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old Danish phone

Started by long jumper, August 15, 2022, 04:40:46 PM

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long jumper

The other issue is that when dialing off hook not only can't you break dial tone Clapper Clapper won't pull in

long jumper

Is the counter suppose to work off pulsing contact?
Because the way its wired it's  wired to shunt contact. On photo  of dial blue and brown are pulsing  contacts.


I have to look at the dial on mine to see if it ias equal,  I have never touched it because it is just working, but your dial is related to the GPO no 10 that you may find info about here:

long jumper

Switched both sets of wires from pulsing contact to shunt contact no dial tone.wired back as originally wired. dialed out transmits received and rings. Put resistor capacitor back in circuit let charge 5 min dialed 1st digit counter Clapper pulled in and released as it should but did not break  dial tone. I have checked every wire matches diagram. Does anyone think another component should be added somewhere else ?


Without the diode, capacitor, resistor it works, but with, it does not break dial tone when those components are in the circuit? You are sure that the resistor is 15.000 ohms? (or more) Disconnect the resistor only, and test again. (The counter will not work, but you should break the dial tone) If it breaks the dial tone try higher resistance. The charging time will probably increase but if you get it working :)

long jumper

I did every thing suggested in the post counter worked fine still couldn't break dial tone. Do you think a 200k ohm resistor would make a difference?

long jumper

Does anyone have any other suggestions?

long jumper

Can't figure out why
 When I remove the  J terminal wire off of counter we can break dial tone

long jumper

I put a 27k ohm resistor in series with 150k resistor was able to activate counter and break dial tone but not always able to dial a full 10 digit number. Need  help to figure what other size resistor to dial full 10 digit phone numbers.

long jumper

Here is a diagram of what i did to get it to break dial tone,but sometimes could not dial out full phone numbers. So its hit & miss. I think with  someone's  assistance we could tweak this to work

long jumper

Also you have a better chance of dialing out a complete phone number right after capacitor was fully charged. But not always,if you dial out before  5 min you can dial a few numbers and then can no longer break dial tone.


Quote from: long jumper on October 07, 2022, 03:50:52 PMI put a 27k ohm resistor in series with 150k resistor was able to activate counter and break dial tone but not always able to dial a full 10 digit number. Need  help to figure what other size resistor to dial full 10 digit phone numbers.
Your line is more sensitive than mine, maybe you should even try to increase the resistance value even more, maybe double it.  Then the charging time of the capacitor will also increase, but you have to test out how long time it will take to charge enough to make the counter count.


Quote from: long jumper on October 07, 2022, 07:49:38 PM. . . if you dial out before  5 min you can dial a few numbers and then can no longer break dial tone.

I read through the whole topic again and id not see anything about the dial itself. Did you ever check you dial speed? Dialing a few numbers I've seen where a dial is too slow and the central office times out causing the line to go back to dial tone. The specs are 8 to 11 PPS IIRC in the US Bell System.

Once you begin to dial a number, you should not be hearing dial tone again. Upon completion, the CO will send a ring signal or busy signal or whatever until the phone is answered, on the other end, or you hang up.

A slow dial, on the edge of the CO capabilities to record and step pulses, can cause this effect you have noticed (quoted above). After dialing starts, you should not hear dial tone unless you hang up and start over so the "you can dial a few numbers and then can no longer break dial tone" statement does not make sense.

If you haven't, you can use a wall clock with a second hand to see if your dial returns from 0 in about 1 second which would be a dial speed of 10 PPS. If it takes 1.25 seconds, your dial would be running at about 8 PPS and dial speed along with the sensitivity of your central office to pulse dialing may combine to cause the dial to "time out."

Also, when dialing, the main spring is tightest, has the most energy when releasing the flinger wheel. A dial that needs cleaning and lubrication may produce acceptable pulses when first released but as the dial returns to a stop, that last few numbers with be sent to the CO at a PPS speed slower than the first few. I documented this somewhere on the forum some time ago with a graph showing the dial PPS speed as it returned from dialing 0. Even with a governor, a dial in need of cleaning will slow down over 10 digits and if you dial is slow, and your line is sensitive to dialing speed, it may be that the CO recognizes the first few pulses but not the last few due to the slow down dropping the dial out of spec.

If your dial is near 10 PPS (pulses per second), then it's something else but slow dial speed would be eliminated as a cause of your problems.

Another thing to try is to clean all of the dial leaf switch contacts, to burnish them, using a piece of paper card stock to remove any buildup of crud on the contacts (pull a piece of cardstock back and forth through the contacts a couple of times when they are closed).

The contacts themselves are coated with rare earth minerals to keep them from corroding over time so don't use anything like sandpaper or emery cloth, just clean paper card stock. Anything other than card stock will remove the rare earth minerals and allow the contacts to corrode from that point forward.


The detail on dial performance follows for those who are trying to understand what I said above about dial slow down. It may or may not apply to this topic but for those who missed my post in 2018, here is a recap.

Analysis of a subject dial's speed showed it to be an average of 8.35 PS (purple line) when dialing 0, pulsing 10 times.

Plotting the time of each pulse showed that while the dial started off in spec at 8.74 PPS, the last digit pulse rate was an out of spec 7.73 PPS.

In other words, the dial started to send pulses to the CO within spec (8-11 PPS) but dropped out of spec after the 6th pulse (8.00 PPS on the graph is at the black line). The last 4 pulses were below spec and the CO would not recognize the pulses went back to dial tone or sent a time out error sound signal.

While the thin brown line shows a standard straight trend line, the thin blue shows an polynomial trend line and it shows the dial spring/governor keeping the speed loss fairly straight until about 8 PPS when the combination of spring energy and dial friction began to slow the dial speed and an increasing rate (you can see how the thin blue line begins to move away from the thin brown line).

So, a dial that has a marginal dialing spec (just above 8 PPS) to begin with can drop below the minimum dialing spec and cause the CO to no longer count the pulses, to step the system so the call can be placed.

long jumper

Teleplay I agree with you 100% I do not question your expertise. Have not checked dial speed. But when dialing  out on landline with out any components all calls break dial tone and are completed. That's what puzzling to me. I will try everything on your post. If I can't adjust I will send dial to Steve H. Thanks let you know


Forgot the dial works without the counter wired in. Dial is probably good. Strange problem, indeed.