Thank you Sargeguy!

[Babybearjs]

I got the 306 and here are the results. after all the cleaning, I got the phone to work really nice... I exception though... the ringer works through the ballast tube, but for some reason, only when the case is open. I bought a #6 dial that went to a payphone and changed out the face from black to metro. (used of course) and the phone dials out just fine. to anyone who knows this model phone, what are the operating restrictions on the #372A ballast tube? I'll go to the W.E. website and pull up the original specs, but given that the phone is connected to modern equipment, I may have to convert the phone over to a 302C.  do these tubes ever burn out?

[unbeldi]

You have to make sure that the wires or spades on the dial do not impair the movement of the clapper when the set is assembled.  This was particularly a problem with No. 6 dials and I believe there is a BSP that warns of the problem. With a No 6 dial the clearance is much reduced.

What you call a ballast tube is nothing such, it is a essentially a diode that breaks down with a small current on the starter electrode and then conducts.  It is filled with a reduced pressure of inert gas that contains a fraction of a radioactive element that aids in the electric breakdown.  The cathode is not heated.

The tube logistically replaces the ringing condenser in 'normal' sets. It was used to eliminate the impedance to ground in grounded ringing systems when the set is not ringing. When the tube is not active it has an almost infinite resistance.  This prevented imbalance on party lines and eliminated inductive noise when this was a problem in the environment.

The tube operates on polarized ringing systems.  The ringing was polarized either on a negative or positive potential, meaning it pulses from 0 to plus or from 0 to minus. Diodes conduct in only one direction and thus the sets were wired differently for the negative and the positive signaling stations on the line.

The tube can usually be made to work on modern lines which have a fixed polarity, but you have to observe the polarity requirements and the ringing has to be superimposed on the DC, which is normally the case.

It is 'cool' in a way to see the tube light up during ringing, sometimes the black tube insulation has flaked off a little and one can peek inside.  The black insulation prevents light from interfering which can lead to false ringing, as it can ionize the gas just as the radioactive additions.

Diagrams with another sparse description may be found here:  http://www.classicrotaryphones.com/forum/index.php?topic=12416.0

The standard WECo wiring diagrams aren't of much help to understand the operation of the ringing circuit, but hopefully my diagram from that thread is much clearer:



In this you see clearly how the tube is wired in place of the condenser, with the starter electrode (red wire) connected to one side of the line to tickle the gas into a breakdown state.

Since the tube has a very high impedance, the ringer does not need to have high-impedance, and material can be saved, it is therefore a special kind, a B3A, with ca. 2000 Ω.

[unbeldi]

do these tubes ever burn out?

Here is another thread that discusses the topic in some depth (you started it!):

http://www.classicrotaryphones.com/forum/index.php?topic=12626.0

It also discussed aging of the tubes.

The tubes have nothing in them to "burn out" though. As long as the glass envelope stays intact without leaks they should last, but material deterioration of the cathode may reduce their ability to eject electrons.

[HarrySmith]

Yes, I had a couple of 302's that would ring when open but not when I put the case on. It was the dial spades & wires getting in the way. Repositioning the spades and wires should solve the issue.

[andre_janew]

I have a 302 with a 6J dial and I never had that problem.  I must have routed things properly from the beginning.

[poplar1]

Proper way of dressing the leads on a 6-type dial, or with newer style ringer mount:
http://www.classicrotaryphones.com/forum/index.php?topic=11824.msg125855#msg125855


http://www.telephonecollectors.info/index.php/document-repository/doc_details/3338-c34-103-i2-station-dials-2-4-5-6-7-maintenance-tl

[Babybearjs]

the funny thing is.... I went ahead and changed the 195C Capacitor to a 195B and wired the bell through the cap.... the phone rang fine. so, because of this I have discovered that the 372A tube is not powerful enough to ring the bell and the 195B capacitor is. so, to keep the phone original, but properly operational on todays phone lines I kept the 372A tube intact and wired EXCEPT for the black wire.  I terminated the black ringer wire and the slate cap wire on the E terminal and wired the black tube wire on the GND terminal and moved the yellow line wire to the screw on the switch hook (stored). this way, the bell can be connected to the tube if desired, or to the capacitor as needed to ring on todays equipment. But, my experiment did work.... the tubes still can run the ringers but just not as good as the capacitors. so in the end, Thank you Greg for the 306 phone, it now has been returned to service.

[Sargeguy]

Your welcome, I'm just glad it found a home with someone who appreciates it more than I did!

[Babybearjs]

and it works great and has another 100 years of service.....