GPO Bellset 26 on Canadian/US network

[unbeldi]

You have to look at the data sheets firsts.
10 k  is far too small to stop all bell tapping.  That only amounts to putting two ringers in series.

I would expect that it has to be 10x larger or more in cold state. In addition its curve needs to be quite steep at ambient temperature, over a small temperature range, as there isn't much energy to burn. I think the response curve should be logarithmic, not linear as is usually hoped for when measuring temperature.

PS: The thermistor you got there, is for temperature measurement/sensing.  I think you should look for the types designed as inrush current limiters.  Steady state ringing current for a typical 1 REN ringer is probably around 10 mA.

[dsk]

I can not find any, tried a 100K, and got no ring, util I held my fingers on it, then the ringing started, and increased slowly even when I removed my fingers.

Went back to the 10K's but did put 2 in series, works good enough for me.

dsk

[unbeldi]

That shows it is way to slow, it needs to be more responsive, i.e. a much steeper response curve.
With the 10k unit, you are probably simply reducing the current so that the ringer still rings, but the current spike during bell tap is too low to make it strike the gongs.
You can probably achieve the same effect with a simple 10kΩ resistor.

[Jack Ryan]

The Thermistor 1A has a cold resistance of 200k and conducts after about 0.4 seconds of ring current being applied. This results in a ring delay of about 3 seconds (because of the ring cadence).

This is a very fast response that I have not yet found in a modern thermistor.

In the mean time, I have found that a resistor of about 4k7 (and probably 3k3) generally will suppress bell tinkle - albeit with a small reduction of ringing intensity.

Jack

[Fennec]

Following your discussion with great interest, since this is a new subject for me. Question - wouldn't introduction of a 3k3 resistor in series with the ringer lower the volume of the receiver? I had to remove this one from the line as I have found that sound level I am getting with it is somewhat lower (I am using an upgraded 2P version, BTW)...

So, I am putting up with a tinkle for the time being. And - yes, it happens when I am moving handset off and on the hook, and also several seconds later I get one more tinkle, possibly due to residual charge release from the capacitor.

I guess if there would be a 1A thermistor in line, sound level would not suffer, as resistance of a thermistor would drop with current flowing through it... Does this sound right?

[Jack Ryan]

Following your discussion with great interest, since this is a new subject for me. Question - wouldn't introduction of a 3k3 resistor in series with the ringer lower the volume of the receiver? I had to remove this one from the line as I have found that sound level I am getting with it is somewhat lower (I am using an upgraded 2P version, BTW)...

The resistor should be in series with the bell - it won't affect receive level. Can you check its connection?

So, I am putting up with a tinkle for the time being. And - yes, it happens when I am moving handset off and on the hook, and also several seconds later I get one more tinkle, possibly due to residual charge release from the capacitor.

I guess if there would be a 1A thermistor in line, sound level would not suffer, as resistance of a thermistor would drop with current flowing through it... Does this sound right?

The thermistor won't affect receive level either but again, because it is in series with the bell.

Have you tried a rubber band around one bell coil and the armature? Low tension - use a knot to adjust it.

Regards
Jack

[unbeldi]

Following your discussion with great interest, since this is a new subject for me. Question - wouldn't introduction of a 3k3 resistor in series with the ringer lower the volume of the receiver? I had to remove this one from the line as I have found that sound level I am getting with it is somewhat lower (I am using an upgraded 2P version, BTW)...

So, I am putting up with a tinkle for the time being. And - yes, it happens when I am moving handset off and on the hook, and also several seconds later I get one more tinkle, possibly due to residual charge release from the capacitor.

I guess if there would be a 1A thermistor in line, sound level would not suffer, as resistance of a thermistor would drop with current flowing through it... Does this sound right?

If you put the thermistor IN LINE as you state, you would indeed have problems, especially with a 200kΩ thermistor.  The speech energy would never heat it up enough to drop its resistance.

The thermistor or a resistor should be in series with the ringer only, not with the entire telephone set, as shown:


    L1                   Line                          L2
    |                                                  |
    |                                                  |
    |                     condenser                    |
    |        resistor      ||                          |
    +--------/\/\/\/-------||---------[ringer]---------+
    |                      ||                          |
    |                                                  |
    |                                                  |
    rest of telset


The elements are indicated, "resistor" is the new component, substitute thermistor if you like.

[dsk]

Following your discussion with great interest, since this is a new subject for me. Question - wouldn't introduction of a 3k3 resistor in series with the ringer lower the volume of the receiver? I had to remove this one from the line as I have found that sound level I am getting with it is somewhat lower (I am using an upgraded 2P version, BTW)...

So, I am putting up with a tinkle for the time being. And - yes, it happens when I am moving handset off and on the hook, and also several seconds later I get one more tinkle, possibly due to residual charge release from the capacitor.

I guess if there would be a 1A thermistor in line, sound level would not suffer, as resistance of a thermistor would drop with current flowing through it... Does this sound right?

I have to admit to test this out, just to learn.  Earlier I have used a spring from a pen to make a tension spring to the ringer, and that works great! Now I am experimenting around this UK solution to learn, and hopefully find a component good enough to do the job.

As some mentioned above, this has to be put in series with the ringer, but not in series with the voice circuit.

dsk