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nal is useable based on the graphic.
• Audio-Signal: Just like with the vid-
eo signal, the DSO201 can also display
the audio signal. This makes it easy to
determine if an audio signal is present
or if there’s a problem inside the re-
ceiver. A small tip: make sure the vol-
ume isn’t turned all the way down, the
mute function isn’t active or if only the
digital audio output is active…
You’ll always come across some-
thing that doesn’t work and yet with
the DSO201 oscilloscope the problem
can typically be isolated in just min-
utes. Sometimes the LNB voltage fails,
sometimes the 22kHz generator be-
comes defective. More often than not
though it’s a problem in the cabling:
the wrong cable is connected to the
multiswitch and no signal reaches the
TV room. The DSO201 can help in an
instant.
If you’re not expecting a powerful,
professional-class digital oscilloscope,
you won’t be disappointed with the
DSO201. The scope is quite small and
relatively inexpensive. It has become
a standard piece of test equipment
here in our test center; it takes up less
room than a multimeter and is a per-
fect troubleshooting tool.
1. The DSO201 is programmed with the help of the DfuSe demo application. The device is
turned on by holding down the VOL button and connected to a PC via the USB interface.
DfuSe should show “STM Device in DFU Mode” in the upper left.
2. First you should create a backup the preinstalled firmware. Click on “Choose” to name
the file and then on “Upload”. When the status line below shows “Target 00: Upload
successful!” you can safely upload alternative firmware. In an emergency you can reload
the backup.
Our test center is al-
ways busy. There are
receivers, signal analyz-
ers, TV cards, etc. that
constantly need to be
tested. Unfortunately,
you can’t get around the
fact that there will some-
times be failures. And so
I had my own little dumb
mishap: everyone knows
that you shouldn’t plug
in or unplug an LNB ca-
ble while the tuner is
turned on so as to avoid
any short circuits. But if
you’re in the middle of a
test and need to quick-
ly move a cable around,
you might be inclined to
ignore this golden rule.
Last night while I was
undergoing an extreme
satellite card test that
involved switching back
and forth between differ-
ent antennas, I wanted
to connect the motorized
antenna one more time.
I unplugged the cable
One Day
in the
Test Center...
and then wanted to plug
it in to the antenna when
a small spark jumped
from the center conduc-
tor to the outside shield.
This wouldn’t be the first
time that this happened
to me but at some point
in subsequent tests I no
longer had a proper sig-
nal. Of course, I thought,
the tuner had failed. But
it wasn’t that simple; I
was still able to display
transponders with Cra-
zyScan although the an-
tenna wouldn’t turn and
actually the spectrum
should have appeared
differently.
To make a long story
short, I used to DSO201
to determine that the
tuner was no longer sup-
plying the necessary
14/18V. That I was still
able to receive tran-
sponders was only be-
cause the antenna had
a twin LNB. The neces-
sary voltage was being
supplied by other satel-
lite signal analyzers that
were also connected.
That’s why it was pos-
sible to receive a sig-
nal but not possible to
switch between polari-
zations. And it’s exactly
these kinds of “failures”
where the DSO201 would
be a perfect tool to find
out what’s going on.
A useful tip: if you want
to move cables around on
a satellite PC card with-
out having to turn the PC
on and off, simply end
the TV application. This
would also turn off the
power to the tuner and a
short circuit would then
not cause any damage.