110 lines
5.7 KiB
Plaintext
110 lines
5.7 KiB
Plaintext
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***********************************************************
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*
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MEMBER NAME: TVCABLE *
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*
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***********************************************************
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S C R I B B L E V I S I O N
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11-MAY-90
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If you open the back of a TV, there's the neck of the picture tube sticking
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out the back. It has a 'yoke' around it that is made of two large
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saddle-shaped coils, usually of lacquered copper wire. Sometimes the coils are
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wrapped in tape or plastic or an insulation of some kind, but they're usually
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just copper.
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_____
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| \ Yoke (wraps around tube neck)
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| \ =====
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| \-----------\-|
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| Picture Tube |-| (plug on END of tube neck remains connected)
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| /-----------/-|
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| / =====\
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|_____/ Yoke \ Wires from YOKE to CHASSIS
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\ (cut these and connect YOKE to STEREO)
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\
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\ (leave the CHASSIS end of the wires UNCONNECTED)
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-------------------------
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| TV Chassis |
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-------------------------
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OK. Sometimes there is a bundle of wires or a multi-wire cable that goes from
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the yoke coil to the chassis. (the yoke coil defects the light spot back and
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forth so that it scans out the TV picture. Check an encyclopedia or TV repair
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book at a library for illustrations or block diagrams etc. if this isn't
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clear) anyway, the yoke coil will be connected to the main chassis/circuitry
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of the TV set by several wires, sometimes there's a cable connector or
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multi-pin plug/socket arrangement on the end. What you have to do is
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disconnect ALL wires that lead from the chassis to the yoke coils (do this
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with the TV _OFF_ : HIGH VOLTAGE!!!). If the yoke wires have a connector,
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just unplug it from the chassis. If the yoke wires are soldered on to the
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chassis you will have to cut them. There will also be wires running from a
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plug/socket on the very end of the neck of the picture tube. Leave these
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connected - they are needed to warm up the picture tube so you get an image
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on the screen.
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Now, turn the tv on and carefully touch a pair of speaker wires connected to
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a playing stereo, (or just run a 9 volt battery over to the yoke wires) try
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out various pairs of wires until you see the spot of light that will be in
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the center of the TV picture (you have disabled scanning and should only see
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one dot on the face of the picture tube) uh, try connecting voltage or
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speaker audio into pairs of yoke wires until you have determined which two
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pair of wires move the dot vertically and which pair move it horizontally.
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You can use a mirror to watch the TV while fiddling about in back with the
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yoke wires. Once you have determined the vertical and horizontal pairs, just
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run a set of speaker wires from your stereo over to the yoke pairs and turn
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up the volume, and adjust the left-right balance until the music or radio you
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are listening to makes the screen scribble around and pulsate to the music.
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If you have an oscilloscope, it's even easier - just put the oscilloscope in
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X/Y mode and feed one channel of a walkman into the horizontal probe and the
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other channel (left/right channels here) into the vertical sweep probe. The
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oscilloscope will display a scribble of the music coming from the walkman.
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Old black and white TVs work better than color TVs for making scribble
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visions. The only requirement is that light appears on the screen when you
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turn on the TV set (that is, you can see the scanning pattern). You may have
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to adjust contrast and brightness to get the best scribble trace on the
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screen.
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If you are using a 'good' TV you might want to install DPDT switches to switch
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back and forth between scribble and normal TV modes. Make sure the DPDT
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switches isolate the chassis scanning signals from your stereo completely or
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you can blow things out.
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This is a diagram of the contacts on the bottom of a DPDT switch.
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Make two of these, one for the Left/Horizontal Yoke-to-Stereo
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connections and one for the Right/Vertical Yoke-to-Stereo connections.
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You only need to do this if you want to switch back and forth
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between TV and Scribblevision modes. Make SURE the Chassis wires
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will get connected to their original corresponding Yoke wires when
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the switch is flipped.
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|wire to Yoke Coil
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------o o o-----
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wires from chassis wires from stereo
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------o o o-----
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|wire to Yoke Coil
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You can also reverse the leads from the chassis to the yoke to make the TV
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display a mirror image or upside-down picture. Mirror reversal is convenient
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if you don't want to be forced to read adversizement graphics when they
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appear on the screen.
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Oh, if you watch a mono audio source in scribble-vision mode, you will just
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see a diagonal line instead of a full scribble pattern. You might have to
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adjust the tone controls on the stereo in a wierd way because bass sounds
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make larger patterns than treble sounds, but treble sounds produce more
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complex textures. Experiment around.
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Outlaw
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Telecommandos
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?????????????????
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?????????????????
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