The last time I tried to use our Toshiba SD-1700 DVD player it was
acting up. The sound and picture were all there, but there were also
lots of tiny dots which just looked like multicolored snow. These dots
looked random at first, but eventually we could see that the frequency
of something was drifting and the dots were organizing into diagonal
lines (upper left to lower right.) At first the diagonal lines looked
like they were about 1" apart (25" screen), but as time passed these
rows of dots would wander around a bit and eventually line up into
more populus rows, next with about 2" between rows and finally with
about 4" between rows. It seemed clear that some frequency was beating
against the horizontal sweep frequency and that this frequency was
changing as something warmed up.

I didn't notice any change in the angle of the lines as things warmed
up, but it may have.

The spots tend to be light, so are most noticable against dark
backgrounds.

I tried another disk and that one displayed the same symptoms.

I have checked all the connections and they seem fine.

I have played a tape and that also seemed fine.

Our TV is a '73 Zenith 25CC25, so the DVD player has to play thru a
cheap RF modulator from MCM onto channel 4. Right now I have no way of
knowing whether the problem is due to the player or the modulator.

If I adjust the fine tuning off a bit, so that the picture is on the
verge of going B & W, the dots seem to disappear, but I think this is
only because I'm actually already losing color.

I'll check and adjust the colorburst frequency in the TV, but I
haven't done that yet. It's been a long time; I'll have to pull out
the Sam's.

Before I waste a lot of time trying to chase down this problem, do
these symptoms sound at all familiar to anyone? I'm just hoping for a
suggestion as to where to start looking.

thanks,

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Our TV is a '73 Zenith 25CC25, so the DVD player has to play thru a
cheap RF modulator from MCM onto channel 4. Right now I have no way of
knowing whether the problem is due to the player or the modulator

Try using the player on a different television.

If this symptom does not exist when played on a different TV, then the problem
could be with your 1973 Zenith set or with the MCM RF modulator.

To test the modulator, simply try it on a different TV. If it checks out okay,
you may want to consider getting your Zenith checked out, primarily the tuning.
You may just have to squirt some tuner cleaner in the tuner parts since I
doubt your TV has automatic electronic tuning. - Reinhart

Jim Adney wrote in message . ..
The last time I tried to use our Toshiba SD-1700 DVD player it was
acting up. The sound and picture were all there, but there were also
lots of tiny dots which just looked like multicolored snow. These dots
looked random at first, but eventually we could see that the frequency
of something was drifting and the dots were organizing into diagonal
lines (upper left to lower right.) At first the diagonal lines looked
like they were about 1" apart (25" screen), but as time passed these
rows of dots would wander around a bit and eventually line up into
more populus rows, next with about 2" between rows and finally with
about 4" between rows. It seemed clear that some frequency was beating
against the horizontal sweep frequency and that this frequency was
changing as something warmed up.

I didn't notice any change in the angle of the lines as things warmed
up, but it may have.

The spots tend to be light, so are most noticable against dark
backgrounds.

I tried another disk and that one displayed the same symptoms.

I have checked all the connections and they seem fine.

I have played a tape and that also seemed fine.

Our TV is a '73 Zenith 25CC25, so the DVD player has to play thru a
cheap RF modulator from MCM onto channel 4. Right now I have no way of
knowing whether the problem is due to the player or the modulator.

If I adjust the fine tuning off a bit, so that the picture is on the
verge of going B & W, the dots seem to disappear, but I think this is
only because I'm actually already losing color.

I'll check and adjust the colorburst frequency in the TV, but I
haven't done that yet. It's been a long time; I'll have to pull out
the Sam's.

Before I waste a lot of time trying to chase down this problem, do
these symptoms sound at all familiar to anyone? I'm just hoping for a
suggestion as to where to start looking.

thanks,

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

Jim,

It sounds like you're getting interference from the switching power supply
in the DVD player. I've seen the "swirling dots" interference caused by
compact fluorescent lamps, electronic neon sign power supplies, or even
cheap TV or VCR's own switching power supplies, when receiving the low-VHF
channels on indoor antennas.

In addition to checking connections, as you have done, try physically
moving the DVD player away from the TV. If the interference
weakens or goes away, you're getting radidated noise from the DVD's
power supply. There is a length of (unshielded) twin lead running from
the antenna terminals on the back of the set to the tuner at the front,
which can pick up noise from devices sitting on top of the TV.
You may also have a poor connection on the shield of any coax cable
between the DVD, modulator, and TV. Try swapping coax cables from another
set or your VCR and see if it cures the problem.

I doubt the problem is the modulator. You could always try running the
DVD player thru a VCR's line inputs and see if you still have the dots.

If you've eliminated the connections/cables, then you probably have one
or more capacitors failing in the DVD player's power supply, if you used
to have a clear picture and now have the dots.

Mike
WB2MEP