Haig, your attention please

[KRSESQ]

After putting up with some odd behavior of my cable modem for some time now, I had a cable guy in to check things out. He tested the signal and lines both inside and outside the house and all was good. He scratched his head and started isolating lines and testing them with a volt meter, and after some effort discovered that both my Marvel G200 and Marvel G400 capture cards are feeding a spurious 58-60 volt signal into the cable grounding lines, even when both computers are switched off. This voltage doesn't adversely affect the picture quality on any of the tvs or the tv capture quality of the cards, but as I said, it does funky things to my cable internet, periodically spontaneously resetting my modem (at least, we presume this is what's causing it. The cable modem tested okay also).

When the cable is disconnected from the BOB, or when the BOB is disconnected from the card itself, the voltage goes away.

Is this normal behavior for these cards?

It now occurs to me that we didn't test it with the computers up and running. I'll check that angle myself shortly and post the results.

Thanks,

Kevin

system 1:
AMD TBird 1200
Abit KT7A
Marvel G200
TBSC
PD 5.41
VT 1.52
Win 98SE
DX 9
MP 9

system 2:
AMD Athlon 2100
MSI 745 Ultra
Marvel G400
TBSC
PD 5.41
VT 1.52
Win98SE
DX 9
MP 9

[Haig]

... cards are feeding a spurious 58-60 volt signal into

The ground of the cable (external shield) is mechanically attached
to the PC casing. So if the ground of the cable goes up, so does
the shell of your PC. Perhaps the problem has to do with your home
120V wire installation. Is the 120V ground (120V is line + neutral
+ ground) of your PC properly connected to the wall outlet ? If so,
is the wall outlet grounded properly ? Without this ground connection, then yes there could be ground lift caused by the PC power supply. I am pretty sure that our card is not at fault here.

To check if the ground is properly connected, you could buy a little
120V wiring checker device with 3 lights at $5 from the local hardware
store. Especially in old houses, wiring had no ground before 1965
or so (at least here in Quebec). Over time, people upgraded their wall
outlet from a 2 prong to 3 prong model, thus leaving the ground
floating, hence the problem.

[KRSESQ]

Well, that is something because this is an older house and the wiring on those outlets is not grounded. I'll try to puzzle out a way to ground them properly and check it again.

Thanks

Kevin