Re: Hauppauge card giving me a shock

["John Andrews" <groups@xxxxxxxxxxxxxxxx>]

Keith

Cheers for this, makes sense.

So can I connect the aerial to my house's earth? Or is there a better way
to
get rid of this voltage?

And also, I *HAVE* blown a motherboard before by plugging a leaky(?) aerial
into a PCI Hauppauge card, so be warned.


----- Original Message -----
From: "Keith Doxey" <ukha@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Tuesday, November 02, 2004 8:33 PM
Subject: RE: [ukha_d] Hauppauge card giving me a shock


>
> Hi Anthony
>
> A couple of posts amalgamated together below for ease of reply :-)
>
> Shocks from Aerial leads is quite common. The cause is that the
majority
of
> domestic video kit eg TV's and VCR's/Satellite receivers are double
> insulated do not require an earth connection. However, they also
contain
> switch mode power supplies and these almost always leak a small amount
of
> mains current to the accessable circuitry, this is not a fault, just
an
> undesireable "feature". This leakage current is within safe
limits but can
> at times give you a tingle.
>
> Where it causes problems is when you have multiple pieces of equipment
> connected together as it makes the total leakage current greater
thereby
> giving a more noticeable shock. Chris commented that boosters
"cause"
> shocks. Well sort of..... because the main reason for having a booster
is
to
> drive multiple sets, it follows that there will be multiple leakage
currents
> making the total leakage higher. Actually a booster can lessen or
eliminate
> the effect as many of them have an earth connected which kills the
leakage
> totally.
>
> The reason for the sparks is that the PC case is earthed and the high
> voltage (but extremely low current) on the aerial lead is arcing
across.
>
> It isnt really anything to worry about, just be aware of it and try
not to
> touch both sides of the the circuit (eg plug in one hand, other hand
on PC
> case) when inserting the plug.
>
> Of course, if the sparks are similar to the arc from a MIG welder then
you
> do have a bit of a problem :-)
>
> Hope that helps
>
> Keith
>
>
> > -----Original Message-----
> > From: anthony.kirrane@xxxxxxx [mailto:anthony.kirrane@xxxxxxx]
> >
> > I began to notice that the TV picture on my kitchen PC would,
over time,
> > become worse and worse.  I went to check the aerial cable going
into the
> > Hauppauge PVR 350 card and I got a very noticeable electric
shock.  I
> > thought, oh well some static that had caught me by surprise. 
Then I got
> > another one.  I noticed that if I run the coaxial plug across the
metal
> > casing of my PC (I know - I know!) I can visibly see little blue
> > sparks.  I don't get this behaviour from any of the other aerial
leads
> > which are all coming from a single booster.
> >
>
> > From: christopher purves [mailto:CHRIS_PURVES@xxxxxxx]
> > I have found boosters cause the shocks - too much amplification
perhaps.
> > Certainly I used to get shocks all the time in my old house.
Different
> > ground levels perhaps.
>
>
>
>
>
>
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