monitor flicker from cable line

[camellights]

Hi, I don't know if this is the best forum considering all of the potential factors in my problem, but I figured I try here first

This isn't an immediate problem, as I've worked around it, but I'm still curious, and haven't been able to find any reference on the web of anyone else with the same problem.

I currently have a celeron 300a clocked to 450 (100mhz fsb, with 1/3PCI and 2/3 AGP) on an abit bx6 rev.2 mobo, various cheap NIC's, ATI rage magnum 32 (later called fury), and a panasonic s17 monitor. My cable comes from charter@home through a SurfBoard.

When first getting cable, a little over half a year ago, the people came and installed, using a PCI NIC I had in my box, and after the installation, I had 1Mbps (after a 56k winmodem, whoopee!), but my monitor had a flicker to it .. not a strobing, but more like the roll you see when a big monitor has refresh set too low (fwiw, it was @75hz, which worked fine for the previous 2 years). Changing the refresh didn't affect the flicker. Unplugging (powering down) the modem didn't affect the flicker, nor did changing or removing splitters. Clearly, to me, there was a problem with the physical line (charter's responsibility).

After several bungles of having @home tell me charter was responsible and charter tell me that it must be @home's problem, I finally got a real tech to my apt.

I know he was real because when I told him that I had previously been able to draw a small electrical discharge off my coax line (true), he told me that I was clearly mistaken because cable line doesn't carry a current.

Previously, in addition to the spark, I had also discovered that if one unplugged the cat5 and then slowly moved the plug toward the jack in the NIC, the flicker would return at close (<1mm) proximity, without even touching the two.

The real pisser is that when I tried to demonstrate both of these for him, it didn't work. May have been something fixed by one of the previous people who came out that didn't directly address the flicker issue (I do know my tv picture improved though).

All the same he plugged his real fancy professional doohickey into my cable line and determined that everything should be working just fine. The only oddity was signal strength, iirc (this was 8 months ago, so I am making up the numbers to the best of my memory).. He said that spec was 3-5, but that I had 7 .. which he immediately said was not a problem and made it sound like a good thing I had such a strong signal (hello? they don't call it SPEC for nothing?). Then the real nice professional technical man from charter and his real nice professional technical dohickey went away. After telling me to call @home, of course.

As time, experimentation, and vexing chats with tech support played out, I discovered that the flicker was present when using a PCI NIC or a USB NIC, but not when using an ISA NIC (what I've been using since). Recently, I purchased a DVD player, and tried to use an old ATI PCI card for TV-out. Lo and behold, when the card was connected to the RCA "IN" port on my VCR (which is connected to cable via coax, of course), my flicker returned.

I know that it is something specific to this cable line, because I have had a PCI video card connected to a cable system elsewhere that had no such problems, but according to any measurements that charter is capable of making, their line is just fine, just super.

I'm not saying my box might not be a partial culprit - the PCI-bus-only thing strikes me as a little suspicious, not to mention being unable to find web documentation about anyone else with this problem.

Short of me purchasing another mobo of the same model to see if it is a mobo flaw conspiring with some cable anomaly (i.e. short of me purchasing anything),does anyone out there know of any plausible explanation, or way to test for a satisfactory answer, or wild UFO interference hypotheses?

Thanks much

[rodrod5]

are the outlets in your house grounded??
do you have the pc and the modem and the dvd all plugged into the same outlet??
does your modem split from a line in your house and the line also goes to your tv?
can you get a fresh run from the tap for your modem if you do not already have one??
do you have cable tv also?? probably so on charter.
if so does your tv have good reception??
have you tried to see if the problem is the same if you have all tvs, dvd's, and vcr's off the cable line IE only the modem being on the cable in your house everything else disconnected , does the problem continue with just the modem on the cable in your house?
is your modem plugged into a grounded outlet?? not one with 3 prongs , but is the ground actually grounded and working properly?
hope this helps

[camellights]

Thanks for the reply .. Sorry, I should have made clearer, since this is a cable *modem* forum, I suppose

The problem arises when there is a connection between the cable line entering my house and my box, whether there are any other powered or unpowered devices between the connection or not(excepting the PC peripheral making the connection to the USB or the PCI bus, but I've tried with 3 different NIC's and two different RCA video adapters with the same result, so if it is a problem with my PC, it would be with the mobo, I think). (ie. it's not the modem, it's the line) - which btw, I didn't mention, but the modem was replaced, which had no effect on the problem.

[rodrod5]

your outlets grounded???

[camellights]

Given the recent construction of the building and the size of the parent corporation, I would strongly suspect so. I'll try running the ground to the kitchen sink (and hope there's no PVC in between) tomorrow and see if it changes anything.

[Storm90]

Sounds Like maybe you need to update the drivers for your video card or replace. Or maybe make sure it not next to the nick, Plus if you have it over clock it could be slowly killing the video card. If it is a factory card this may be the problem. Plus make sure the video cards not shareing the same IRQ the nic is. It could be pulling down on the video card. If you also think it the cable. I would consider the modem first. It has the eletric in it not the cable. I would look in to both. If it been doing this for year. also move that modem as far you can get it away from the computer. Plus any other eletrical device you have next to it. This will some times cause this proublem Good Luck! Your cable should have had a ground on it when it was in stalled. I use to install it and we always ran a ground for the internet connections. These are just a few things I have seen cause this problem. Some monters are fussy as to what kind of eletical stuff is next to them.

[camellights]

Okay, I have:

new mobo (asus cusl2c)

new power supply

dedicated ground wire for the power outlet to my computer (which powers all peripherals)

separate IRQ for NIC

I still have the flicker, so I am 100% sure it is coming out of my cable line. If anyone can hazard any other ideas as to the technical explanation, that would be cool, but at this point I'm wondering if anyone has any advice as to how to approach Charter to fix this thing .. I'm 100% positive it's them, but according to the best they can tell (that being a cable guy with an attitude) they say it's not their problem. What would be the best thing to do to get them to deal with this problem?

Thanks much

[dmsmed]

Iwould check the shield portion of the cable line for voltage, I bet you'll find one. Then I would ground it on your end.

[camellights]

Thanks, that seems to be the problem. Don't have a voltmeter, but ran some wire from the external connector on the coax to my water pipes and it cut down on the flicker significantly (though not completely). I would guess that to properly do it, I would need to penetrate the exterior of the cable and solder or braid into the shielding and run it to the nearest grounded power outlet.. (?) Would you reccommend I try to get the cable company to do it (could they ground it outside at the box maybe?), and if not, where in the line would you recommend I place the ground?

Thanks much