Author Topic: 701B not breaking dial tone  (Read 585 times)

Offline Scott

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701B not breaking dial tone
« on: December 30, 2018, 10:30:19 AM »
I am stumped. I have a 701B that will not break dial tone. I have switched out the dial with a known working dial, that one doesn't break dial tone either. Then I put the original dial into a different 701B and it works fine. So that leads be to think it is not the dial. I have triple checked the wiring not only with printed schematics but also with another functioning 701B. Everything matches. Could this indicate a network issue? Are there any other tests I can try to narrow down the possibilities? Any thoughts are appreciated. If photos will help please let me know. Thanks in advance.

Scott K.

Offline Key2871

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Re: 701B not breaking dial tone
« Reply #1 on: December 30, 2018, 11:22:48 AM »
Is the dial wired on the network correct?
Sounds like the blue and green leads are either touching or both on the same terminal. With the dial so you can see the back, rotate the dial, slowly let it return making sure that the pulse switch is opening and closing as it hits the cam.

Ken
« Last Edit: December 30, 2018, 01:31:46 PM by Key2871 »
KEN

Offline Ktownphoneco

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Re: 701B not breaking dial tone
« Reply #2 on: December 30, 2018, 11:36:51 AM »
Scott  ....   Occasionally the 701B was wired for manual service, but with the dial left in place.     If that is the case with your set, you will find that the dial is in fact wired to the telephone's network properly, but you will also find a jumper wire between terminals "RR" and "F" on the network.    If that is in fact the case, remove the jumper wire and test the set again and see if the dial is operable. 

Jeff Lamb

Offline Scott

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Re: 701B not breaking dial tone
« Reply #3 on: December 30, 2018, 11:48:45 AM »
Thank you for the reply. There are no jumpers from GN to R1 or from RR to F I can see. Could it be internal? This is a 495 A network. Both dials I have tried have been wired White to R1, Blue to F, White to GN and Green to R. Both dials work on the known working phone. Might this be a hook switch contact issue?

Scott K.

Offline Ktownphoneco

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Re: 701B not breaking dial tone
« Reply #4 on: December 30, 2018, 11:57:18 AM »
Scott   ....   Try this :  White wires are OK.    Green to "RR"  and  Blue to "F" and see if that works.

Jeff

Offline Scott

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Re: 701B not breaking dial tone
« Reply #5 on: December 30, 2018, 12:23:33 PM »
No go. Wired both dials I'm using that way and still not breaking dial tone. I've looked for information on how to test the network but haven't found anything so far.

Scott K.

Offline Key2871

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Re: 701B not breaking dial tone
« Reply #6 on: December 30, 2018, 12:42:55 PM »
Have you looked at dial switch, on the back side of the dial.
Rotate the dial, then turn it back slowly watch for contacts that open then close, do it very slowly there is a finger that rides on the can, that opens then allows them to close.
If those are not operating, the dial will not pulse and you will not break dial tone. You can pull the plastic cover off to allow you to view the switch contacts better.
Ken
« Last Edit: December 30, 2018, 01:19:52 PM by Key2871 »
KEN

Offline Ktownphoneco

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Re: 701B not breaking dial tone
« Reply #7 on: December 30, 2018, 01:11:00 PM »
Scott  ....  Ok, perhaps you may want to confirm that the entire set is wired correctly by comparing what's in front of you to a Bell schematic.      Go to the TCI Library.    On the home page, click on "Browse Library" - in Drop Down Menu click on "Wiring Diagrams", then click on "Western Electric", scroll about 2/3rd's of the way down the page to "Princess" and click that and move down page until you find "701-B".    look at right side of page and click on "View".     That will load a schematic diagram for your telephone set.   Print the page, then work through the diagram and check off each connection on the schematic diagram as you go to confirm each one is correct.   

You may want to check the pulse springs as "Key" has suggested to make sure the two springs are in fact opening and closing as each digit is dialed.

Jeff
 

Offline Scott

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Re: 701B not breaking dial tone
« Reply #8 on: December 30, 2018, 01:19:35 PM »
Thanks Key2871 for the reply. In the beginning I checked the dial over well and it appeared to operate correctly. This morning I put it into a phone I knew operated correctly and it worked properly. So it seems to me the dial is not the problem but I could be wrong. I decided to focus on the network so I got out my multi meter. I will gladly admit I have no idea what the numbers mean on it! But here is what I found when I compared the known working phone with the phone in question.
On the known phone when I used the meter on RR and GN I get a reading of .091
On the phone in question the reading is .039

Known phone R1 to F reading is OL.(I don't know what that means)
Phone in question .000

Known phone R1 to RR .016
Phone in question .013

Known phone R1 to GN .090
Phone in question .026

Like I said I don't have any idea what those numbers mean. But when they don't match it leads me to believe that there is a problem. So I'm asking, can the difference in readings between R1 to F mean the network is the problem?

Offline Jim Stettler

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Re: 701B not breaking dial tone
« Reply #9 on: December 30, 2018, 01:30:31 PM »

Like I said I don't have any idea what those numbers mean. But when they don't match it leads me to believe that there is a problem. So I'm asking, can the difference in readings between R1 to F mean the network is the problem?
Yes.
For quick and dirty troubleshooting , you don't need to know what the numbers mean, you are just comparing the numbers to see if they match or are different.

You can also flip the leads when measuring, this is in case there is a diode in the circuit. You should hold the meter leads in place for a moment, in case of capacitors.
--------------------------------------------------------------------------------
Going off hook activates the dial tone, Breaking the dial tone is a function of the dial. It sounds like your dial works, so the problem is most likely the network.
JMO,
Jim S.
You live, You learn,
You die, you forget it all.

Offline Key2871

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Re: 701B not breaking dial tone
« Reply #10 on: December 30, 2018, 01:33:46 PM »
Your welcome Scott, good luck with the phone.

Ken
KEN

Offline Ktownphoneco

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Re: 701B not breaking dial tone
« Reply #11 on: December 30, 2018, 02:02:00 PM »
Scott ....     I'm assuming your measuring resistance (ohms) with your meter.      But I've rarely searched for a problem in a circuit by measuring resistance, except for a specific component by itself.    There are a number of things which could cause a variation from one set to the other, and yet both sets are wired and operating correctly, so I would avoid trying to make comparison readings from one set to another.   In order to to do a resistance comparison, you would pretty much need to disconnect almost all components in both sets to do that by comparing each individual component from each set, and that would take a while, and may not isolate the problem, especially if it's a wiring issue.    A large percentage of problems associated with to sets with the same problem as yours, are solved by checking an accurate schematic with the actual connections on the set itself.    The other somewhat common issue is the integrity of each conductor (wire) and the connector located at one, or each end.    "That" issue is where an ohm meter can help by placing the probes across each end of the wire.    A good solid connection will produce a .000 resistance reading, meaning there are no breaks in the wire and / or connector.
Another common situation with sets which may apply to sets such as yours, involves the line connections.    Your line connection should be "Green - tip" to "L-1" in the network, and "Red - ring" to "L-2" on the network.    There should be no ground connection, as a modern telephone line no longer uses a ground.   It's also possible that someone "tinkered" with the set before you acquired it, and something is wired incorrectly.   
As I suggested earlier, pull up the schematic from the Telephone Collectors International Library web site and go through the wiring and compare the connections in the schematic diagram with those inside your telephone set.   Don't be be overwhelmed by the diagram, it's simply an electrical road map.      The terminals inside your set are marked, as are the connection points in the schematic, and the wires are colored, both in the diagram and in the actual telephone.     Just follow one wire at a time, and "take your time" doing it.   I'll be very surprised if you don't find a wiring issue somewhere.

Jeff

Offline Scott

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Re: 701B not breaking dial tone
« Reply #12 on: December 30, 2018, 07:48:03 PM »
Thanks Jeff, I was convinced it was a wiring issue as well since most of the time it is and I have never had a network problem before. But I have been using the TCI schematics and looking at a known working phone wiring and I think I have to resign myself to the fact that the wiring is correct and I have a bad network. Now I have to decide if I just close the phone up and put it on display or do I find a donor phone with the correct dates and rebuild this one. Thank you and everyone that has responded to my questions. Happy new year everyone.

Regards,
Scott K.

Offline rdelius

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Re: 701B not breaking dial tone
« Reply #13 on: December 30, 2018, 09:44:33 PM »
I beleive that there is a spark surpression between your dial connections between f and  rr. Try lifting the blue dial wire and the white slate wire from the f terminal .Connect them togather and see if you can dial out.

Offline Scott

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Re: 701B not breaking dial tone
« Reply #14 on: December 31, 2018, 02:24:28 PM »
Bingo! Nicely done, it works great plus the dial tone is much louder. But now what? What does the F terminal do? Do I bypass it altogether? Thank you very much.

Scott K.