Hello everyone. This might be a new one. I came across a customer that is experiencing rolling horizonal bars(hum bars) on his T.V. Now I have dealt with this problem before with great success, but here is one component I have never seen or used before. "TVGuardian" this product filters the bad language. When I bypass this product the bars go away. When the customer turns on the heater, dish washer or vaccum bars get worse.

Here is the list of customer's components:

Philps 32 inch tube television
Panasonic VCR/DVD (this is acting as TV tuner, RF in, Composite out to TVGuardin)
TVGuardian (composite and analog audio in, composite and analog audio out to T.V.)

If anyone has any input or experience with this product let me know.

Thanks,
Dean

I see I'm the first person whom you did not ask to respond as I have no experience with this product. But I have experience with other products, reasons for hum, and ways to solve your problem. So here goes.

How long, and since when, has this been happening? This is key to the solution. I think the TV guardian is not being made any more, so it has been around for a while. If it has always done it, why the sudden need to fix it?

You should do some homework with the following so you can suggest to the client how much it might cost to fix this. My seat of the pants estimate for it is about $600, being both troubleshooting time and possible hardware. It could easily be more. He might decide it is not worth it for his kid to watch the big TV, and he might move it to a smaller TV where it doesn't cause problems for the rest of the family. I don't know. Just suggesting.

If the problem is new, you must find out everything that has changed in the house and its systems. This could include adding an antenna, making a better ground on the cable drop, installing a dish, et cetera. You are looking for a change in how or where there are connections to electrical ground, cold water pipe grounds, or even, heck, ground type grounds.

Does the TV Guardian have a three-prong power plug? If so, that could cause a ground loop that introduces 60 Hz into the ground of the video lead.

We like to simplify things with the concept that the signal on the center lead of a video cable is what we see, but in reality we see the signal that is the voltage difference between the ground and the hot lead. That means that if there is voltage on the ground lead, it will be picked up as part of the video signal.

It is not legal to permanently disable a third-prong ground, but if you get a three-prong to two-prong adaptor and TEMPORARILY connect the thing without its ground connected and the problem goes away, you know that's where the problem arises.

The legal solution is to use ground isolation transformers on audio and video leads. It might work to put them on the leads coming out of the Guardian. It might work to put them on the leads going into the Guardian. You might need them on both inputs and outputs. Look these up (locate Jensen Transformers) so you have an idea how much they might cost if you need a set for the input and another for the output.

There is also an excellent hum troubleshooting guide on the Jensen Transformer site. It will walk you through the equipment and your setup to pin down the source of the hum.

Thanks
I will call up Jensen Transformers

Perhaps you're the guy to answer this question. Might seem dumb, but if ya don't know, ask somebody, right?

It's possible that voltage has gotten onto some water pipes at an installation we did, causing a proplem with one of our pieces of equipment. Would I just put a lead on the pipe and the other on the ground on the water heater? If I wanted to check for voltage on the ground, what would I put my other lead on? Just anything else that is grounded? Thanks.

If ya coulda just waited another month, this would be a ten year thread resurrection. Oh well. It'll happen sooner or later!


The earlier discussion involved analog video where ground currents produce horizontal bars that slowly roll up the image. I haven't seen that kind of result from hum in digital TVs, and it's hard to believe hum just doesn't exist any more -- it's more believable that the manner in which digital displays make their images make them less susceptible to hum.

What are you seeing that makes you think there's hum?

What do you know that makes you point to water pipes?

In other words, examine all you know before going off to find out what you don't know.

Do what I suggested in the earlier post.

Also, add a ground. Connect a wire to some place in your system, say AVR chassis ground (NOT a signal ground) and touch it to different ground places, including at least local power socket ground lead and a water pipe or two. After you've done that, come back here and tell us what you've found.