Using TV to display audio signals.

you may have heard about

Wobblevision,
Wave Vessel
Analog Visualization Unit, AVU, Psychoscope, o-scope , b&w tv into a
large screen oscilloscope kits

 this is it all in one
Before we begin, I have to give everyone a warning.
DO NOT ATTEMPT THIS PROJECT!
MODIFYING TV IS A DANGEROUS PROCESS. DO NOT ATTEMPT THIS UNLESS YOU
KNOW THE DANGERS OF CAPACITORS AND
OTHER ELECTRONIC COMPONENTS. THERE IS A GREAT RISK OF POTENTIALLY
DEADLY ELECTRIC SHOCK, AND THERE IS
THE POSSIBILITY OF FIRE OR EXPLOSION.
IF YOU TRY TO FOLLOW THESE INSTRUCTIONS, NO-ONE CANNOT BE HELD LIABLE
FOR ANY DAMAGE OR DEATH CAUSED
WHILE BUILDING OR USING THE DEVICE		 warning
warning
warning
Before you begin read these safety instructions:
Safe Discharging of Capacitors in TVs and Video Monitors
cathode-ray tube Safety Issues
Deflection System Safety
There are two areas which have particularly nasty electrical dangers:
the non-isolated line
power supply and the CRT high voltage.

stay away from the red cable with the suction cup end.
after you have opened the TV unit wear rubber gloves! (longer sleeves better)

The principal of this audio signal displaying is that when TV is normally operated the Deflection Yoke generates a magnetic field and use it to direct the electron beam in the cathode-ray tube.  Deflection Yoke gets signals from
Deflection Circuit (Board) - Two of the wires control the horizontal motion, and the other two control the vertical motion. you just replace the Deflection Circuit Board signals whit amplified audio signals and there you go.
I have made some schematics to clear how to route audio signals to Deflection Yoke- these schematics are based on information from Censtrons Wave Vessel page and my own experiments. 
first you need to find out the two horizontal and two vertical wires - these instructions on Censtron page
will help you 
"The diagram above shows all six possible wire combinations. The
diagram is drawn from the angle of looking directly at the back of the
tube. The colors I used are just for reference,
and may be different depending on the model of the television."
"First clip and strip all four of the wires going to the tube, then
connect them all back up using alligator clips. Then, remove one of
the clips, and turn the television on. If you get a vertical line,
then the disconnected wire is one of the horizontal drive wires, if
you get a horizontal line, then you disconnected a vertical wire. Turn
the television back off, then follow the same process for the other
three wires to determine which direction each controls."
here you see the wires going to yoke

H=horizontal
Hg =horizontal ground
V=vertical
Vg=vertical ground

Here is the unmoded version

whit this you can see normal TV programs
here is the Censtron version
with this setup you get a bar that differens in length (a bit like
panel of Kit [car from Knight Rider] when it was speaking)		 kit effect
here is the Censtron version
with this setup you get vertical line that vibrates
here is the stereo version
with this setup you get pulsing circles circle
After reading this post on audiokarma.org forum i decided to ad second yoke...

quote DBerning on audiokarma.org "Magnetic deflection TVs of this era needed the deflection yoke for energy
storage for the flyback pulse that was used to provide high voltage for the CRT. Because I was using the yoke for
audio deflection, I mounted a second deflection yoke somewhere in the TV cabinet so that the inductance from the
winding could be used in the flyback-based high-voltage circuit."

here is a link you might want to read:
http://audiokarma.org/forums/archive/index.php/t-3208.html

Here is my Philips TX:
[img]http://i17.photobucket.com/albums/b69/dnny/TVWV.jpg[/img]

one month later:

Okay i did find the extra yoke - but it was not the same type - so this is what happened:
the picture was extremely bright! i mean really really bright. I was very happy for a while it looked so cool.
after some 15 -30mins both of the TV sets fuses were burn and the unit was extremely warm. So what i assume
happened is that i drived the CRT with too much voltage/current and it started to produce X-rays! .

What did we learn? -
if you want to ad the extra yoke to extra brightness you need to measure the yokes inductance first and then
find another yoke that has the same properties.
(or if you want a cheapo X-ray machine just replace the fuses whit thick wire);)

Day later:

I'm feeling lot better now

i called to The Radiation and Nuclear
Safety Authority of Finland and asked if i have been exposed to
any radiation danger by moding my TV. and they said that there is very
small possibility to get enough radiation from CRTs - in their test
the maximum X-ray radiation from television has been 100mGy/h (hundred
milliGrays per hour) and after that the tube has collapsed.

To get symptoms from X-rays you need to get at least 100Gy.
The symptoms are then the same type of skin burns you get from sun.

The X-ray radiation on tv-set is stronger in the back of the tube than
in the front. The X-ray born's when electrode hits the phosphor wall.
X-ray bounces back to the inner walls of
tube. it keeps bouncing and gets weaker and dies - the glass is
thicker in the back so some x-rays get through but we are talking of
really small amounts of radiation.

After replacing the fuses i tryed it again, so i connected the coil
lets say it was 50mH to
the points of horizontal and horizontal ground of the Deflection
Circuit(Board) - and wow it
was cosmic - the beam was so bright - it was just like looking to sun.
well i realized that the unit heated a lot - so i attached two ventilators . . .
and i took it to "koneisto" (The Festival For Electronic Music in Helsinki)
it was in  stage with Aavikko. It lasted one hour, almost the whole gig and
died of over heating :(  but i have to say that no TV has ever be so
bright! all the time it looked that it will explode any minute :)
this is the setup what i did - daniels koneisto setup

so i have been looking for the next TV (victim) to my experiments - and i got now a correct size coil from the
broken Philips TX
and meanwhile Censtron has made their first color vessel:

"We just finished making the first Color Wave Vessel, with it you can
now make the
visualizations any color from invisible to white."		 color

Two months later:

My Friend gave me a old soviet travel-TV that was not working but, it could display the
usual noise. So i did the things described in this article - but with a 2mm pinjack -patch
panel and speakon connector - so i can connect straight to my amp.

here are some pictures:
not much space inside so i removed the speaker
the patch panel made of perspex:
the whole unit:

this video shows the beauty of electron beam bouncing whit music
Questions and comments other people made:

"Just a word of caution, not all amps are suitable to drive inductive loads.
I once blew up a home amp driving an inductive load (coil) - but it
had a higher inductance
than a TV deflection coil has (I used it with an iron core coil to
bring metal strings into vibration).

So maybe use an old amp instead of the "good one"."



"have you ever tried all the other possible connections?
have you found other interesting visual effects?

my reply: are trying to s Some links to DIY Oscilloscope's

http://www.intio.or.jp/jf10zl/tvosc.htm


instructions to make GBDSO  (GameBoy Digital Sampling Oscilloscope)

http://www.reinerziegler.de/gbdso_uk.pdf

LED-matrix oscilloscope
http://www.geocities.com/SiliconValley/Lakes/7156/articl3.htm

there is a neat how to on geek technique. org
how to make Mac se/30 audio visualizers
http://geektechnique.org/projectlab/707/how-to-make-mac-se30-audio-visualizers

[img]http://i17.photobucket.com/albums/b69/dnny/bentmacse-21.jpg[/img]ay I'm keeping something as secret ? :)
i have try the other two possible connections, but unfortunately they
don't look so stunning as the ones i have documented.

remember:
[b]never connect your amp to the deflection circuit output's[/b]
[b]never short horizontal whit vertical from deflection circuit[/b]

Some links to DIY Oscilloscope's

 There is also DIY article titled TV-skooppi published in finnish magazine Tekniikan Maailma 8/81
(article not in the link, you will have to find the magazine)

TVosc

instructions to make GBDSO  (GameBoy Digital Sampling Oscilloscope)

LED-matrix oscilloscope

there is a neat how to on geek technique. org
how to make Mac se/30 audio visualizers