>A good friend of mine has a 486DX2/66 that has a rather *** habit of
>interfering with the TV reception and hence has his parents whining quite
>a bit when he is using it.
If it was bought from a dealer as a system, then check with your
government's equivilant to the US Federal Communications Commission as
the system should not interfere with the TV in usual situations.
Here are some tips:
1. If the TV uses unshielded twin-lead, try converting to coax (and
watch out for unshielded coax to twin-lead converters. If you are
using cable, make sure it is completely shielded and not a cheap
slip-on-slip-off type or one with a few flemsey ground strands (if it
bends easy and looks nice, then it probably isn't any good). If the
TV doesn't have a coax input, then you can try to construct a shield
using solderable metal or copper tape.
2. If the computer is near the TV (i.e. on the other side of a wall or
connected through the same AC) or is near the antenna/cable, try to
relocate it as far away as possible.
3. Minimize the cables running from the computer and/or try to
rearrange them to minimize the interference. Wiggle them a bit while
looking at the TV to see if it makes any difference. If they aren't
completely screwed-down, then tighten them. You can also buy clip-on
ferrites for the cables. You can also buy shielded cables... I would
suggest trying to borrow some just to see if they actually help.
4. If the computer's case isn't shut, then of course shut it. If it is
shut, then try using copper tape to seal up all the long gaps like you
would use weather spripping for your home... BUT DON'T SEAL UP THE AIR
HOLES. Basically, you are looking for long gaps and slots rather than
small round holes (don't worry about slots around the power supply
right now). Also, if you put any tape near the circuit board or
exposed connector, make certain that it doesn't short anything out.
5. If still a problem, try using metal screen taped with copper tape
over the air holes on the case (including over the power-supply). Make
sure the screen is of medium size to minimize the affect on the air
circulation (not too small to impede the air nor to large to be
ineffective). To be effective, it must be taped down all around. to
observe the effects and minimize your waste of copper tape, you can
try just holding it firmly against the metal chasis and observe the
TV.
6. You might try to also use an AM or shortwave radio (even better
might be a handheld TV) and see if you can use it near the computer to
pin-point the leakage.
One problem that you will find is that once you seal up one hole, it
will start leaking out another. This is especially true if you are
using a board which was not approved for home use and thus has very
strong RF output. Unless you are a certified computer technician, it
is unwise to attempt to add any suppression circuits to the boards.
Tom
--
url: http://www.racesimcentral.net/.***ia.edu/~tdb8q/ [updated 28 Nov 94]
