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Joined: Jan 2005
Posts: 15,402 Likes: 18
Moderator-Vertical, Vodavi, 1A2, Outside Wire
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Moderator-Vertical, Vodavi, 1A2, Outside Wire
Joined: Jan 2005
Posts: 15,402 Likes: 18 |
My guess then is that the second pair is providing enough capacitance to 'absorb' any induced hum. This would often happen on paging adapters that were connected directly to CO lines. What we did in these instances was to connect a 'half ringer' module from a standard NID across the line to eliminate the hum. Keep in mind that inductive hum can come from the tiniest of stray voltages, especially when a line runs over long lengths of quad (non-twisted pair) wire. This drop wire is just that, shielded quad. With the sheath not grounded, it picks up just about anything out there like an antenna. https://i.ebayimg.com/images/i/400465573437-0-1/s-l1000.jpg
Ed Vaughn, MBSWWYPBX
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Joined: Oct 2006
Posts: 1,417 Likes: 7
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Joined: Oct 2006
Posts: 1,417 Likes: 7 |
Read the conductors with an ohm meter for shorts, opens and grounds.
What does it sound like with the barn inside wires disconnected?
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Joined: Feb 2005
Posts: 12,356 Likes: 4
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Joined: Feb 2005
Posts: 12,356 Likes: 4 |
There's leakage between the red and yellow and or leakage between the black and green. Put em' together and there is no place to leak to except themselves.
-Hal
CALIFORNIA PROPOSITION 65 WARNING: Some comments made by me are known to the State of California to cause irreversible brain damage and serious mental disorders leading to confinement.
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Joined: Jan 2009
Posts: 854 Likes: 1
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Joined: Jan 2009
Posts: 854 Likes: 1 |
I agree with Hal. I bet if you took a simple VOM meter you'd see faults in that buried cable. Are the NID's one each end of this OPE properly grounded and is shield on the cable itself properly bonded?
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Joined: May 2002
Posts: 17,746 Likes: 37
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Joined: May 2002
Posts: 17,746 Likes: 37 |
I'd test it, but I'm with Ed.
Retired phone dude
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