contact sequence is wrong.  The GN & BR-BL contacts must open before the YL & YL-BR when depressing the buttons.  The sequence can be adjusted by bending the shortest thick stop spring located between the two contact springs.

If there are clicks from dial operation that means there is DC in the receiver and most likely there is a wiring error somewhere.  It's also possible the 2uF capacitor section appearing on the RD and BK capacitor leads is leaky or shorted.  Put a DMM set to measure 0-200mA DC in series with either capacitor lead and check for current, which should be zero.  Then put it in series with the WH handset cord lead, which also should be zero.

poplar1

Quote from: shortrackskater on August 09, 2017, 11:12:38 PM
Replaced the handset cord. Still have a loud click when depressing the hookswitch. Othewise phone works fine.


When you depress the plungers, which hookswitch contacts open first: the contacts closest to the dial (green and brown-blue),
or those closest to the back of the housing (yellow and brown-yellow)?

One way to check for clicks is to remove the green hookswitch wire from GN on the 101A induction coil. You should not hear a loud click in the receiver while removing or reconnecting this green wire. (If you do hear a click, then adjusting the hookswitch contact sequence will *not* help!)
"C'est pas une restauration, c'est une rénovation."--François Martin.

shortrackskater

No dial clicks.
I'll get back to this tomorrow and post my findings.  :)
Mark J.

shortrackskater

Sorry my "tomorrow" ended up being later!
The handset contacts were all opening at the same time. That was my fault. When I got the phone, for whatever reason, the hookswitch was all twisted and I bent it back the best I could, not realizing about the timing.
I now have significantly less CLICK... it doesn't hurt my ear. The click "volume" is the same as all my other phones now.
As for the capacitor, is it common for those to eventually fail? I'll do the next test ASAP for the capacitor just to see what shows up.
Mark J.

Alex G. Bell

Quote from: shortrackskater on August 14, 2017, 12:03:58 PM
Sorry my "tomorrow" ended up being later!
The handset contacts were all opening at the same time. That was my fault. When I got the phone, for whatever reason, the hookswitch was all twisted and I bent it back the best I could, not realizing about the timing.
I now have significantly less CLICK... it doesn't hurt my ear. The click "volume" is the same as all my other phones now.
As for the capacitor, is it common for those to eventually fail? I'll do the next test ASAP for the capacitor just to see what shows up.
Good!  Not common.  Under what conditions do you hear a faint click?  When there is silence after dialing a digit or with dial tone present?

shortrackskater

It occurs at all times when depressing the hook switch, silence or with dial tone present. I have the same click with all my other phones: two more 302's and my 202.
Mark J.

Alex G. Bell

Quote from: shortrackskater on August 14, 2017, 12:35:33 PM
It occurs at all times when depressing the hook switch, silence or with dial tone present. I have the same click with all my other phones: two more 302's and my 202.
Perhaps there is slight DC leakage.  It should be very faint or inaudible.  Measure the DC current through or voltage across the receivers of the phones which do this.

shortrackskater

If I measured correctly I have 22mv across the receiver.
Mark J.

Alex G. Bell

Quote from: shortrackskater on August 14, 2017, 10:03:14 PM
If I measured correctly I have 22mv across the receiver.
That small voltage is probably due to the voltage drop in the common RD handset cord conductor from transmitter current flowing through it.  It's the reason 500 sets use 4-conductor handset cords: with a varistor across the receiver the small DC voltage would affect the varistor. 

The click from 22mV should be almost inaudible, not objectionable.

shortrackskater

Compared to what it was before, it's fine with me. And, again... it's equal to my other phones now. Just sounds like a typical "hang up" sound.
This phone will be a Christmas gift for my sister and brother in law. I repaired the minor cracks, replaced the handset wire and now fixed the click.
I'll say this topic is solved!
Thanks, again, for the help AGB and everyone else.
Mark J.

Alex G. Bell

Quote from: shortrackskater on August 15, 2017, 01:33:47 AM
Compared to what it was before, it's fine with me. And, again... it's equal to my other phones now. Just sounds like a typical "hang up" sound.
This phone will be a Christmas gift for my sister and brother in law. I repaired the minor cracks, replaced the handset wire and now fixed the click.
I'll say this topic is solved!
Thanks, again, for the help AGB and everyone else.
Good!  You're welcome.