75 Volts off TV F-connector?

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Our TV reception, from a roof antenna, was intermittently flaky. Trying to find the problem, I got a shock when I touched both the TV F-connector and coax cable antenna lead. So I put a tester on and to my surprise got a 75 volt reading.
It's also 75 volts between the TV F-connector and the outlet ground plug hole or outlet screw. And, there's 75 volts between any connector on the TV and any of these grounds. I'm also getting ~40 volts off the VCR F-connector, and ~50 volts off the DVD player *housing*.
Best I can determine this is the case with all house circuits. I plugged the TV into several, using extension cords, and carried the DVD player around to plug it into all circuits. I also get ~30 volts off the housing of an old stand mixer in the kitchen.
This isn't normal, is it?
I checked as many outlets as I could get to with a GB plug-in circuit tester, and all test correct. All outlets are at 125 volts. I opened the main panel and the one subpanel to see what I could see, and all looked right, though I really don't know what I'm looking for here.
What would cause "hot" appliances, and how do I track this down?
Thanks!
--
Luke

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75 Volts?
Hmmm dunno,, but sounds out of whack to me, especially for an antenna.
DOes it have a signal booster in the cicuit?
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Luke,
I saw the same thing in a house 10 years ago. It had a floating ground. We were putting in a new heat pump and got lit up when we cut the Freon lines. This is really dangerous. It can kill you or damage all your electronics or BOTH. Unless you know a lot about electricity, have the test equipmentm and know how to use it - DO NOT MESS WITH IT. This not the job to learn on!! Call a licensed electrician, this is not a good place to save money by doing it yourself!!
Stretch
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Luke. I also had this happen years ago. I had hi volts from antenna connecter to earth ground. Turned out to be the TV. The items you checked were most likely 2 wire plugs with no ground connection. Warren
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This is Turtle.
I seen this about 10 years ago on one job and it was the VCR messing up. The VCR was putting 115 volts on the Cox's Cable line coming into the house.
Take all the DVD , TV Boosters , or VCR out of the circuit and hook nothing up but the TV and you will see a difference if it is one of them. I had a 2 man crew hunting the power source over 3 hours in a attic and found it at the tv. I'm not in the TV and VCR business but the Customer of a big account had this problem.
TURTLE
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Does the TV have 2 prong plug or a 3 prong plug?
Are you using a digital Voltmeter?
Try this with a test lamp with a 25 Watt bulb.
It is normal for 2 prong appliances to sometimes have a small amount of leakage. A digital voltmeter will respond and show this leakage.
If this is a 3 prong applicance then something is very wrong and maybe dangerous
And if it is either 2 or 3 prong and you can see any light at all of a 25 Watt light test bub then something is VERY wrong and it is VERY dangerous.
Mark .
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No. Just straight coax from roof antenna.
--
Luke


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On Sun, 3 Apr 2005 18:36:26 -0500, "TURTLE"

Thanks. I already did that. I disconnected all audio/video connections. With *only* the TV plugged in, I get 75 volts off the F-connector and other outputs. ~40 volts off the VCR F-connector with *only* the VCR plugged in. And ~50 volts off the DVD player housing with only the DVD player plugged in. Also ~30 volts off the kitchen stand mixer housing, and the DVD player housing is hot on other circuits, too, so obviously disconnected from the TV and VCR.
--
Luke


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On Mon, 04 Apr 2005 00:44:49 GMT, pjm@see_my_sig_for_address.com wrote:

I'll ignore the personal attacks ;-). I know I'm beyond my abilities on this, which is why I asked, and as you suggest I was going to call an electrician first thing tomorrow morning. Just curious, what's a "lifted" ground or neutral, and why do all other appliances (computer, clocks, radio, etc.) seem to work okay?
--
Luke


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I didn't believe it at first, either :-). Yes, only two-prong appliances show hot. Grounded appliances, like the washer, dryer, stove, as best I can test, aren't hot. I had the antenna grounded to the main house electrical ground, when I disconnected that, I still get hot two-prong appliances, testing between the appliance F-connector or housing and either the antenna lead or ground on an outlet.
--
Luke


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It's OK Paul.
We all know you are the worlds foremost expert in the use of your hand as a .... tool.
And I still forgive you.
Your friend, Matt
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Luke wrote:

The voltage on the mixer points to a household wiring problem, and the floating neutral makes the most sense. Get it fixed.
Voltage on things like TVs and VCRs is often normal (but probably not in this case) because of low-value filter capacitors connected between chassis ground and the AC lines. These capacitors are small enough, no bigger than .005uF each, to limit 60 Hz AC current leakage to safe levels, just a few milliamps. There's also a low-value capacitor in series with the F-connector's center pin, also for safety isolation, but TV power supplies usually provide no isolation and have the TV's chassis connected directly to the neutral wire (why TVs came with polarized plugs long before most other appliances did). Sometimes the chassis is even held above ground, at 60-90VDC (be sure to measure with your meter set to both AC volts and DC volts).
I don't understand why your TV antenna mast and cable aren't grounded for lightning protection and to prevent shock (any dead birds or rats around the antenna?). However in this case that could have caused damage to your video equipment.
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This is Turtle.
Unplug everything and just read off the two ends of the house and entrance cable to if it is coming in or backing up on just the cable. It has to be coming from somewhere 1
TURTLE
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wrote:

This is Turtle.
Paul Milligan above here telling of hacks is nothing but a air condtioner software salesman and has not a clue as to what your problem is. The only 120 volt item that he may work on is his razar to shave with in the morning when it will not run. Now he does know a bunch about software to tell about air conditioners and heating system as to what size you would need to install. I one of the so call hacks he speaks of have held Electrican licences for over 30 years and in the hvac business for over 40 years. Also i run my own hvac business and all paul runs is his head. Watch who you listen to on the newsgroups.
TURTLE
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This is Turtle.
Spoken like a true software saleman. I think Mell used the same words.
TURTLE
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You Whizzzzed over his Master Electrical licences in electronics. He never seen # 2 wire.
TURTLE
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This is Turtle.
Hey Paul Where are you working at now or just tring sell software from home?
TURTLE
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pjm@see_my_sig_for_address.com wrote:

Well, licensed electricians don't work on TV's. TV repair men and electronic techs do. And in most locations there NOT licensed like electricians or HVAC men are.
I do agree. If its truly leakage, it can be deadly. Most modern TV's are hot chassis. That means they don't have a direct from the power line power isolation transformer like in the old days. They turn the AC line into a high DC voltage and then switch it with a secondary transformer into the low DC rails required for the TV. This is the "cold" side of the TV.
This cold side of the TV is where the signal processing and the antenna input are. If there is a leakage fault in the TV, it could cause a voltage on the antenna terminal. But you have to differentiate between a phantom voltage and a fault. A good TV shop will have a tool like a Sencore that can easily measure if any surface of the TV has a abnormal amount of AC leakage.
Leakage can go both ways. EC&M magazine has had some doozy examples of how this can happen. Like a guy who had the foil insulation of his house at AC line level when a nail went through the siding and nicked the hot side of a piece of romax.
Another issue is reverse wired AC outlets. A $10 home depot AC outlet and polarity checker will tell you if the hot and ground and neutral are intact in any household outlet.

Since most modern TV's are two wire, if the TV works its would be pretty hard to have a lifted neutral at that outlet. Reversed hot/neutral maybe. For those that don't know, ground and neutral are suppose to be bonded together in the service panel. Even though there at the same potential, the ground is for safety only and NOT suppose to be a current carrying conductor in a non fault situation. Many cable TV drops develop a voltage problem when the ground strap to the households ground rod or water pipe is missing or is corroded or loose.
Bob

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pjm@see_my_sig_for_address.com wrote:

Well, if its only the mixer you need an appliance tech then. A smart electrician should be able to understand the problem.
One big issue on leakage is phantom voltage. And understanding what that really means. Most modern DVM's have such a high input impedance that they can read a voltage that really not there. A older analog meter like a simpson 260 would not have this problem since it has a much lower input impedance. Some people have run into this issue measuring a voltage on a un energized circuit in house wiring. They put the DVM on the dead circuit and read 30 to 60 volts or so and think they have a problem. When in reality its the capacitive coupling of wires close together generating this "phantom" voltage. Put any kind of load on the wires and it goes away. Capacitive coupling can cause this effect in other devices too. A small load and it goes away. In any case, a leakage test with proper test equipment is the best way to put an end to the issue.
I have had and fixed TV's with excessive voltage on the F terminal. And the TV's DID have an internal fault.
Bob

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I am strongly tempted to say that you are having fun with us. Grounded appliance (three prong) have the chassis attached to the ground. If your ground at the breaker box was broken, and the ground wires were shorted to a hot, you could get a voltage off the chassis. This would require urgent attention. But you would not get a reading off the chassis of ungrounded appliance (two prong) because they are not attached to anything.
Either explain the problem in more detail, or go away.
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