Glen wrote in message . ..
On 6 Oct 2003 07:24:22 -0700, (Lydokane) wrote:

Is the transformer grounded or is it 2-prong? Where does the ground
for the MP3 run to? If you don't have an earth ground reference, then
you're just asking for trouble with a stepper motor(hard drive).

Glen



Glen,
The MP3 player is a 2-prong (red & black). The transformer that I am
currently using is actually an old laptop transformer (Toshiba I
think). It outputs 15V @ 3A. It doesn't have a 3-prong grounded
plug. It is polarized. I also have another transformer that outputs
12V @ 3A (or 4A... I can't remember). This other transformer does
have a 3-prong plug. And I know it will work with the MP3 player
because I have used it in the past.

Any sugestions?

Thanks,

PR



** Original message **
This is a repost of a message that I posted through google... almost
two weeks ago. It finally got posted yesterday.

I have a hard drive based MP3 player. It is designed for automobiles
but with a transformer I can use it in the house or at work. The
problem is it puts out a large amount of RF interference. When I am
at home it isn't a big deal. When I am in the car or at work it
becomes a problem. The player literally wipes out the entire FM band.
Every station turns to static (actually you hear the wirring noise of
the hard drive). I am sure it is ?airborne' interference. If I am in
the car and I pull up next to somebody, and their radio is loud
enough, I can hear my interference from their radio. Naturally, it
also affects my radio. At work it is even worse. I work in a
factory, which is mainly a steel, and cinder block building. With the
push of a button I can render every radio in the shop useless. I have
been told not to bring it back, unless I want to be flogged, tarred
and feathered.

What could be causing the interference? I know the unit has a regular
3.5" hard drive. I don't believe this could be the problem because we
have several (about 12 or 15) computers on the shop floor that all use
a 3.5" HDD. I know the unit has a eprom that is programmed to decode
the MP3 files and I think it has a small processor. It doesn't run
any kind of internal amp. Since it is designed for use in an
automobile it is drawing 13-14 V and 3amps.

What could I do to reduce/eliminate the interference?

Thanks,