[mythtv-users] AC Hum/ weird lines, ETC (was Plextor Convertx CPU Usage)

Steve Peters - Priority Electronics steve at priorityelectronics.com
Tue Apr 8 04:01:26 UTC 2008

>> I do have a hunch that it is AC Hum. But how would I go 
>about fixing  
>> that?
>> I've already gotten a upc battery backup to help ground the 
>> Didn't
>> help much though. But any other ideas to fix this would be greatly
>> appreciated.
>AC hum in NTSC video shows up as a horizontal bar, sometimes 2 (120  
>Hz.) moving slowly up through the picture. Your description doesn't  
>sound like hum.
>Unplugging the fan helping is odd, is it just connected to 12 VDC or  
>are you modulating the fan somehow for thermal control? Do you maybe  
>have a marginal power supply?

OK, so it's not ac hum then...

My Power Supply is the included supply that comes with the IN WIN
IW-V605T2.J350SL Black-Siliver Steel ATX Mini Tower Computer Case

In the system, I have an nvidia 7300lt, 1gb ram, 2 of the pvr-500 cards, no
optical drive, but 2 ide hard drives (I don't think I'm overloading it).
Could it be something with the power supply or motherboard?

Any my mother board is the GIGABYTE GA-945GZM-S2 LGA 775 Intel 945GZ Micro
ATX Intel Motherboard

Also, the lines which look like about 50 light gray vertical lines going
through the picture across the entire screen don't happen with the tv
tuners. But, when the tv tuners have bad reception (us cable), but when I
unplugged the system fan (default one that comes with that system, plugs
into the motherboard) the reception gets better, also, the lines decrease,
but don't totally go away.

Also, both cards have different results, one has better reception on the
cable input and less lines on the svideo and composite inputs.

Lastly, every now and then, like every 10 to 15 minutes or so, the cable
input's sound pops and goes mute for a half second or so, then goes back to
normal. Very strange. This does not happen on the svideo with rca sound

Any ideas?

I feel like this one is like chasing a ghost.


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